Bi 


THE  LIBRARY 

OF 
THE  UNIVERSITY 

OF  CALIFORNIA 


PRESENTED  BY 

PROF.  CHARLES  A.  KOFOID  AND 
MRS.  PRUDENCE  W.  KOFOID 


ELEMENTS 


OF 


PHYSIOLOGY. 


BY  A.  RICHERAND, 

PBOFESSOR  OF  THE  FACULTY  OF  MEDICINE  OF  PA1US,  SURGEON  IN  CHIEF  OF  THK 

HOSPITAL  OF  ST.   I.OUIS,  MEMBER  OF  THE  ACADEMIES  OF  YIKXNA, 

PETERSBURG,  MADRID,  TURIN,  &C. 


TRANSLATED  FROM  THE  FRENCH, 
BY  G.  J.  M.  DE  LYS,  M.  D. 

MEMBER  OF  THE  ROYAL  COLLE&E  OF  SURGEONS  IN  LONDON. 

WITH  ANNOTATIONS, 

BY  N.  CHAPMAN,  M.  D. 

Profesior  of  the  Institutes  and  Practice  of  Medicine  in  the  University  of  Pennsylvania; 
COPIOUS  NOTES  AND  AN  APPENDIX, 

BY  JAMES  COPLAND,  M.  D.  OF  LONDON; 

AND  ADDITIONAL  NOTES, 

BY  JOHN  D.  GODMAN,  M.  D. 

LECTURER   ON   ANATOMY   AND    PHYSIOLOGY. 
FIFTH  AMERICAN  FROM  THE  LAST  LONDON  EDITION. 


PHILADELPHIA : 
PUBLISHED  BY  H.  C.  CAREY  &  I.  T.K',. 

IS25. 


Eastern  District  of  Pennsylvania,  TO  WIT: 

BE  IT  REMEMBERED,  That  on  the  twenty-seventh  day  of  Septem- 
ber, in  the  fiftieth  year  of  the  Independence  of  the  United  States 
of  America,  A.  D.  1825, 

H.  C.  CAREY  &  I.  LEA, 

of  the  said  district,  have  deposited  in  this  office,  the  title  of  a  book,  the  right  whereof  thy 
claim  as  proprietors,  in  the  words  following  to  wit. 

«•  Elements  of  Physiology.  By  A.  Richerand,  Professor  of  the  Faculty  of  Medicine 
'  of  Paris,  Surgeon  in  Chief  of  the  Hospital  of  St.  Louis,  Member  of  the  Aca- 
1  demies  of  Vienna,  Petersburg,  Madrid,  Turin,  &c.  Translated  from  the  French, 
'  by  G.  J.  M.  De  Lys,  M.  D.  Member  of  the  Royal  College  of  Surgeons  in  Lon- 
'  don.  With  Annotations,  by  N.  Chapman,  M.  D.  Professor  of  the  Institutes  and 
'  Practice  of  Medicine  in  the  University  of  Pennsylvania;  copious  Notes  and  an 
'  Appendix,  by  James  Copland,  M.  D.  of  London;  and  additional  notes,  by  John 
'  D.  Godman,  M.  D.  Lecturer  on  Anatomy  and  Physiology.  Fifth  American, 
'  from  the  last  London  Edition." 

In  conformity  to  the  act  of  the  Congress  of  the  United  States,  entitled,  "  An  act 
for  the  encouragement  of  learning,  by  securing  the  copies  of  maps,  charts,  and  books, 
to  the  authors  and  proprietors  of  such  copies,  during  the  times  therein  mentioned."  And 
also  to  the  act,  entitled,  "  An  act  supplementary  to  an  act,  entitled,  "  An  act  for  the 
encouragement  of  learning,  by  securing  the  copies  of  maps,  charts,  and  books,  to  the 
authors  and  proprietors  of  such  copies  during  the  times  therein  mentioned,"  and  extend- 
ing the  benefits  thereof  to  the  arts  of  designing,  engraving,  and  etching  historical  and 
other  prints." 

D.  CALDWELL, 
Clerk  of  the  Eastern  District  of  Pennsylvania* 


, 

\v 


TO 

PHILIP  SYNG  PHYSICK,  M.  D. 

PROFESSOR   OF  ANATOMY  IX  THE  UNIVERSITY  OF  PENNSYLVANIA  ; 

WHO,  BY  HIS  NATIVE  GENIUS, 

HAS  GAINED  A  REPUTATION  BEYOND  THE  POWER  OF  ACCIDENT  J 

WHOSE  PROFESSIONAL  SKILL, 

HAS  LONG  BEEN  A  NATIONAL  BENEFIT  ;  AND  WHOSE  ARDENT 
DESIRE  OF  KNOWLEDGE  IS  ONLY  EQUALLED 

BY  HIS  SOLICITUDE  TO  DIFFUSE  ITS  BLESSINGS, 

THE  FIFTH  AMERICAN  EDITION  OF 
THIS    WORK    IS    MOST    EESPECFULLY 

DEDICATED, 


THE 


AUTHOR'S  ADVERTISEMENT 


TO  THE 


FIFTH  EDITION,* 


IN  preparing  for  the  press  this  Fifth  Edition  of  his  work,  the  Author 
has  carefully  revised  and  corrected  it,  in  all  its  parts,  so  as  to  render  it 
more  worthy  of  the  success  it  has  already  obtained.  The  additions 
which  have  been  made,  will  be  found  not  to  consist  of  idle  discourses,  or 
frivolous  hypotheses.  The  ground-work  and  the  order  are  the  same,  the 
Author  has  merely  added  to  the  mass  of  facts, — supported,  by  additional 
proofs,  the  opinions  which  he  had  advanced, — and  developed  those  parts 
of  his  subject,  which,  from  being  explained  in  too  concise  a  manner, 
might  be  involved  in  some  degree  of  obscurity. 

Among  the  variety  of  opinions  which  Criticism,  oftener  unjust  than  en- 
lightened, has  pronounced,  in  judging  this  work,  there  is  one  which  re- 
quires to  be  refuted,  because  it  proceeds  from  an  erroneous  idea  of  what 
an  elementary  work  should  be.  The  Author,  it  has  been  said  ought  to 
have  contented  himself  with  giving  a  view  of  the  present  state  of  the  sci- 
ence, without  any  additions  of  his  own,  and  he  should  have  abstained 
from  inserting  new  opinions,  which,  until  they  had  received  the  sanction 
of  the  learned  world,  ought  not  to  have  been  introduced  into  an  elemen- 
tary work.  This  objection  may  be  answered,  by  considering  that  modern 
Physiology  being,  in  some  measure,  a  new  and  regenerated  science,  there 
will  be  found,  in  treating  of  it  to  its  full  extent,  many  deficiencies  to  be 
filled  up,  and  many  doctrines  evidently  erroneous,  for  which  truths  are 
to  be  substituted,  which  it  is  of  importance  to  discover.  Lavoisier,  in 
his  Elements  of  Chemistry,  set  forth,  in  a  methodical  order,  truths  which 
he  himself  had  discovered  :  he  introduced  original  ideas,  not  such  as  owe 
an  appearance  of  originality,  to  minute  explanation  of  what  is  already 
known,  or  to  a  general  want  of  erudition,  too  prevalent  in  the  present 
day.  One  of  his  most  illustrious  colleagues,  in  describing  the  state  of 
the  science,  has  likewise  given  a  history  of  his  discoveries  and  labours, 
and  men  of  the  soundest  judgment  ascribe  the  astonishing  progress  of 
chemistry,  in  a  great  measure,  to  the  favourable  circumstance  of  our 
possessing  elementary  works  written  by  the  most  distinguished  chemists. 

*  Published  1811, 


VI  ADV  ERTI S  EM  EX  T . 

The  present  work  has  been  translated  in  England,  in  Spain,  in  Italy? 
in  Germany,  and  men  of  merit  have  not  disdained  the  task  :  amongst 
others,  I  may  mention  Mr.  Robert  Kerrison,  Member  of  the  Royal  Col- 
lege of  Surgeons  in  London,  author  of  a  translation  of  these  Elements 
of  Physiology,  published  in  the  year  1803. 

Since  the  "publication  of  the  Fourth  Edition  of  this  work,  Professor 
Sprengell  has  published  his  Institutes  of  Physiology.5*  The  date  of  that 
new  work,  and  the  well  deserved  reputation^of  its  author,  entitle  it  to  be 
considered  as  a  faithful  account  of  the  state  of  physiological  sciences  in 
Germany.  In  that  work,  the  reader  will  be  astonished  to  find  it  stated 
that  every  thing  in  the  human  body  is  governed  by  polar  influence,  and 
by  the  laws  of  antagonism  ;  that  man  is  in  a  state  of  positive  electricity  ; 
that  his  body  is  formed  chiefly  of  oxygen  :  while  the  female  body  is  in  a 
state  of  negative  electricity,  with  a  superabundant  quantity  of  hydrogen 
in  the  composition  of  its  solids  and  fluids.  Thus,  by  the  premature  ap- 
plication of  a  few  facts,  borrowed  from  the  physico-chemical  sciences, 
the  learned  of  Germany  have  thrown  back  Physiology  into  the  uncertain- 
ty of  conjectures  and  hypotheses. 

*  On  the  other  hand,  Gall,  by  his  anatomical  discoveries  on  the  organi- 
zation of  the  brain  and  nerves,  and  a  few  other  Physiologists,  by  their 
experiments  on  living  animals,  have  been  usefully  employed  in  advanc- 
ing the  progress  of  Physiology.  The  author  has  been  anxious  to  increase 
the  value  of  this  new  edition,  by  adding  to  it  the  result  of  their  obser- 
vations. 

*  Institutiones  Physiologic ce.    Amstelocl.  1809,  2  vols.  8  vo. 


THE  AUTHOR'S  PREFACE. 


THESE  Elements  of  Physiology,  which  contain  an  abstract  of  the  doc- 
trines I  have  taught  for  several  years  past  in  my  public  lesctures,  are 
written  on  the  model  of  the  small  work  on  Physiology  of  the  great  and 
immortal  Haller.  I  am  far,  however,  from  presuming  to  say  that  I  have 
equalled  the  merit  of  a  work,  which,  as  is  remarked  by  a  man  of  the 
highest  ability,*  gave,  when  it  appeared,  a  new  aspect  to  the  science, 
and  commanded  universal  approbation.  If  these  Elements  of  Physiology 
deserve  any  preference  over  that  work,  the  honour  is  not  due  to  the  Au- 
thor, but  to  the  times  in  which  he  writes,  enriched  by  the  progress  of 
the  physical  sciences,  with  a  multitude  of  data  and  results  which  may  be 
said  to  have  rendered  Physiology  altogether  a  new  science. 

It  will  be  easily  perceived,  that  the  plan  I  have  adopted  differs  essen- 
tially from  that  followed  by  several  repectable  physicians ;  and  that  the 
treatises  on  Physiology  most  recently  published,  resemble  the  present, 
only  in  their  title.  In  combining  a  great  number  of  facts,  in  adding  to 
those  already  known,  the  result  of  my  own  observation  and  experience, 
and  in  connecting  them  by  a  method  that  should  unite  accuracy  and 
simplicity,  I  have  had  it  in  view  to  keep  a  due  measure  between  those 
elementary  works,  whose  conciseness  approaches  to  obscurity  and  dry- 
ness,  and  those  in  which  the  authors,  omitting  no  detail,  and  exhausting 
in  a  manner  their  subject,  seem  to  have  written  only  for  those  who  have 
leisure  or  inclination  for  the  profoundest  study. 

Should  any  conceive  that  the  present  undertaking  is  above  the  capacity 
of  my  age,  I  will  say,  even  at  the  risk  of  a  paradox,  that  young  men  are, 
perhaps,  fittest  to  compose  elementary  works  ;  because  the  difficulties 
they  have  encountered  in  the  study,  are  yet  fresh  in  their  memory,  as  well 
as  the  steps  which  they  have  taken  to  overcome  them  ;  and  further,  be- 
cause their  recent  experience  points  out  to  them  the  defects  and  advan- 
tages of  the  different  methods  of  other  instructors  ;t  so  that  he,  who  in 
the  shortest  lapse  of  time,  has  carried  to  the  greatest  extent  his  own  ac- 
quisition of  sound  knowledge,  will,  in  some  respects,  be  the  best  guide  to 
his  successors,  in  the  difficult  and  perplexing  parts  of  elementary  study. 

In  the  composition  of  the  work,  I  have  borne  constantly  in  mind  the 
necessity  tf  sacrificing  elegance  to  clearness,  which  I  know  to  be  the 
most  important  merit  of  an  elementary  treatise.  Further,  I  have  through- 
out followed,  I  believe,  the  same  arrangement  in  the  succession  of  the 
subjects,  and  applied  to  the  science  of  living  man,  the  principle  of  the 
Association  of  ideas,  so  well  developed  by  Condillac,  (in  his  Treatise  on 
the  Art  of  Writing,)  and  to  which  that  philosopher  has  shown,  that  all 
the  rules  of  the  art  are  to  be  referred.  Notwithstanding  the  rigorous  law 
to  which  I  have  subjected  myself,  I  have,  after  the  example  of  the  an- 
cients, and,  among  the  moderns,  of  Bordeu,  and  of  several  other  physi- 
cians and  physiologists  of  equal  celebrity,  thought  myself  justified  in  em- 
ploying, when  I  felt  it  necessary,  metaphorical  expressions  ;  because,  as 
has  been  correctly  observed  by "a  justly  celebrated  writer,  if  conciseness 
do  not  consist  in  the  art  of  reducing  the  number  of  words,  still  less  does 
it  consist  in  depriving  language  of  imagery.  The  conciseness  which  is 
to  be  envied  is  that  of  Tacitus,  at  once  eloquent  and  energetic  ;  and,  far 
from  any  fear  that  imagery  should  injure  that  deservedly  admired  com- 

*  "  When  Haller  published  his  Printce  Unfa;  Pbysioloxite,  which  he  valued  most  of  all  his  works,  a  consider- 
able sensation  was  excited  in  the  schools.  In  works  on  the  same  subject,  it  was  customary  to  find  long  disser- 
tations, almost  always  void  of  proof,  extraordinary  opinions,  or  brilfiant  fictions.  It  was  matter  of  wonder,  that 
in  Haller  swr.rk,  there  should  be  found  only  numerous  iaets,  precise  details,  and  direct  inferences,  &c."— 

t"  1  'he  best  order  in  which  truth  can  be  set  forth,  is  that  in  which  it  might  naturally  have  been  discovered ; 
tor,  the  surest  method  of  instructing  others,  is  to  lead  them  along  the  path  which  we  ourselves  have  followed, 
in  our  own  instruction,  in  this  way,  we  shall  seem  not  so  much  to  lay  before  them  our  own  knowledge,  as 
to  set  themselves  on  the  suavch  and  discovery  of  unknown  truthB."--£0/n£/ftif. 


Vlii  PREFACE. 

pression  of  style,  figurative  expressions  are,  indeed,  those  which  comprise 
in  fewest  words  the  greatest  sum  of  ideas.* 

Those  who  insist  on  meeting  in  a  work  on  Physiology,  with  a  romance 
instead  of  the  history  of  the  animal  economy,  will,  no  doubt,  reproach  me 
with  having  entirely  neglected  a  great  number  of  hypotheses,  on  the  uses 
of  organs,  ingenious  or  absurd  ;  with  having  omitted,  for  example,  while 
speaking  of  the  spleen,  to  mention  the  opinion  which  considers  that  viscus 
as  the  seat  of  mirth  and  laughter ;  with  having  said  nothing  of  the  opinion 
of  those  authors,  who  conceive  it  to  maintain  the  equilibrium  of  the  two 
hypochondria,  by  counterpoising  the  liver  ;  nor  even  of  the  doctrine  of 
tne  ancients  who  ascribed  to  it  the  secretion  of  the  atra  bilis,  &c.  To 
recall  such  errors  for  the  sake  of  elaborate  refutation,  would  be  wasting 
much  precious  time  in  idle  discussions,  and  possessing,  as  Bacon  calls  it, 
the  art  of  making  one  question  bring  forth  a  thousand,  by  answers  more 
and  more  unsatisfactory.  I  have  chosen  to  forego  all  such  vain  parade, 
from  a  clear  conviction,  that  works  of  merit  are  as  often  distinguished  by 
some  things,  that  are  not  to  be  found  in  them,  as  by  those  they  do  contain. 

Several  authors,  in  treating  of  the  science  of  man,  have  indulged  them- 
selves in  frequent  excursion  into  the  vast  field  of  accessory  sciences,  and 
have,  without  necessity,  incorporated  in  their  works  whole  chapters  on 
air,  on  sound,  on  light,  and  other  subjects,  which  belong  to  the  depart- 
ment of  natural  philosophy  and  chemistry.  Haller  himself  is  not  entire- 
ly free  of  blame,  for  having  discredited  physiology  by  this  borrowed  dis- 
play. I  have  introduced  only  such  general  ideas  of  the  subject,  as  were 
absolutely  necessary  to  render  my  own  intelligible,  and  were,  indeed, 
too  closely  connected  with  it,  to  admit  of  separation. 

One  of  the  principal  faults  of  writers  on  physiology  is,  that  they  are  apt 
to  fall  into  frequent  repetitions  5  and  that  fault  is  often  owing  to  the  diffi- 
culty of  settling,  satisfactorily,  the  limits  of  action,  which  are  mutually 
connected  and  dependent  among  themselves,  and  running  into  each  other, 
like  those  that  are  cawied  on  in  the  animal  economy. 

"  In  composition,  one  should  avoid  prolixity,  because  it  is  fatiguing  to 
"  the  mind  ;  digressions,  because  they  divert  the  attention  ;  frequent  divi- 
"  sions  and  sub-divisions,  because  they  are  perplexing  ;  and  repetitions, 
"because  they  are  oppressive.  What  has  been  once  said,  an<J  in  its  pro- 
"  per  place,  is  clearer  than  if  several  times  repeated  elsewhere,  "t  In 
following  these  precepts,  (and  they  cannot  be  too  much  attended  to,)  one 
raav»  it  is  true,  incur  the  risk  of  being  thought  superficial,  by  superficial 
reaclers,  who  form  their  opinion  of  a  work  from  the  perusal  of  a  single 
chapter ;  but  a  most  ample  compensation  will  be  found  in  the  opinion  of 
those,  who  choose  to  be  thoroughly  acquainted  with  a  work,  before  they 
pass  on  it  their  final  judgment. 

After  having  stated  in  what  spirit  this  work  has  been  written,  I  may 
say  something^  of  the  motives  which  have  led  to  its  publication.  I  would 
mention  in  the  first  place,  the  advantage  which,  it  might  be  expected, 
would  accrue  to  the  science,  and  to  those  who  are  engaged  in  its  pursuit ; 
and,  in  the  next  place,  the  satisfaction  which  study  has  in  store  for  him, 
who  bestows  on  it  the  time  he  can  snatch  from  the  laborious  practice  of 
our  art.  In  his  short  intervals  of  leisure  from  public  instruction  and 
from  professional  duty,  left  to  himself  and  his  own  thoughts,  in  the  silence 
of  study,  and  in  the  calm  of  meditation,  he  looks  down,  with  an  eye  of 
pity,  on  those,  who  drag  on,  through  the  lowest  intrigues,  a  despicable  ex- 
istence, and  there  finds  his  consolation  against  the  endless  vexations  that 
are  prepared  for  him  by  supercilious  ignorance,  and  jealous  mediocrity. 

*"  Df  la-Literature  consideie  danssts  rapports  avec  les  Institutions  Sociaies  per  Madame  de  Stael-Holstein, 
•f  Condillac  Essai  sin-  rOrigine  des  Cormoissanees  humaines,  seronde  partie,  sect.  ii.  chap.  iv. 


PRELIMINARY  DISCOURSE. 


PHYSIOLOGY*  is  the  science  of  life.  The  term  life  is  applied  to  an  ag- 
gregate of  phenomena,  which  manifest  themselves  in  succession,  for  a 
limited  time,  in  organized  bodies.  Combustion  is  likewise  only  a  combina- 
tion of  phenomena;  oxygen  unites  with  the  substance  which  is  burning, 
caloric  is  disengaged  from  it;  affinity  is  the  cause  of  these  chemical  phe- 
nomena, as  attraction  is  the  cause  of  the  phenomena  of  Astronomy,  and 
in  the  same  manner  as  the  sensibility  and  contractility  of  living  and  or- 
ganized bodies  are  the  primary  causes  of  all  the  phenomena  which  such 
bodies  exhibit —  phenomena,  which  in  their  union  and  aggregate  succes- 
sion constitute  life. 

The  false  notions  which  have  been  entertained  on  the  subject  of  life,  and 
the  vague  definitions  which  have  been  given  of  it,  are  to  be  accounted  for, 
by  considering  that  physiologists,  instead  of  regarding  life  as  a  simplere- 
sult  have  mistaken  it  for  the  properties  of  life.  These  last  are  causes; 
the  first  is  merely  an  effect,  more  or  less  complex  :  and,  as  the  spring  of 
a  watch,  or  rather  the  elasticity  of  that  spring,  determines  by  the  mere 
action  of  the  wheels,  the  motion  of  the  hands,  and  all  the  phenomena  of 
which  the  machine  is  capable;  so  the  vital  properties  acting  by  the  or- 
gans produce  alithose  effects,  which  in  their  combination  constitute  life.t 
These  effects  are  more  or  less  numerous,  according  to  the  number  of  the 
organs;  they  become  more  rapid  too  in  their  succession,  and  life  more  ac- 
tive, with  the  increase  of  energy  in  the  vital  properties ;  precisely  as  the 
motions  of  a  watch  become  more  complicated,  stronger  or  quicker,  ac- 
cording to  the  greater  tension  of  the  spring,  or  the  increased  number  of 
the  wheels.  Sensibility  and  contractility,  are  to  be  ranked  amorg  primary 
causes,  of  whose  existence  and  laws  we  acquire  a  knowledp^froni  obser- 
vation, but  whose  essence  eludesour  investigation^,  and^'dl  probably  re- 
main for  ever  beyond  its  reach. 

§  I.  OF  NATURAL  BEINGS. 

The  vast  domain  of  nature  is  divided  between  two  classes  of  beings. 
Inorganic  beings,  possessing  merely  the  common  properties  of  matter; 
organic  and  living  beings,  obeyingparticular  laws,  though  subjected  to  the 
general  laws  which  regulate  the  universe.  Each  of  these  two  grand  di- 
visions is  naturally  divided  into  t\no  classes;  we  meet  with  inorganic  bo- 
dies under  the  form  of  elementary  substances',  simple  and  not  capable  of 

*  Anatomy  is  the  science  of  organization, 
-f  See  Appendix,  Note  A. 

*  It  would  be  wrong  to  infer,  from  our  ignorance  of  the  nature  of  the  vital  proper- 
ties, that  physiology  is'an  uncertain  Science.    Its  certainty  in  that  point  of  view,  5^  equal 
to  that  of  other  parts  of  natural  philosophy.     The  chemist,  who  explains  all  his  com- 
binations by  referring  them  to  the  principle  of  affinity,  and  the  astronomer,  who  finds  in 
attraction  the  cauee  that  rules  the  universe,  are  absolutely  ignorant  of  the  uature  of 
those  properties. — Authors  Note. 

B 


10 

analysis;  or  else  under  the  form  of 'mixed  substances,  compound,  and  ad- 
mitting of  decomposition.  Thus,  too,  organized  beings  exist  under 
two  very  different  forms  of  life,  which  distinguish  them  into  vegetables 
and  animals. 

The  first  general  conception  with  which  we  ought  to  enter  upon  this 
comprehensive  study  of  nature,  is  the  mutual  dependence  of  those  beings, 
which,  in  their  co-ordinate  whole,  compose  the  system  of  nature;  a  de- 
pendence which  requires  for  each  the  simultaneous  existence  of  all.  Thus 
a  vegetable  derives  its  nourishment  from  inorganic  bodies*,  and  alters 
their  inert  substance,  which  is  unfit  for  the  food  of  animals,  unless  it  has 
previously  undergone  the  influence  of  vegetable  life. 

§  II.  OF  THE  ELEMENTS  OF  BODIES. 

Another  consideration,  of  equal  importance  with  the  former,  is  the  con- 
vertibility of  all  those  substances  so  different  from  one  another,  and  their 
capacity  of  being  reduced  to  a  small  number  of  simple  substances,  called 
elements.  The  ancient  doctrine  of  Aristotle,  relative  to  the  four  elements, 
still  prevailed  in  the  schools,  with  a  few  modifications,  which  it  had  re- 
ceived from  the  chemists,  when  the  "  Pneumatistsf"  demonstrated  by 
their  beautiful  experiments,  that  three,  at  least,  of  these  pretended  prin- 
ciples of  bodies,  air,  water,  and  earth,  far  from  being  simple  substances, 
were  evidently  formed  by  the  union  and  combination  of  several  others ; 
that  atmospherical  air,  for  example,  far  from  being  an  homogeneous  fluid, 
was  composed  of  many  different  gazes,  and  that  in  its  purest  state,  it  con- 
tains at  least  two  very  distinct  principles,  oxygen  and  azote;  that  water 
Is  a  compound  of  oxygen  and  hydrogen,  and  that  earth  contains  clay, 
lime,  silex.  See. 

We  have  seen  added  in  the  present  day,  to  the  number  of  the  elements 
or  simple  substances,  several  which  were  not  considered  as  such,  at  the 
tim^when  natural  philosophers,  misled  by  erroneous  metaphysical  doc- 
trines, Uad  created  out  of  their  imagination?,  beings  of  the  existence  of 
which  they  could  find  no  proof.  There  is  every  reason  to  believe,  that  the 
number  of  substances  not  admitting  of  decomposition,  limited  at  present 
to  forty-four,  ms,y  hereafter  be  increased  or  diminished,  by  the  discovery 
of  new  principles  \\\  simple  substances,  or  of  new  elements  in  compound 
bodies,  which  have  hitherto  eluded  the  investigation  of  chemists.  What- 
ever may  be  the  success  ^f  their  inquiries,  of  which  it  is  impossible  to 
foresee  the  results,  or  to  fix  the  limits,  there  is  reason  to  believe,  that  it 

*  MJBBEL,  in  his  treatise  on  Vegetable  Anftomy  and  Physiology,  observes,  "  that 
plants  have  the  power  of  deriving1  nourishment/from,  inorganic  matter,  which  is  not  the 
case  with  animals,  who  feed  on  animals  and  vegetables,  or  on  both;  but  are  never  nou- 
rished on  earths,  salts  and  airs."  Richerand  las  adopted  the  plausible  opinion  of  Mir- 
bel.  Farther  inquiry  might,  however,  have  shown  them  that  «  earths  and  salts"  furnish 
as  little  direct  nourishment  to  plants  as  to  animals.  Indeed  it  may  be  observed,  that  the 
vegetable  kingdom  derives  the  chief  part  of  its  iood  from  dead  animal  and  vegetable 
matters — which,  although  they  contain  both  "  earths  and  salts"  cannot  be  either  rank- 
ed under  these  substances,  or  even  classed  with  them. —  Copland. 

j  This  is  the  name  given  to  the  school  of  modern  chemistry,  because  it  originated 
from  the  discoveries  made  relative  to  the  nature  of  air  and  elastic  fluids.  It  must  be 
acknowledged,  to  the  credit  of  metaphysics,  that  the  old  errors  were  forsaken,  only  at 
the  period  when  chemists  were  thoroughly  convinced  of  this  truth,  that  every  ide'a  is 
obtained  through  the  medium  of  the  senses,  and  that  nothing  is  to  be  admitted*  beyond 
what  they  demonstrate  in  actual  experiment. — Authors  Mtc, 


II 

will  ever  be  denied  us,  to  arrive  at  a  knowledge  of  the  true  elements  oi 
bodies,  and  that  many  of  those  substances,  which  the  imperfection  of  our 
means  of  decomposition  or  analysis  obliges  us  to  consider  as  such,  are 
frequently  compound  substances,  and  subject  to  their  laws. 

After  what  has  been  stated  on  the  elements  or  constituent  principles  of 
substances,  let  us  now  see  in  what  manner  the  combination  of  these  ele- 
ments gives  existence  to  all  beings,  and  what  are  the  general  differences 
existing  among  the  great  classes  into  which  they  are  divided. 

§  III.    DIFFERENCES    BETWEEN   ORGANIZED    AND    INOR- 
GANIZED  BODIES. 

Much  attention  has  been  bestowed  of  late  on  the  difference  which  exists 
between  organized  and  inorganized  bodies.  The  latter  have  been  observ- 
ed to  be  very  different  from  those  which  are  endowed  with  life,  in  the  ho- 
mogeneous nature  of  their  substance,  in  the  complete  independence  of 
their  molecules,  each  of  which,  according  to  the  observation  of  Kant,  has 
in  itself  causes  to  account  for  its  peculiar  mode  of  existence,  in  that  pow- 
er of  resisting  decomposition  which  they  owe  to  the  simplicity  of  their 
structure,  and  in  the  absence  of  those  peculiar  powers  which  free  organic 
bodies  from  the  absolute  dominion  of  physical  laws.  The  characters 
which  distinguish  organized  beings  from  inorganized  substances,  are,  the 
multiplicity,  and  volatility  of  their  elements,  the  necessary  union  of  flu- 
ids and,solids,  the  nutrition  and  developement  from  the  diffusive  combina- 
tion, while  the  growth  of  inanimate  bodies  takes  place  from  the  mere 
juxtaposition  of  particles,  theorigin  of  living  bodies  in  generation,  their 
destruction  in  deathf.  We  are  about  to  enter  into  a  detail  of  those  cha- 
racters, to  appreciate  all  their  differences,  for  knowledge  is  to  be  acquir- 
ed only  by  comparison;  and  the  greater  our  accuracy  in  comparing,  the 
more  precise  and  extensive-will  be  the  knowledge  we  obtain.  Several  mo- 
dern authors  have  proved,  that  it  is  impossible  to  obtain  an  accurate  idea 
of  life,  except  by  comparing  those  bodies  which  are  endowed  with  it, 
with  those  in  which  life  has  never  existed,  or  has  ceased  to  exist.  This 
comparison,  I  hope,  will  be  fruitful  in  interesting  results,  and  will  furnish 

*  The  subjoined  table  by  Magendie,  displays  very  satisfactorily  the  most  perceptible 
differences  existing  between  the  two  great  classes  of  beings. — Godman. 

INORGANIC    BODIES. 

Form. — Angular.     Volume  indeterminate. 

Composition. — Sometimes  simple.  Rarely  formed  of  more  than  three  elements.  Con- 
stant. Each  part  can  exist  independent  of  the  rest.  Capable  of  decomposition  and 
recomposition. 

Laias  governing  them. — Entirely  submissive  to  the  laws  of  attraction  and  chemical 
affinity. 

LIVING    ORGANIZED    BODIES. 

Form. — Rounded.    Volume  determinate. 

Composition.— Never  simple.  Having  at  least  four  elements,  frequently  eight  or  ten. 
Variable.  Each  part,  more  or  less,  dependent  on  the  rest.  Capable  of  decomposition, 
but  not  of  recomposition. 

Laws  governing  them. — Partially  submissive  to  the  law*  of  attraction  and  chemical 
affinity.  Partly  controuled  by  an  unknown  power. 

Of  living  bodies  there  are  two  classes. 

Vegetables — Which  are  fixed  to  the  soil.  Have  carbon  as  the  chief  base  of  their  com- 
position. Composed  of  four  or  five  elements.  Receive  their  aliment  ready  prepared 
from  around  ttiem. 


12 

several  useful  considerations,  immediately  applicable  to  the  knowledge 
of  man. 

The  first  remarkable  difference  between  organized  and  inorganized 
bodies,  is  to  be  found  in  the  homogeneousness  of  the  latter,  and  the  com- 
pound nature  of  the  former.  Let  a  block  of  marble  be  broken,  each 
piece  will  be  perfectly  similar  to  the  rest,  there  will  be  no  differences 
among-  them,  but  such  as  relate  to  size  or  shape.  Break  down  the  frag- 
ments, each  grain  will  contain  particles  of  carbonate  of  lime,  which  will 
be  throughout  the  same.  On  the  other  hand,  the  division  of  a  vegetable 
or  an  animal,  shows  parts  heterogeneous  or  dissimilar.  In  different 
parts  there  will  be  found  muscles,  bones,  arteries,  blossoms,  leaves, 
bark,  pith,  Sec. 

Organized  beings  cannot  live  or  exist  in  their  natural  condition,  unless 
solids  and  liquids  enter  at  once  into  their  composition.  The  co-existence 
of  these  two  elements  is  necessary;  and  living  bodies  always  contain  a 
liquid  mass  more  or  less  considerable,  and  incessantly  agitated  by  the 
motion  of  the  solid  and  living  parts.  It  is  in  fact  impossible  to  conceive 
life  existing,  without  a  complicated  combination  of  solids  and  fluids  ;  and 
xvithout  admitting  in  the  former,  the  faculty  of  being  affected  by  impressions 
from  the  latter,  and  the  power  of  acting  in  consequence  of  those  impres- 
sions. The  water  which  penetrates  into  mineral  substances,  does  not 
form  a  necessary  part  of  them,  and  one  cannot  adduce  in  proof  of  the 
existence  of  liquids  in  that  class  of  substances,  the  water  of  crystalliza- 
tion, though  intimately  combined,  and  rendered  solid  in  the  crystallized 
substances. 

These  inorganic  and  homogeneous  substances,  formed  of  particles  simi- 
lar to  one  another,  when  resolved  by  decomposition  into  their  last  ele- 
ments, possess  a  great  simplicity  of  inward  nature.  Among  them  are 
ranked  all  the  substances  which  do  not  admit  of  analysis;  the  mineral 
compounds  are  often  binary,  as  the  greater  part  of  saline  substances; 
sometimes  they  are  ternary,  but  seldom  quaternary;  while  the  most  sim- 
ple vegetable  contains  at  least  three  constituent  principles,  oxygen,  hy- 
drogen, and  carbon,  and  no  being  possessed  of  life,  consists  of  less  than 
four,  oxygen,  hydrogen,  carbon  and  azote.  In  the  degree  of  composition, 
nature  appears  therefore  to  rise  in  gradations,  from  the  mineral  to  the 
vegetable,  and  from  the  latter  to  the  animal  kingdom.  The  complicated 
nature  of  die  latter,  and  the  multiplicity  of  their  elements  account  for  their 
tendency  to  alteration.  Minerals  are  not  subject  to  change,  unless  they 
are  acted  upon  by  external  causes.  Endowed  with  a  vis  inertiae,  they 
continue  in  one.  condition  without  change.  The  state  of  organized  bodies 
is  incessantly  varying.  Their  internal  parts  contain  an  active  laboratory, 
in  which  a  number  of  instruments  are  constantly  transforming  into  their 
own  substance,  nutritious  particles.  Besides  that  tendency  to  alteration 
in  living  animals  and  vegetables,  when  deprived  of  life,  they  become  de- 
composed, by  a  process  of  fermentation,  which  begins  in  their  internal 
parts,  and  by  which  their  nature  is  changed  in  proportion  to  the  com- 
plication of  iheir  structure,  and  the  greater  number  and  volatility  of  their 
constituent  principles. 

All  the  parts  of  a  living  body,  whether  of  an  animal  or  a  vegetable, 

Jlnimals — Have  the  power  of  locomotion.  Have  azote  for  the  base  of  their  composi- 
tion. Often  composed  of  eight  or  ten  elements.  Are  forced  to  act  on  their  aliment  to 
fit  it  for  nourishing1  them.  - 


13 

have  a  natural  tendency  to  a  common  object,  the  preservation  of  the  in- 
dividual and  of  the  species:  each  of  the  organs,  though  provided  for  a 
peculiar  action,  concurs  in  this  object;-  and  life  in  general,  or  life  proper- 
ly so  called,  is  the  result  of  that  series  of  concurring  and  harmonic  actions. 
On  the  contrary,  each  part  of  an  inorganic  mass  is  independent  of  the 
other  parts,  to  which  it  is  united,  only  by  the  force  or  affinity  of  aggrega- 
tion. When  such  a  part  is  separated  from  the  rest,  it  maintains  all  its 
characteristic  properties,  and  differs  only  by  its  size  from  the  mass  to 
which  it  belongs. 

Among  animals  and  vegetables,  all  the  individuals  of  the  same  class 
appear  to  have  been  formed  after  the  same  model;  their  parts  are  equas 
in  number,  and  resemble  each  other  in  colour;  their  differences  are  slight 
and  evanescent.  The  forms  peculiar  to  organized  beings  are  therefore 
invariably  determined,  and  when  nature  departs  from  them,  she  never 
does  so,  to  such  a  degree,  as  in  the  shapes  of  minerals.  The  veins  of 
mines  are  never  precisely  alike,  as  the  leaves  of  vegetables  or  the  limbs 
of  animals.  Crystals  formed  from  similar  substances,  assume  very  dif- 
ferent shapes,  equally  distinct  and  precise.  Carbonate  of  lime,  for  ex- 
ample, assumes  according  to  circximstances  the  shape  of  a  rhomboid,  that 
of  a  six-sided  regular  prism,  that  of  a  solid,  terminated  by  twelve  scalene 
triangles,  that  of  a  different  dodecahedron  with  pentagonal  faces,  S&c.  as 
may  be  seen  at  large  in  the  writings  of  Hiiuy. 

A  powerful  inward  cause  seems  to  arrange  the  constituent  parts  of  ani- 
mal and  vegetable  bodies,  by  a  determinate  rule,  in  such  a  manner  that 
they  present  a  surface,  more  or  less  completely  rounded.  Minerals  often 
take  their  form  from  external  bodies,  and  when  an  especial  force  assigns 
it  to  them,  as  in  crystals,  their  surfaces  are  flat  and  angular.  When  the 
crystallization  is  disturbed,  and  the  molecules  of  the  crystals  are  driven 
tumultuously  together,  the  geometrical  form  is  impaired,  the  parts  are 
rounded  which  would  have  been  terminated  by  angles,  if  a  slow  and  tran- 
quil crystallization  had  allowed  of  regular  aggregation;  and  as  Hauy 
has  remarked,  these  waving  outlines,  these  roundings,  so  frequent  in  ve- 
getables and  plants,  where  they  belong  to  beauty  of  form,  are,  in  mine- 
rals, indication  of  defects.  True  beauty,  in  these  beings,  is  characterized 
by  the  straight  line,  and  it  is  on  good  grounds  that  Rome  de  Lisle*  has 
said  of  this  sort  of  line,  that  it  seems  to  have  an  especial  determination 
to  the  mineral  kingdom. 

Amongst  all  the  characteristics  which  distinguish  the  two  great  divi- 
sions of  natural  bodies,  the  most  absolute,  and  the  most  palpable,  is  that: 
which  is  drawn  from  the  manner  of  growth  and  of  nourishment.  Inor- 
ganic bodies  grow  only  by  accretion,  that  is,  by  the  accession  of  new  lay- 
ers to  their  surface,  whilst  the  organic,  in  virtue  of  its  vital  powers,  re- 
ceives into  intimate  combination,  and  is  penetrated  and  pervaded,  by  the 
substance  it  assimilates  to  itself.  In  animals  and  plants,  nutrition  is  the 
effect  of  an  internal  mechanism :  their  growth  is  a  developement  from 
within.  In  minerals,  on  the  contrary,  growth  cannot  claim  the  name  of 
developement:  it  goes  on  externally,  by  successive  addition  of  new  lay- 
ers; it  is  the  same  being,  assuming  other  dimensions,  whilst  the  organic 
body  is  renewed  in  its  growthf. 

*  Christallographie.    Tom.  I.  p.  94. 

f  The  organic  body,  is  "  renewed"  by  the  absorption  of  the  old  and  the  deposition  of 
new  matter,  while  the  inorganic  always  retains  the  same  matter  internally,  and  only 
grows  externally,  by  superposition. — Godman. 


14 

Living  bodies  spring  from  a  germ,  which  at  first,  was  part  of  another 
being,  from  which  it  detaches  itself,  for  the  sake  of  its  own  developement 
and  growth.  From  the  first,  they  are  already  aggregates.  Inorganic 
bodies  have  no  germ :  they  are  made  up  of  distinct  parts  brought  toge- 
ther; they  have  no  birth,  but  a  multitude  of  molecules,  collecting  into 
one,  compose  masses  of  various  bulk  and  figure. 

Organized  bodies  alone  can  die;  all  have  a  duration,  determined  by 
their  own  nature ;  and  this  duration  is  not  like  that  of  minerals,  propor- 
tioned' to  the  bulk  and  density :  for  if  man  has  not  the  life  of  the  oak, 
whose  substance  much  exceeds  his  in  density,  neither  does  he  equal  the 
life  of  many  animals,  such  as  fishes,  whose  flesh  is  of  inferior  consist- 
ence to  his  own:  and  he  lives  longer  than  the  large  quadrupeds,  though 
his  bulk  is  less. 

Finally,  inorganic  are  essentially  distinguished  from  organic  bodies,  by 

the  want  of  these  peculiar  powers  or  properties  of  living  nature:  powers, 

'Which  uphold  the.  equilibrium  of  the  whole  system  of  nature,  as  I  shall 

explain  more  at  large,  when  I  have  considered  the  differences  that  mark 

i    the  two  divisions  of  the  organic  kingdom,  vegetables  and  animals. 

§  IV.   DIFFERENCES  BETWEEN  VEGETABLES  AND  ANI- 
MALS. 

These  are  much  fewer,  less  absolute,  and  therefore  more  difficult  to  es- 
tablish. There  is.  in  fact,  very  little  difference  between  a  zoophyte,  and 
a  plant,  and  there  is  a  much  wider  difference  in  their  internal  oaconomy, 
between  man,  who  stands  at  the  height  of  the  animal  scale,  and  the  poly- 
pus on  its  lowest  line,  than  between  the  polypus  and  a  plant.  There  lies 
between  organized  and  inorganic  bodies,  a  space,  which  isnot  to  be  filled 
up  by  figured  stones,  nor  by  lithophytes,  nor  by  crystals,  in  which  some 
naturalists  have  thought  they  saw  a  beginning  of  organization.  Whilst, 
at  the  extremity  of  the  animal  chain,  are  found  beings,  fixed,  like  plants, 
on  the  spot  of  their  birth,  sensitive  and  contractile,  like  the  sensitive  and 
some  other  plants,  and  reproduced  like  them  from  slips.  Yet  we  are 
able  to  state  some  differences,  sufficiently  marked,  to  assign  to  the  ve- 
getable kind  a  character  of  their  own,  which  will  not  suit  the  individuals 
of  either  of  the  other  kingdoms. 

Their  nature,  more  complex  than  that  of  minerals,  is  Jess  so  than  that 
of  animals:  the  proportion  of  the  solids  to  the  liquids,  is  greater  than  in 
these  last  :  accordingly  they  retain,  long  after  death,  their  form  and  bulk, 
only  that  they  grow  lighter.  The  solids  are,  in  man,  nearly  a  sixth  of 
the  whole  body  :  his  carcase,  remains  decomposed  by  putrefaction,  a  lit- 
tle earth,  arid  a  light  skeleton,  when  the  ground  and  the  air  have  drawn 
from  it  all  its  juices.  A  tree,  on  the  contrary,  is  more  than  three  parts 
of  its  substance,  solid  wood.  It  has  been  dead  for  ages,  and  yet  in  our 
buildings,  it  preserves  its  form  and  size,  though  by  drying  it  has  lost  a 
little  of  its  weight. 

Their  constituent  principles,  as  they  are  less  in  number,  are  also  less 
diffusable.  In  fact,  azote,  which  is  predominant  in  animal  substances,  is  a 
gaseous  and  volatile  principle,  whilst  carbon,  the  base  of  vegetable 
substance,  is  fixed  and  solid.  This  circumstance,  added  to  the  smaller 
quantity  of  their  liquids,  explains  the  long  duration  after  death,  of  ve- 
getable substances. 


15 

But  of  all  the  characteristics  which  have  been  employed  in  estabteih- 
ing  the  limits  of  animal  and  vegetable  nature,  there  is  one  quite  sufficient 
to  distinguish  these  two  great  classes  of  beings,  but  which  has  not  been 
allowed  the  weight  it  deserves. 

The  zoophyte,  which,  fixed  to  a  rocky  habitation,  cfcnnot  change  its 
place,  is  confined  to  partial  movements,  that  certain  plJnts  possess,  and 
besides,  has  not  that  sensitive  unity,  so  remarked  in  man,  and  in  the  ani- 
mals who  nearest  resemble  him  in  their  organization:  the  zoophyte, 
whose  name  indicates  an  animal-plant,  is  totally  separated  from  all  be- 
ings of  the  vegetable  kingdom,  by  the  existence  of  a  cavity,  in  which  ali- 
mentary digestion  is  carried  on,  a  cavity  by  the  surface  of  which  is  effected 
an  absorption,  an  imbibition,  far  more  active  than  that  which  takes  place  by 
the  external  surface  of  the  body.  From  this  shapeless  animal,  up  to  raan? 
nutrition  is  effected  by  two  surfaces,  and  especially  the  internal,  whilst 
in  the  plant,  nutrition,  or  rather  the  absorption  of  nutritive  principles,  is 
only  by  the  external  surface*. 

Every  animal  may  be  considered,  in  extreme  abstraction,  as  a  nutritive 
tube,  open  at  the  extremities!;  the  whole  existence  of  the  polypus  seems 
reduced  to  the  act  of  nutrition,  as  its  whole  substance  is  employed  in  the 
formation  of  an  alimentary  tube,  of  which  the  soft  parietes,  extremely 
sensible  and  contractile,  are  busied  in  appropriating  to  themselves,  by  a 
sort  of  absorption,  the  substances  which  are  brought  into  it.  From  the 
worm  up  to  man,  the  alimentary  canal  is  a  long  tube,  open  at  the  extre- 
mities; at  first,  only  of  the  length  of  the  body  of  the  animal,  not  bent  at 
all  in  passing  from  the  head  to  the  tail,  and  carried  on  towards  the  mouth, 
and  towards  the  anus,  with  the  external  covering  of  the  body,  but  soon 
returning  upon  itself,  and  stretching  out  into  length,  far  beyond  that  of 
the  body  which  contains  it. 

It  is  in  the  thickness  of  the  pari0tes  of  this  animated  tube,  betwixt  the 
mucous  membrane  that  lines  it  inwardly,  and  the  skin  with  which  this 
membrane  is  continuous,  that  all  the  organs  are  placed,  which  serve  for 
the  transmission  and  elaboration  of  fluids,  together  with  the  nerves,  the 
muscles,  in  short,  all  that  serves  for  the  carrying  on  of  life.  As  we  rise, 
from  the  white-blooded  animals,  to  the  red  and  cold-blooded,  from  these 
to  the  warm-blooded,  and  irom  these  to  man,  we  see  a  progressive  multi- 
plication of  the  organs  that  are  contained  within  the  thickness  of  the  pa- 
rietes of  the  canal: — If  we  follow,  on  the  other  hand,  the  descending  scale, 
v/e  see  this  structure  gradually  simplified,  till  we  arrive  at  last  at  the 
polypus,  and  find  in  it  only  the  essential  part  of  animal  existence.  The 
simplicity  of  its  organization  is  such,  that  it  may  be  turned  inside  out, 
and  the  external  be  made  the  internal  surface;  the  phenomena  of  nutri- 
tion, which  are  the  whole  life  of  the  animal,  go  on,  from  the  close  ana- 
logy between  the  two  surfaces;  unlike  to  man  and  the  greater  part  of 
animals,  in  whom  the  skin  and  the  mucous  membranes,  though  growing 
into  e4k.h  other,  though  linked  by  close  sympathies,  are  far  from  possess- 

*  This  most  prominent  characteristic  of  animal  organization  was  lirst  pointed  out  by 
Boerhaave,  anu  afterwards  insisted  on  by  Dr.  Alston  of  Edinburgh,  and  recently  by  Mr. 
A.  T.  Thomson,  in  his  excellent  work  on  the  Elements  of  Botanv. — Copland. 

f  Lacepzde,  Histoire  Naturelle  des  Poissons,  torn  1.  There  may  be  brought  against 
ibis  principle,  the  instance  of  some  zoophytes,  such  as  sponges,  &c.;  but  do  these  bo- 
dies really  belong  to  the  animal  kingdom  ?  and  should  not  we  be  warranted  in  rejecting1 
them,  by  the  want  of  the  alimentary  cavity,  the  essential  characteristic  of  animal  exist- 
in  ce  ? — Author's  Jiote- 


16 

ing  a  complete  analogy  of  structure,  or  a  capacity  for  the  interchange 
of  functions, 

Man,  then,  and  the  whole  animal  kind,  carry  about  within  themselves, 
the  supply  of  their  subsistence;  and  absorption,  by  an  inward  surface,  is 
their  distinguishing  characteristic.  It  is  inaccurate  to  ascribe  to  Boer- 
haave  the  comparison  of  the  digestive  system  of  animals,  to  the  soil  in 
\vhich  plants  suck  up  the  juices  that  feed  them,  and  the  chylous  vessels, 
to  real  internal  roots.  I  find  the  same  thought  well  expressed*  in  the 
work  on  humours,  which,  justly  or  falsely,  bears  the  name  of  Hippo- 
crates. Q?iemadmodum  terrx  arboribus,  ita  animalibus  ventriculus. 

The  digestive  tube,  that  essential  part  of  every  animal,  is  the  part  of 
which  the  existence  and  action  are  the  most  independent  of  the  concur- 
rence of  the  other  organs,  and  to  which  the  properties  of  life  seem  to  ad- 
her;,  if  one  may  say  so,  with  most  force.  Hallerf  who  has  made  so  many 
and  such  interesting  inquiries  into  the  contractile  power  of  the  muscular 
orgins,  examining  them  under  the  two-fold  relation  of  their  irritability, 
as  it  is  more  or  less  lively,  or  more  or  less  lasting,  looks  on  the  heart,  as 
the  one  in  which  these  two  conditions  are  found  in  the  highest  combina- 
tion. He  gives  the  second  place  to  the  intestines,  the  stomach,  the  blad- 
der, the  uterus,  and  the  diaphragm,  and,  after  these,  all  the  muscles  un- 
der the  command  of  the  will.  I  had  at  first  admitted,  with  every  other 
writer,  this  classification  of  the  contractile  parts;  but  more  than  a  hun- 
dred experiments  on  living  animals  have  satisfied  me,  that  the  intestines 
are  always  the  last  part  in  which  the  traces  of  life  may  be  discovered. 
Whatever  may  be  the  sort  of  death  by  which  they  are  destroyed,  peri- 
staltic motions,  undulations,  are  still  continued  in  this  canal,  while  the 
heart  has  already  ceased  to  beat,  and  the  rest  of  the  body  is  all  an  inani- 
mate mass.  Mr.  Jurine  had  already  observed  on  the  pulex  monoculus, 
that,  of  all  the  parts  of  the  body  of  this  little  white-blooded  animal,  the 
intestines  were  the  last  to  die. 

If  the  intestinal  tube  be  the  ultimum  moriens,  if  it  be  the  last  organ  in 
which  life  lingers  and  goes  out,  it  is  to  it  we  ought  to  direct,  in  prefer- 
ence, the  stimulants  that  are  capable  of  recalling  life  incase  of  asphyxia.  I 
think  that,  after  the  blowing  of  pure  air  into  the  lungs,  the  means  that 
ought  next  to  be  attended  to  is  the  injection  of  acrid  and  irritating  clys- 
ters, thrown  in  with  force.  The  large  intestines  are  connected  with  the 
diaphragm  by  a  close  sympathy,  as  is  proved  by  the  phenomena  of  fecal 
evacuation  ;  the  irritation  of  them  is  the  surest  means  of  accelerating;  it; 
and  this  irritation  is  the  easier,  as  the  alimentary  canal  is  the  last  part 

that  is  forsaken  bv  life. 

• 

§  V.    OF  LIFE4 

After  having  thus  laid  down,  between  organic  bodies  and  organized 
living  beings,  and  again  between  animal  and  vegetable  nature,  aHine  of 


*  An  error.  The  words  are,  *  UO-TT^  TOM  ftvfyta-iv  H  y*,  xru>  TVO-IV  faourtv  H  F  A2THP,  XM 
Tettu  xti  d-t£t/.Aivu  x*i  4u;ty>'  Which  is  thus  rendered  by  the  accurateFcissius,  «  ut  se  habet 
terra  in  arboribus  ita  in  animantibus  venter  al'.t  calet'acit  et  refrigerat.'  As  the  earth  does 
to  trees,  so  the  belly  supports,  heats,  and  cools  animals.  Though  the  book  on  the  'hu- 
mours,' is  received  as  genuine  by  Galen  and  Erotian,  it  must  be  remembered  that  com- 
mentators have  always  been  able  to  make  HIPPOCRATES  support  their  notions.  In  the 
sentence  quoted,  all  the  viscera  of*  the  abdomen  are  referred  to,  in  general  terms; 
x«,\«  is  the  word  used,  when  the  particular  organ,  the  stomach,  is  meant.  —  Godma-n. 

f  Opera  jnhiorat  3  vol.  4to.  ±  Sec  Appendix,  Note  A. 


17 

demarcation  that  cannot  be  mistaken,  let  us  endeavour  to  exalt  ourselves 
to  the  conception  of  Life  ;  and  for  accuracy  of  thought,  let  us,  in  some  sort, 
analyse  it,  by  studying  it  in  all  the  beings  of  nature  that  are  endowed  with 
it.  In  this  study,  of  which  I  may  be  allowed  to  state,  in  advance,  the  re- 
sults, we  shall  see  life  composed  at  first  of  a  small  number  of  phenomena, 
simple  as  the  apparatus  to  which  it  i»  given  in  charge;  but  soon  extend- 
ing itself  as  its  organs  or  instruments  are  multiplied,  and  as  the  whole  or- 
ganic machine  becomes  more  complex;  the  properties  which  character- 
ize it  and  bear  witness  of  its  presence,  at  first  obscure,  becoming  more 
and  more  manifest,  increasing  in  number  as  in  developement  and  energy ; 
the  field  of  existence  enlarging,  as  from  the  lower  beings  we  re-ascend  to 
man,  who,  of  all,  is  the  most  perfect;  and  observe,  that  by  this  term  of 
perfection,  it  is  simply  meant  that  the  living  beings  to  which  we  apply 
it,  possessed  of  more  means,  present  also  more  numerous  results  and 
multiply  the  acts  of  their  existence;  for  in  this  wonderful  order  of  the 
universe,  every  being  is  perfect  in  itself,  each  being  is  constructed  most 
favourably  for  the  purpose  it  is  to  fulfil;  and  all  is  equally  admirable,  in 
living  and  animated  nature,  from  the  lowest  vegetation  to  the  sublimity 
of  thought. 

What  does  this  plant  present  to  us'  that  springs  up,  and  grows,  and 
dies  every  year  ?  A  being  whose  existence  is  limited  to  the  phenomena  of 
nutrition  and  reproduction ;  a  machine  constructed  of  a  multitude  of  ves- 
sels, straight  or  winding,  capillary  tubes,  through  which  the  sap  is  filtra- 
ted and  other  juices  necessary  to  vegetation ;  these  vegetable  liquors  as- 
cend, generally, from  the  roots,  where  their  materials  are  taken  in,  to  the 
summit,  where  what  remains  from  nutrition  is  evaporated  by  the  leaves, 
and  what  the  plant  could  not  assimilate  to  itself  is  thrown  off  in  transuda- 
tion.  Two  properties  direct  the  action  of  this  small  number  of  functions: 
a  latent  and  faint  sensibility,  in  virtue  of  which,  each  vessel,  every  part 
of  the  plant,  is  affected  in  its  own  way  by  the  fluids  with  which  it  is  in 
contact;  a  contractility  as  little  apparent,  though  the  results  prove  irre- 
fragably  its  existence;  a  contractility,  in  virtue  of  which,  the  vessels, 
sensible  to  the  impression  of  liquids,  close  or  dilate  themselves,  to  effect 
their  transmission  and  elaboration.  The  organs  allotted  to  reproduction, 
animate,  for  a  moment,  this  exhibition  :  more  sensible,  more  irritable, 
they  are  visibly  in  action;  the  stamina,  or  male  organs,  bow  themselves, 
over  the  female  organ,  the  pistils,  shake  on  the  stigma  their  fertilizing 
dust,  then  straighten,  retire  from  it,  and  die  with  the  flower,  which  is 
succeeded  by  the  seed  or  fruit. 

This  plant,  divided  into  many  parts,  which  are  set  in  the  earth  with 
suitable  precautions,  is  reproduced  and  multiplied  by  slips,  which  proves 
that  these  parts  are  little  enough  dependent  on  each  other;  that  each  of 
them  contains  the  set  of  organs  necessary  to  life,  and  can  exist  alone. 
The  different  parts  of  a  plant  can  live  separately,  because  life,  its  simpler 
organs  and  properties  are  diffused  more  equably,  more  uniformly,  than  in 
animals  like  man,  and  its  phenomena  are  connected  in  a  less  strict  and 
absolute  dependence.  I  myself  have  witnessed  a  very  curious  fact,  which 
confirms  what  I  have  said*.  A  vine,  trained  against  the  eastern  wall  of 


*  Vegetable  life,  compared  in  its  means  and  in  its  results,  to  the  life  of  animals,  would 
throw  the  greatest  light  on  many  phenomena  which  it  is  still  difficult  for  us  to  conceive 
and  to  exp'ain.  The  treatment  of  disease  in  plants',  for  which  as  much  would  be  grained 


18 

a  forge,  shot  into  the  building  a  few  branches.  These  branches,  which 
entered  by  straight  enough  passages,  were  covered  with  leaves  in  the 
middle  of  the  hardest  winters ;  and  this  premature  but  partial  vegetation 
went  through  all  its  periods,  and  was  already  in  flower  when  the  part  re- 
mained without  was  beginning  to  bud  with  the  spring. 

If  we  pass  from  the  plant  to  th«  polypus,  which  forms  the  last  link  of 
the  animal  chain,  we  find  a  tube  of  soft  substance,  sensible  and  contractile 
in  all  its  parts,  a  life  and  organization  at  least  as  simple  as  that  of  the 
plant.  The  vessels  which  carry  the  liquids,  the  contractile  fibres,  the 
trachese,  which  give  access  to  the  atmospheric  air,  are  no  longer  distinct- 
ly to  be  traced  in  this  almost  homogeneous  substance.  There  is  no  or- 
gan especially  allotted  to  the  reproduction  of  the  kind.  Moisture  oozes 
from  the  internal  surface  of  the  tube,  softens  and  digests  the  aliments 
which  it  finds  there  ;  the  whole  mass  draws  in  nourishment  from  it ;  the 
tube  then  spontaneously  contracts,  and  casts  out  the  residue  of  digestion. 
The  mutual  independence  of  parts  is  absolute  and  perfect:  cut  the  crea- 
ture into  many  pieces,  it  is  reproduced  in  every  piece;  for  each  becomes 
a  new  polypus,  organized  and  living,  like  that  to  which  it  originally  be- 
longed. These gemmiparous  animals  enjoy,  in  a  higher  degree  than  plants, 
the  faculties  of  feeling  and  of  self-motion;  their  substance  dilates  and 
lengthens,  and  contracts,  according  to  the  impressions  they  receive.—- 
Nevertheless,  these  spontaneous  movements  do  not  suppose,  any  more 
than  those  of  the  mimosa,  the  existence  of  reflection  and  will ;  like  those 
of  a  muscle  detached  from  the  thigh  of  a  frog  and  exposed  to  galvanic 
excitation,  they  spring  from  an  impression  which  does  not  extend  beyond 
the  part  that  feels  it,  and  in  which  sensibility  and  contractility  are  blend- 
ed and  lost  in  each  other. 

From  this  first  degree  of  the  animal  scale,  let  us  now  ascend  to  worms. 
We  have  no  longer  a  mere  animated  pulp  shaped  into  an  alimentary  tube; 
parcels  of  contractile  or  muscular  fibres,  a  vessel  divided  by  several  con- 
strictions into  a  series  of  vesicles,  which  empty  themselves  one  into  ano- 
ther, by  a  movement  of  contraction  that  begins  from  the  head,  or  the  en- 
trance of  the  alimentary  canal,  and  proceeds  towards  the  tail,  which  an- 
swers to  the  anus,  a  vessel  from  which,  in  all  probability,  are  sent  out 
lateral  ramifications,t  a  spinal  mai  row  equally  knotted,  or  composed  of  a 


by  these  inquiries,  is  almost  entirely  surgical.  When,  to  make  vegetation  more  fruitful, 
the  gardener  prunes  a  luxuriant  branch  ;  when  the  peasants  of  the  Cervennes,  as  M. 
Chaptal  has  observe*!,  burn  the  inside  of  their  chesnut  trees  to  stop  the  progress  of  a 
destructive  caries ;  when  the  actual  cautery  is  applied  to  the  really  ichorous  and  foul  ul- 
cers of  many  trees,  &c.  it  is  to  the  organs  of  inward  life,  (or  that  which  carries  on  the 
process  of  assimilation)  the  only  life  of  vegetables,  that  surgery  is  applied;  while  on 
the  contrary,  in  man  and  animals,  it  is  to  the  derangement  of  the  external  organs  that 
the  remedy  is  directed.  I  shall  conclude  this  note  with  an  observation  on  the  wounds 
of  plants.  Like  those  of  the  human  body,  they  are  much  less  dangerous  when  their 
surface  is  smooth,  than  when  their  edges  are  hacked,  torn,  or  bruised.  Tre'es  felled 
with  the  saw  will  hardly  shoot  up  from  the  stool,  which  always  furnishes  a  better  growth 
when  an  axe  has  been*  employed.  The  saw  lacerates  the 'vegetable  texture,  and  its 
violent  and  distressing  action  on  the  fibres  extending  towards  the  roots,  affects,  more 
or  less,  the  organization.  The  uneven  surface  of  a  tree  felled  in  this  manner,  holds 
wet,  as  injurious  to  the  trunk,  which  it  rots,  as  a  too  great  quantity  of  pus,  which  bathes 
constantly  the  surface  of  a  wound,  checks  the  process  of  granulation,  and  resists  cica- 
trization.— Author's  J\'ote. 

-j-  This  class  of  animals  cannot  be  considered  to  possess  a  spinal  marrow.  The  series 
of  ganglions  which  they  exhibit,  is  merely  the  vertebral  ganglia  of  the  sympathetic 
nerve. —  Copland. 


19 

chain  of  ganglions*,  stigmas,  and  tracheae,  analogous  to  the  respiratory 
organs  of  plants,  and  in  some,  even  gills :  all  shows  clearly  an  organiza- 
tion further  advanced,  and  more  perfect :  sensibility  and  contractility  are 
more  distinct;  the  motions  are  no  longer  absolutely  automatic :  there  are 
some  which  seem  to  suppose  a  choice.  The  worm,  too,  may  be  divided 
into  many  pieces  ;  each  will  become  a  separate  and  perfect  worm;  a  head 
and  tail  growing  to  eachf;  but  this  division  has  its  term,  beyond  which 
there  is  no  longer  complete  regeneration.  It  cannot,  therefore,  be  push- 
ed so  far  as  in  the  polypi.  The  substance  of  the*  worm  being  formed  of 
elements  more  dissimilar,  it  may  be  that  too  smal]  a  portion  does  not  con- 
tain all  that  is  necessary  to  constitute  the  animal. 

The  crustaceous  tribes,  and  among  them  the  lobster,  discovers  a  more 
complex  apparatus  of  organization.  Here  you  will  find  distinct  muscles, 
an  external  articulated  skeleton,  of  which  the  separate  parts  are  move- 
able  upon  each  other,  distinct  nerves,  a  spinal  marrow  with  bulgings,  but, 
above  all,  a  brain  and  a  heart.  These  two  organs,  though  imperfect,  as- 
sign the  animal  to  an  order  much  above  that  of  worms.  The  first  be- 
comes the  seat  of  a  sort  of  intelligence ;  and  the  lobster  acts  evidently 
under  impulses  of  will,  when  attracted  by  a  smell,  it  pursues  a  distant 
prey,  or  when  it  flies  a  danger  discovered  to  it  by  its  eyes.  There  are 
viscera  accompanying  the  intestinal  tube,  which  give  out  to  it  liquids 
that  concur  in  alimentary  digestion.  Sensibility  and  contractility  pre- 
sent each  two  shades  :  in  fact,  the  parts  of  the  animal  are  obedient  to  the 
internal  stimuli,  feel  the  impression  of  fluids,  and  contract  to  impel  them ; 
on  the  other  hand,  by  its  nerves  and  locomotive  muscles,  the  lobster 
places  itself  in  connection  with  the  objects  that  surround  it.  The  phe- 
nomena of  life  are  linked  together  by  a  strict  necessity:  it  is  no  longer 
possible  to  separate  the  creature  into  two  parts,  of  which  each  may  con- 
tinue to  live;  there  are  but  few  parts  you  may  cut  off  without  injury, 
while  you  spare  the  central  foci  of  life.  So,  if  you  take  off  a  claw,  you 
observe  soon  a  little  granulation,  which  swells  and  is  developed,  and 
which,  soft  at  first,  is  soon  clothed  in  a  calcareous  covering  like  that 
"which  encloses  the  rest  of  its  body.  This  partial  regeneration  is  fre- 
quently to  be  seen. 

If  from  white-blooded  animals  we  go  on  to  the  red  and  cold-blooded, 
such  as  fishes  and  reptiles,  we  see  this  power  of  reproduction  becoming 
more  and  more  limited,  and  life  more  involved  in  organization.  In  fact, 
if  you  cut  off  a  part  of  the  body  of  a  fish,  the  tail  of  a  serpent,  or  the  foot 
of  a  frog,  the  separated  parts  are  either  not  supplied  at  all,  or  very  im- 
perfectly reproduced.  All  these  creatures  maintain,  with  the  medium  in 
•which  they  live,  relations  of  more  strict  dependence.  Gills  in  these,  lungs 
in  others,  are  added  to  a  heart,  nor  are  less  essential  to  life.  However, 
the  action  of  these  chief  organs  is  not  so  frequent,  nor  of  momentary  ne- 
cessity for  the  continuance  of  life.  The  serpent  passes  long  winters,  tor- 
pid with  cold,  in  holes  where  he  has  no  air,  without  breathing,  without  any 
motion  of  life,  and  in  all  appearance  dead.  These  creatures,  like  all  rep- 
tiles, are  able  to  breathe  only  at  long  intervals,  and  to  suspend,  for  a 
time,  the  admission  of  air,  without  risking  their  existence.  Here  the 


*  Appendix,  Note  B. 

f  This  may  be  observed  tn  several  of  the  intestinal  worms.    It  ought  to  be  kept  in 
recollection  during  our  endeavours  to  remove  them  from  the  body—  Copland, 


£0 

vital  powers  are  distinct  and  strong,  and  differ  from  those  of  the  more 
perfect  animals  and  of  man,  by  very  slight  shades:  thehean  and  the  ves- 
sels of  the  fish  feel  and  act  with  him,  without  his  consciousness.  Further, 
he  has  senses,  nerves,  and  a  brain,  from  which  he  has  intimation  of  what- 
ever can  affect  him;  muscles  and  hard  parts,  by  the  action  of  which  he 
moves,  and  changes  his  place,  adapting  himself  to  the  relations  that 
subsist  between  the  substances  around  him  and  his  own  peculiar  mode  of 
existence. 

We  are  come,  ai  last,  to  the  red  and  warm-blooded  animals,  at  the  head 
of  which  are  the  manuiiiferse  and  man.  They  are  entirely  alike,  save 
some  slight  differences  in  the  less  essential  organs.  There  is  none  that 
has  not  the  vertebral  column,  four  limbs,  a  brain  which  fills,  exactly,  the 
cavity  of  the  skull,  a  spinal  marrow,  nerves  of  two  sorts,  five  senses,  mus- 
cles, partly  obedient  to  the  will,  partly  independent  in  their  action;  add 
to  these  a  long  digestive  tube  coiled  upon  itself,  furnished  at  its  mouth 
with  agents  of  saliva  and  mastication  :  vessels  and  lymphatic  glands,  ar- 
teries and  veins,  a  heart  with  two  auricles,  and  two  ventricles,  tabular 
lungs,  which  must  act  incessantly  in  impregnating  the  blood,  that  passes 
through  them,  with  the  vital  part  of  the  atmosphere*,  which  if  it  fail,  life 
is  suspended  or  gone.  None  of  their  organs  live,  but  while  they  partake 
in  the  general  action  of  system,  and  while  they  are  under  the  influ- 
ence of  the  heart.  All  die,  irrecoverably,  when  they  are  parted  from  the 
body  of  the  animal,  and  are  in  no  way  replaced  ;  whatever  some  physio- 
logists may  have  said  on  pretended  regeneration  of  the  nerves  and  some 
other  pans. 

Every  thing  that  is  important  to  life,  is  to  be  found  in  these  animals; 
and  as  the  most  essential  organs  are  within,  and  concealed  in  deep  cavi- 
ties, a  celebrated  naturalist  was  correct  in  saying,  that  all  animals  are  es- 
sentially the  same,  and  that  their  differences  are  in  their  external  parts, 
and  chiefly  to  be  observed  in  their  coverings  and  in  their  extremities. 

The  human  body,  consisting  of  a  collection  of  liquids  and  solids,  con- 
tains of  the  former,  about  five-sixths  of  its  weight.  This  proportion  of 
the  liquids  to  the  solids,  may,  at  first  sight,  appear  to  you  beyond  the 
the  truth;  but  consider  the  excessive  decrease  of  size  of  a  dried  limb; 
the  glutseus  maxinnfs,  for  example,  becomes,  by  drying,  no  thicker  than 
a  sheet  of  paper.  The  liquids  which  constitute  the  greatest  weight  of 
the  body,  exist  before  the  solids;  for  the  embryo,  which  is  at  first  in  a 
gelatinous  state,  may  be  considered  as  fluid  ;  besides,  it  is  from  a  liquid 
that  all  the  organs  receive  their  nourishment  and  repair  their  wastes. 
The  solids,  formed  from  the  liquids,  return  to  their  former  state,  when, 
having  for  a  sufficient  length  of  time,  formed  a  part  of  the  animal,  they 
become  decomposed  by  the  nutritive  process.  Even  from  this  slight 
view  of  the  subject,  fluidity  is  seen  to  be  essential  to  living  matter,  since 
the  solids  are  uniformly  formed  from  the  fluids,  and  eventually  return  to 
their  former  state.  Solidity  is  then  only  a  transient  condition  and  an  ac- 
cidental state  of  organized  and  living  matter,  and  this  circumstance 
affords  to  the  humoral  pa,thologists  ample  opportunities  of  embarrassing 
their  opponents  with  many  objections  not  easily  answered.  Water  forms 
the  principal  part  and  the  principal  vehicle  of  all  the  animal  fluids,  it  con- 


*  Late  experiments  have  shown  that  a  different  process  takes  place  in  the  lungs.  See 
CHAPTER  or  RESPIRATION. 


tains  saline  substances  in  a  state  of  solution,  and  even  animal  matter  it- 
self is  found  in  it  fluid,  and  that  in  three  different  conditions,  under  the 
form  of  gelatine,  of  albumine,  or  fibrine.  The  first  of  these  substances, 
solidified,  forms  the  basis  of  ail  the  organs  of  a  white  colour,  to  which 
the  ancients  gave  the  name  of  spermatic  organs,  such  as  the  tendons,  the 
aponeurosis,  the  cellular  tissue,  and  the  membranes.  Albumine  exists  in 
abundance  in  almost  all  the  humours;  the  fibrine  of  the  blood  is  the  ce- 
ment which  is  employed  in  repairing  the  waste  of  a  system  of  organs, 
which,  in  point  of  bulk,  hold  the  first  rank  among  the  constituent  parts 
of  the  human  body — I  mean  the  muscular  system.  The  chemists  sus- 
pect, and  not  without  reason,  that  the  animal  matter  passes  successively 
through  the  different  states  of  gelatine,  albumine,  and  fibrine  $  that  these 
different  changes  depend  upoji  the  progressive  animalization  of  the  ani- 
mal matter,  which  is  at  first  gelatinous,  a  hydro-carbonous  oxycle,  con- 
taining no  azote,  and  acidifiable  by  fermentation,  becomes  more  closely 
combined  with  oxygen,  takes  up  azote,  so  as  to  become  albumen,  sub- 
ject to  putrefaction,  and  finally  fibrine,  by  a  super-addition  of  the  same 
principles. 

The  solid  parts  are  formed  into  different  systems,  to  each  of  which  is 
intrusted  the  exercise  of  a  function  of  a  certain  degree  of  importance. 
Limiting  the  term  organic  apparatus,  or  system,  to  a  combination  of 
parts  which  concur  in  the  same  uses,  we  reckon  ten,  viz.1 — the  digestive  ap- 
paratus, consisting  essentially  of  the  canal  which  extends  from  the  mouth 
to  the  anus;  the  absorbent,  or  lymphatic  system,  which  is  formed  of  the 
vessels  or  glands  of  that  name:  the  circulatory  system,  which  consists  of 
an  union  of  the  heart,  the  veins,  the  arteries,  and  the  capillary  vessels ;  the 
respiratory,  or  pulmonary  system ;  the  glandular^ or  secretory  system;  the 
sensitive  system,  including  the  organs  of  sense,  the  brain,  and  spinal  mar- 
row; the  muscular  system,  or  that  of  motion,  including  not  only  the  mus- 
cles, but  their  tendons  and  aponeuroses;  the  osseous  system,  including 
the  appendages  of  the  bones,  the  cartilages,  the  ligaments,  and  the  syno- 
vial  capsules,  the  vocal  system,  and  the  sexual,  or  generative  system,  dif- 
ferent in  the  two  sexes.  Each  of  these  organic  systems  contains  in  its 
structure  several  simple  tissues,  or  u  similar  parts,"  as  the  ancients  called 
them  : — these  tissues  in  man  may  be  enumerated  "es  follows,  cellular  tis- 
sue, nervous  tissue,  muscular  tissue,  besides  that  horny  substance  which  con- 
stitutes the  basis  of  the  epidermis,  the  nails  and  the  hair*. 


*  One  of  the  oldest  divisions  of  the  primary  textures  of  the  body,  and  one  winch  near- 
ly coincides  with  that  given  by  the  author,  acknowledges  three  tissues  only,  viz  •  the 
cellular,  nervous,  and  muscular.  This  arrangement  has  been  adopted  by  the  majority  of 
physiologists  since  the  time  of  Ilaller.  It  may  be  shown  tht  all  the  textures  and  organs 
of  the  body  result  either  from  the  various  distribution  of  these  primary  tissues ;  or  from 
the  cellular  only,  in  consequence  of  a  greater  condensation  of  its  substance,  or  approxi- 
mation of  the  molecules  of  matter  entering  into  its  constitution,  and  owing  to  a  deposi- 
tion of  earthy  substance  between  its  interstices,  sis  in  the  bones.  It  may/ however,  be 
a  matter  of  doubt  whether  the  muscular  texture  does  not  arise  from  the  union  of  the 
cellular  tissue  with  the  nervous  substance  ;  the  former  combining1  with  the  h'brillae  of  the 
organic  or  ganglial  nerves  to  form  the  muscular  fibre  generally,  whether  involuntary  or 
voluntary,  while  the  latter  class  of  muscles  derives  its  peculiar  characters  and  functions 
from  the  accession  of  the  fibrillae  of  voluntary  nerves  to  the  ganglial  and  cellular  tex- 
tures. If  this  position  be  allowed,  the  involuntary  fibres  will  appear  to  result  from  the 
combination  of  the  cellular  substance  with  the  ganglial  nerves  only,  the  voluntary  from 
the  union  of  the  cellular  with  both  the  ganglial  and  cerebral  matters  composing  the  ex- 
tremities of  their  ramifications ;  the  muscular  fibre  varying1  its  character  and  phenome- 


These  four  substances  may  be  considered  as  real  organic  elements, 
since  with  our  means  of  analysis,  we  never  can  succeed  in  converting  any 
of  these  substances  into  another.  The  cerebral  pulp  is  not  convertible 
into  a  horny  substance,  into  cellular  substance,  or  into  muscular  fibre, 
neither  can  any  one  of  these  tissues  ever  be  converted  into  cerebral  pulp. 
The  bones,  the  cartilages,  the  ligaments,  the  tendons,  the  aponeuroses, 
may,  by  long  maceration,  be  converted  into  cellular  substance.  Muscu- 
lar fibres  are  not  subject  to  that  alteration,  nor  is  the  nervous  or  cerebral 
pulp  :  the  horny  substance  also  resists  that  change.  Every  thing,  there- 
fore, leads  us  to  acknowledge  these  four  constituent  principles  in  our 
organs. 

The  primitive  or  simple  tissues,  variously  modified,  and  combined  in 
different  quantities  and  in  various  proportions,  constitute  the  substance 
of  our  organs.  Their  number  is  much  more  considerable,  according  to 
Bichat,  whose  happiest  conception  was  the  analysis  of  the  human  or- 
ganization. This  physiologist  reckoned  in  the  human  oeconomy,  no  few- 
er than  twenty-one  general  or  generating  tissues*.  But  it  is  evident, 
that  this  analysis  is  carried  too  far;  that  the  tissues  of  which  the  skin 
and  the  hair  are  formed,  are  exactly  of  the  same  nature,  are  analagous 
in  their  properties,  and  are  nourished  in  a  similar  manner ;  that  the  cel- 
lular tissne  is  the  common  basis  of  the  osseous,  cartilaginous,  mucous, 
serous,  synovial,  dermoid,  &c. 

It  must  be  confessed,  that  this  separate  consideration  of  each  organic 
tissue  has  furnished  him  with  new  ideas,  ingenious  analogies,  and  use- 
ful results,  and  that  his  "  Anatomic  Generate,"  in  which  those  research- 
es are  contained,  is  his  chief  title  to  glory.  That  glory  would  be  com- 
plete, if  in  that  book,  and  yet  more,  in  his  other  works,  he  had  done  his 


USE  according  as  more  or  less  of  either  kind  of  nervous  substance  enter  into  its  compo- 
sition. An  intimate  view  of  the  mode  of  distribution  which  characterizes  both  class  of 
nerves,  as  well  as  various  other  considerations,  support  this  opinion,  which  is  calculated 
to  form  the  basis  of  some  plausible  explanations  of  many  of  the  most  important  appear- 
ances and  functions  of  the  different  muscular  textures. 

*  The  following  classification  of  the  primary  and  compound  textures  nearly  coincides 
with  that  recommended  by  Dupuytren  and  Magendie  : 

fl.  Cellular. 


3.  Muscular 

r  Arterial. 

4.  Vascular.     .  .  .  .  . <Veinous. 

£  Lymphatic. 

5.  Osseous. 

f"  Fibrous. 

6.  Fibrous ,  .  .   <  Fibro-Cartiluginous. 

£  Dei-moid. 

7.  Erectile. 

8.  Mucous. 

9.  Serous. 
10-  Synovial. 
11.  Glandular. 

^.12.  Epklermous.  or  Corneous. —  Copland, 


23 

predecessors,  as  well  as  his  contemporaries,  the  justice  they  had  a  right 
to  expect  from  him. 

The  simple,  or  elementary  fibre,  about  which  so  much  has  been  writ- 
ten, may  be  considered  as  the  philosopher's  stone  of  physiologists*.  In 
vain  has  Haller  himself  in  his  pursuit  of  his  chimera,  told  us,  that  the 
elementary  fibre  is  to  the  physiologist  what  the  line  is  to  the  geometer, 
and,  that  as  all  figures  are  formed  from  the  latter,  so  are  all  the  tissues 
formed  from  this  fibre  :  Fibra  enim  fihysiologo  id  est  quod  linea  geametrae, 
ex  qua  nempe  jigurse  omnes  oriuntur.  The  mathematical  line  is  imaginary, 
and  a  mere  abstraction  of  the  mind,  while  the  elementary  fibre  is  allowed 
a  material  or  physical  existence.  Nothing,  therefore,  can  make  us  ad- 
mit the  existence  of  a  simple,  elementary,  or  primitive  fibre,  since  our 
senses  show  us  in  the  human  organization,  four  very  distinct  materials. 

Among  the  organs,  whether  single  or  combined  in  systems,  which  en- 
ter into  the  human  organization,  there  are  some  whose  action  is  so  essen- 
tial to  life,  that  with  the  cessation  of  that  action,  life  at  once  becomes 
extinct.  These  primary  systems,  whose  action  regulates  that  of  all  se- 
secondary  systems,  are  as  numerous  in  man  as  in  the  other  warm-blooded 
animals.  None  of  them  can  act  unless  the  heart  sends  into  the  brain  a 
certain  quantity  of  blood,  vivified  by  the  contact  of  atmospherical  air  in 
the  pulmonary  tissue.  Every  serious  wound  of  the  brain  or  heart,  every 
lasting  interruption  to  the  access  of  blood  into  the  former  of  these  organs, 
is  invariably  attended  with  death.  The  oxydation  of  the  blood,  and  its 
distribution  into  all  the  organs,  is  consequently  the  principal  phenome- 
non on  which  the  life  of  man  and  of  the  most  perfect  beings  depend. 

§VI.    OF   THE   VITAL   PROPERTIES;   SENSIBILITY   AND 
CONTRACTILITY!. 

By  sensibility  is  meant  that  faculty  of  living  organs,  which  renders  them 
capable  of  receiving  from  the  contact  of  other  bodies,  an  impression 
stronger,  or  fainter,  that  alters  the  order  of  their  motions,  increases  or 
diminishes  their  activity,  suspends,  or  directs  them.  Contractility  is  that 
other  property  by  which  parts  excited,  that  is,  in  which  sensibility  has 
been  called  into  action,  contract  or  dilate,  in  a  word,  act,  and  execute 
motions.  In  the  same  manner,  as  we  have  not  always  a  consciousness  of 
the  impressions  received  by  our  organs,  and  as,  for  example,  no  sensa- 
tion informs  us  of  the  stimulating  impression  by  which  the  blood  calls 
the  heart  into  action,  so  it  is  by  reflexion  only,  that  we  are  induced  to 
admit  the  existence  of  certain  motions;  of  those,  for  instance,  by  which 
the  humours,  when  they  have  reached  the  smallest  vessels,  become  in- 


*  Almost  every  physiologist  who  has  written  on  Animal  Organization  has  proposed  a 
new  arrangement  of  the  primary  textures.  We  will  only  take  notice  of  the  two  follow- 
ing :  —  WALTIIER  considered  the  different  organs  and  compound  textures  to  result  from 
the  cellular  or  membranous,  the  vascular  orjibroiis,  and  from  the  nervous.  J.  F.  MECKEI. 
founds  his  classification  of  organic  substances  on  microscopic  researches.  He  is  of  opi- 
nion that  the  solids  and  fluids  of  the  human  body  can  be  reduced  to  t~co  elementary  sub- 
stances, the  one  formed  by  globules,  the  other  by  a  coagulable  matter,  which,  either 
alone  or  united  to  the  former,  constitutes  the  living  fluids,  if  it  be  in  the  liquid  state,  and 
-ivc 


to  the  solid  tissues,  when  it  assumes  the  concrete  form.     See  APPENDIX, 
Note  C,  for  a  more  detailed  account  of  the  opinion  of  this  eminent  Anatomist.  -Copland 
f  See  APPENDIX,  Note  D. 


24 

corporalecl  into  the  tissue  of  our  organs*.  These  motions,  to  make 
use  of  an  ingenious  comparison,  resemble  those  of  the  hour-hand,  com- 
pared with  the  second-hand  of  a  watch.  The  hour-hand  appears  motion- 
less, and  yet  in  twelve  hours  it  describes  the  whole  circumference  of  the 
dial-plate,  round  which  the  other  hand  moves  in  one  minute,  with  a  mo- 
tion that  is  visible. 

In  considering  life  through  the  great  series  of  beings  that  possess  it, 
we  have  seen  that  those  in  which  it  is  most  limited,  or  rather  in  which  it 
consists  of  the  least  number  of  actions,  and  phenomena,  vegetables,  for 
instance,  and  animals  like  the  polypus,  which  have  no  brain,  no  distinct 
nervous  system,  are  at  once  endowed  with  sensibility  and  contractility  in 
all  their  parts.  All  living  beings,  all  the  organs  which  enter  into  their 
composition,  are  impregnated,  if  we  may  be  allowed  the  expression,  with 
these  two  faculties,  necessarily  co-existing,  and  which  show  themselves 
by  internal  and  nutritive  motions,  obscure,  indeed,  and  to  be  distinguish- 
ed only  by  their  effects.  These  two  faculties  appear  to  exist  in  the  de- 
gree absolutely  required  for  enabling  the  fluids  that  pervade  all  the  parts 
of  a  living  body,  to  induce  the  action  by  which  these  parts  are  to  assimi- 
late such  fluids.  It  is  clear,  that  the  two  properties  of  feeling  and  of 
motion  are  indispensable  to  all  parts  of  the  body.  They  are  properties 
universally  diffused  through  organized  and  living  matter,  but  they  exist 
withous  possessing  any  peculiar  organ  or  instrument  of  actionf.  Were  it 
not  for  these  two  faculties,  how  would  the  different  parts  act  on  the 
blood,  or  on  the  fluid  which  supplies  its  place,  so  as  to  obtain  from  it 
the  materials  subservient  to  nutrition  and  the  different  secretions  ?  These 
faculties  are  therefore  given  to  every  thing  that  has  life — to  animals, 
to  vegetables;  to  man  in  his  waking  hours,  or  in  his  most  profound 
sleep,  to  the  foetus,  to  the  child  that  is  born,  to  the  organs  of  the  assimi- 
lating functions,  and  to  those  which  connect  us  with  surrounding  beings. 
Both  these  faculties,  obscure,  and  inseparable,  preside  over  the  circula- 
tion of  the  blood,  of  the  fluids,  and,  in  short,  over  all  the  phenomena  of 
nutrition. 

Though  this  kind  of  sensibility  is  always  latent  or  concealed,  it  is  other- 
wise with  regard  to  contractility,  which  may  be  sensible  or  otherwise. 
The  bone,  which  takes  up  the  phosphate  of  lime,  to  which  it  owes  its 
solidity,  exerts  that  action  without  our  being  aware  of  its  taking  place, 
except  by  its  effect :  but  the  heart  which  feels  the  presence  of  the  blood, 
without  any  consciousness,  on  our  part,  of  such  sensation,  exerts  motions 
that  are  easily  perceptible,  but  over  which  we  have  no  controul,  either  to 
suspend  or  accelerate  them. 

Vital  properties  in  so  weak  a  degree,  would  not  have  been  sufficient  to 


*  If  the  suggestions  offered,  in  the  Note  at  p.  12,  respecting  the  constitution  of  the 
different  kinds  of  muscular  fibres,  were  adopted,  the  explanation  of  the  properties,  sen- 
sibility and  contractility,  and  the  relations  which  they  hold  with  the  circle  of  vital  func- 
tions, wov-lu  be  more  apparei.f  and  better  understood. —  Copland, 

•f-  Tiiis  is  an  impossibility.  If  there  be  feeling  and  motion,  a  material  capable  affecting, 
aud  a  power  capable  of  moving  are  presupposed.  If  the  feeling1  and  motion  belong-  to 
the  fluid  independent  of  organization,  the  results  are  merely  plays  of  chemical  affini- 
ties, and  the  changes  taking'  place,  mere  superpositions.  But  the  polypus  is  confess- 
edly organized  and  digests,  so  that  although  we  do  cut  it  in  pieces,  the  parts  or  whole 
reproduced,  are  formed  by  the  action  of  the  remaining1  organization  on  the  fluids,  and 
not  by  the  fluids  themselves.  The  feeling- and  motion  are  attributable  solely  to  impres- 
sions made  on  a  nervous  and  muscular  system,  however  singular  in  its  kind. — Godman. 


25 

the  existence  of  man  and  of  the  animals  which  resemble  him,  obliged  to 
keep  up  multifarious  intercourse  with  every  thing  that  surrounds  them  ; 
thus  they  enjoy  a  very  superior  kind  of  sensibility,  by  means  of  which  the 
irnpresssons  which  affect  some  of  their  organs  are  perceived,  judged,  and 
compared.  This  mode  of  sensibility  might  be  more  properly  called  per- 
ceptibility, or  the  faculty  of  accounting  to  one's  self  for  the  emotions  which 
are  experienced.  It  requires  a  centre  to  which  t  e  impressions  may  be 
referred,  and  therefore  it  exists  only  in  the  animals  which,  like  man,  have 
a  brain  or  some  organ  in  its  stead  ;  so  that  the  zoophytes  and  vegetables, 
wanting  that  organ,  are  equally  destitute  of  this  faculty.  The  polypi, 
and  some  plants,  as  the  sensitive,  perform  nevertheless  certain  sponta- 
neous motions,  which  seem  to  indicate  the  existence  of  volition,  and  con- 
sequently of  perceptibility.  But  these  motions  are  the  result  of  an  im- 
pression, which  does  not  extend  beyond  the  part  in  which  it  is  experi- 
enced, and  in  which  sensibility  and  contractility  are  blended. 

The  almost  latent  sensibility  of  certain  parts  of  the  body,  cannot  be  ab- 
solutely compared  to  that  of  vegetable;  since  those  organs  whose  sensi- 
bility is  so  imperfect,  manifest  in  disease  a  percipient  sensibility,  which 
shows  itself  by  acute  pain,  and  it  is  even  sufficient  to  change  the  stimulus 
to  which  they  are  accustomed,  to  determine  the  occurrence  of  that  phe- 
nomena. Thus  the  stomach,  on  the  parietes  of  which,  the  food  does  not 
in  health  produce  any  perceptible  impression,  becomes  the  seat  of  very 
distinct  sensation  and  of  dreadful  pain,  when  a  small  quantity  of  poison- 
ous matter  is  introduced  into  it.  In  like  manner,  we  are  not  conscious  of 
the  impressions  excited  in  the  parietes  of  the  bladder  or  rectum,  by  the 
collection  of  urme^or  foecal  substances,  except  when  their  contents  have 
become  sufficiently  irritating  by  their  presence,  to  excite  in  a  certain  de- 
gree, those  irritable  and  sentient  cavities,  and  to  transform  their  obscure, 
into  a  very  distinct  sensibility.  Is  there  not  reason  to  suspect,  that  our 
unconsciousness,  in  health,  of  the  impressions  made  on  our  organs  by  the 
fluids  which  they  contain,  depends  on  our  being  accustomed  to  the  sensa- 
tions which  they  incessantly  excite?  so  that  there  remains  but  a  confused 
perception,  which  in  time  disappears,  and  may  we  not,  under  that  point 
of  view,  compare  all  these  organs  to  those  of  sight,  hearing,  smelling, 
tasting,  and  touching,  that  are  no  longer  irritable  by  stimulants,  to  which 
they  have  long  been  habituated  ? 

Two  systems  of  organs,  very  different  in  their  uses  and  in  their  quali- 
ties, enter  into  the  composition  of  the  human  body;  they  are  as  two  liv- 
ing and  united  machines,  the  one,  formed  by  the  organs  of  sense,  the 
nerves,  the  brain,  the  muscles,  and  the  bones,  serves  to  maintain  its  con- 
nexion with  external  objects:  the  other,  destined  to  internal  life,  con- 
sists in  the  digestive  tube,  and  the  organs  of  absorption,  circulation, 
respiration,  and  secretion.  The  organs  of  generation  in  the  two  sexes 
form  a  separate  class,  which,  as  far  as  relates  to  the  vital  properties,  par- 
takes of  the  nature  of  the  other  two. 

By  the  organs  of  sense,  and  the  nerves  which  form  a  communication 
between  these  organs  and  the  brain,  we  are  enabled  to  perceive  or  to  feel 
the  impressions  made  onus  by  external  objects  :  the  brain,  the  true  seat 
of  that  relative  sensibility,  which  might  very  justly  be  termed  perceptibility 
or  the  perceptive  power,  (Pott)  when  excited  by  these  impressions,  is  able 
to  irradiate  into  the  muscles  the  principle  of  motion,  and  to  induce  the 
exertion  of  their  contractility.  This  property,  which  is  under  the  direc- 
tion of  the  will,  manifests  itself  by  the  sudden  shortening  of  a  muscle, 

'D 


« 


which  swells,  hardens,  and  determines  the  motion  of  those  parts  of  the 
skeleton  to  which  it  is  attached.  The  nerves  and  the  brain  are  essenti- 
ally the  organs  of  these  two  properties,  a  division  of  the  former  is  attend- 
ee} with  a  loss  of  sentiment  and  voluntary  motion  in  the  parts  to  which 
they  are  distributed.  The  other  kind  of  sensibility  is,  on  the  contrary, 
quite  independent  of  the  presence  of  nerves;  it  exists  in  all  organs, 
although  all  do  not  receive  nervous,filaments.  It  might  even  be  asserted, 
that  the  cerebral  nerves  are  not  at  all  essential  to  the  life  of  nutrition ;  the 
bones,  the  arteries,  the  cartilages,  and  several  other  tissues,  in  which  no 
nerves  are  seen  to  enter,  are  nourished  equally  well  with  the  organs  in 
which  they  exist  in  considerable  number ;  the  muscles  themselves  will 
carry  on  their  own  internal  osconomy,  notwithstanding  the  division  of 
their  nerves ;  only,  deprived  of  those  means  of  communication  with  the 
brain,  they  can  no  longer  receive  from  it  the  principle  of  voluntary  con- 
traction; instead  of  that  sudden,  energetic,  and  lasting  shortening,  which 
the  will  determines  in  them,  they  become  merely  capable  of  those  quiver- 
ings called  palpitations. 

The  anatomist  who  studies  the  nerves  with  a  view  to  ascertain  their 
termination,  finds  them  all  arising  from  the  brain  and  spinal  marrow,  and 
proceeding  by  a  longer  or  shorter  course,  to  the  organs  of  motion  or  of 
sensation;  let  him  take  his  scalpel  and  dissect  one  of  our  limbs,  the  thigh, 
for  instance,  he  will  see  the  cords  parting  into  numerous  threads,  most  of 
which  disappear  in  the  thickness  of  the  muscles,  whilst  others,  after 
creeping  for  a  time  about  the  cellular  tissue,  which  joins  the  skin  to  the 
apon  eurosis,  end  on  the  inward  surface  of  the  skin,  of  which  they  com- 
pose the  texture,  and  expand  into  sentient  papillae  on  its  furface.  The 
bones,  the  cartilages,  the  ligaments,  the  arteries,  and  the  veins,  all  those 
parts  whose  action  is  not  under  the  controul  of  the  will,  are  without 
them*.  Nevertheless,  all  those  parts,  which,  in  their  natural  state,  send 
no  perceptible  impressions  to  the  brain,  which,  when  once  insulated,  may 
be  tied  and  cut,  without  any  sign  of  pain  from  the  animal,  and  whose  ac- 
tion the  will  does  not  controul.  are  yet  endued  with  a  sensibility  and  a 
contractility,  which  enable  them,  after  their  own  manner,  to  feel  and  to 
'  act,  to  recognize  in  the  fluids  that  moisten  them,  what  is  suited  to  their 
nourishment,  and  to  separate  that  recrementitious  part  which  has  suita- 
bly affected  their  particular  mode  of  sensibility!. 

In  confining  our  attention  then,  to  the  consideration  of  a  single  limb, 
we  may  easily  satisfy  ourselves  of  the  existence  of  two  modes  of  feeling, 

*  Comparatively  speaking ;  the  nerves  may  be  traced  into  bones,  accompanying- 
their  arteries  and  veins,  and  we  should  with  greater  propriety  declare  that  toe  cannot 
see  them  in  the  coats  of  arteries  and  veins,  than  that  they  do  not  exi.st  We  are  unable 
to  conceive  how  such  vessels  can  be  organs  of  secretion,  assimilation  or  absorption 
without  a  nervous  system  of  their  own  ;  which  we  believe  has  its  peculiarities  and  mo- 
difications to  suit  the  purposes  for  which  it  is  designed. — Godman. 

•f-  All  these  parts  may  be  considered  to  possess  ganglial  nerves  ;  for  as  these  nerves 
may  be  demonstrated  on  the  more  considerable  trunks  of  arteries,  even  in  the  extremi- 
ties, they  may  be  supposed  to  accompany  these  vessels  to  their  most  minute  ramifica- 
tions and  terminations,  and  to  bestow  on  them  the  manifestations  which  these  parts  of 
the  vascular  system  evince.  Such,  then,  being  the  constitution  and  connexion  of  the 
arterial  and  capillary  vessels,  no  texture  which  possess  these  vessels  can  be  considered 
to  be  destitute  of  this  class  of  nerves.  Those  nerves  that  belong  to  the  other  class,  or 
the  cerebral,  may  be  inferred  to  exist,  in  an  organ,  more  or  less  abundantly,  or  to  be 
entirely  absent  from  it,  according  to  the  nature  of  the  phenomena  which  that  organ 
presents.  See  CHAPTERS  OK  THE  CIRCULATION,  SENSATION  AND  MOTION. 


*as  of  two  sorts  of  motion  5  a  sensibility  in  virtue  of  which,  certain  parts 
can  send  up  to  the  brain,  the  impressions  they  receive,  to  be  there  objects 
of  consciousness ;  and  another  sensibility  belonging  to  all  organs  without 
exception,  and  all  that  some  of  them  possess,  which  is  sufficient  for  the 
exercise  of  the  functions  ©f  nutrition,  and  by  means  of  which  they  are 
evolved,  and  kept  up  in  their  natural  state ;  two  kinds  of  contractility, 
appropriated  to  the  two  different  kinds  of  sensibility: — The  one,  in  vir- 
tue of  which  the  muscles  obedient  to  the  will,  exercise  the  contractions 
which  it  determines;  the  other,  independent  of  the  will,  manifests  itself 
by  actions,  of  which  we  have  no  intimation,  any  more  than  of  the  im- 
pressions by  which  they  are  determined. 

The  distinction  being  fairly  laid  down  between  sensibility  and  contrac- 
tility, it  is  easy  to  understand  the  origin  of  the  endless  disputes  of  Haller 
and  his  followers,  about  the  parts  of  the  body,  in  man  and  animals,  which 
are  endowed  with  sensibility  andt  irritability.  All  the  organs  to  which' 
that  learned  physiologist  has  denied  these  properties,  as  bones,  tendons, 
membranes,  cartilages,  and  cellular  membrane,  &c.  possess  only  that 
latent  sensibility,  and  that  obscure  contractility,  common  to  all  living 
beings,  and  without  which,  it  is  impossible  to  conceive  life  to  exist.  In 
a  state  of  health,  they  are  utterly  incapable  of  transmitting  to  the  brain 
perceptible  impressions,  and  of  receiving  from  it  the  principle  of  mani- 
fest and  sensible  motion.  It  has  likewise  been  a  matter  of  much  dispute, 
whether  sensibility  and  contractility  are  qualities,  of  nerves;  if  these 
parts  are  their  only  instruments,  and  if  their  destruction  is  attended  with 
a  loss  of  these  two  vital  properties,  in  the  parts  to  which  they  are  trans- 
mitted. We  may  answer  in  the  affirmative,  as  far  as  relates  to  the  sensi- 
bility of  perception,  and  the  voluntary  motion  which  is  entirely  subser- 
vient to  it,  but  that  the  existence  of  nerves  is  not  at  all  necessary  to  the 
exercise  of  the  sensibility  and  contractility  which  are  indispensable  to 
the  assimilation  of  nutrition. 

No  part'of  the  living  body  is  absolutely  insensible,  but  that  sensibility 
of  every  organ  is  so  modified,  that  it  is  not  affected  by  the  same  stimuli. 
Thus,  the  eye  is  insensible  to  sound,  and  the  ear  to  light.  A  solution  of 
tartar  emetic,  causes  no  disagreeable  impression  to  the  conjunctiva; 
taken  into  the  stomach,  it  excites  convulsive  motions,  while  an  acid  from 
which  the  stomach  does  not  suffer,  proves  a  cause  of  irritation  to  the  con- 
junctiva, and  brings  on  a  violent  inflamation  of  the  eye.  In  the  same 
manner,  purgatives  pass  along  the  stomach,  without  producing  any  ef- 
fect on  the  viscus,  but  they  stimulate  the  alimentary  canal.  Cantharides 
have  a  specific  action  on  the  bladder;  and  mercury  on  the  salivary 
glands.  Eacn  part  feels,  lives,  moves,  after  its  own  way  5  in  each  the 
vital  properties  appear  under  such  shades  and  modifications,  that  they 
may  be  looked  upon  as  so  many  separate  members  of  the  same  family, 
concurring  in  one  endeavour,  working  for  a  common  end,  consentientia 
omnia.  (Hipp.) 

The  faculty  of  assigning  a  cause  to  the  sensation,  and  that  of  moving 
by  volition,  which  man  possesses  in  common  with  all  animals  formed 
with  a  distinct  nervous  centre,  are  essentially  bound  together.  For  sup- 
pose a  living  being,  furnished  with  locomotive  organs,  but  without  sen- 
sation, placed  in  the  midst  of  bodies,  that  every  moment  endanger  its 
existence,  without  any  means  of  distinguishing  them,  it  will  hasten  its 
own  destruction.  If  perceptibility  could,  on  the  other  hand,  exist  inde- 
pendently of  motion,  how  dreadful  would  be  the  fate  of  such  sentient  be- 


28     . 

being,  similar  to  the  fabulous  Hamadryads,  who,  immoveably  fixed  in  the 
trees  of  our  forests,  received,  without  any  power  to  shun  them,  all  the 
blows  inflicted  on  their  rustic  abode.  Dreams  place  us  sometimes  in 
situations  which  give  us  a  just  idea  of  their  condition.  A  certain  dan- 
ger threatens  our  existence  ;  an  enormous  rock  seems  to  detach  itself,  to 
roll  and  precipitate  itself  on  our  frail  machine ;  a  frightful  monster 
seems  to  pursue  us,  and  opens  a  yawning  mouth  to  ingulf  us.  We  strug- 
gle to  escape  this  imaginary  danger,  to  avoid  or  to  repel  it,  but  an  irre- 
sistible and  unknown  power,  a  mighty  hand  paralyses  our  efforts,  and 
keeps  us  rooted  to  the  spot;  it  is  a  situation  of  horror  and  despair,  and 
we  awaken  overwhelmed  with  the  uneasiness  which  we  have  suffered. 

As  there  is  no  part  that  does  not  feel,  in  a  manner  peculiar  to  itself,  so 
there  is  no  one  that  does  not  act,  move,  or  contract,  in  a  manner  peculiar 
to  itself;  and  the  parts  which  have  been  found  without  a  power  of  mo- 
tion analagous  to  muscular  contractility,  have  remained  in  thaf  state  of 
immobility,  only  for  want  of  a  stimulus  fitted  to  their  peculiar  nature. 
Some  physiologists  say  they  have  excited  a  distinct  quivering,  in  the  me- 
sentery of  a  frog  and  of  a  cat,  by  touching  them  after  they  had  been  pre- 
viously moistened  with  alcohol,  or  muriatic  acid, 

In  the  operation  for  sarcocle*,  I  have  often  perceived  that  while  with 
my  left  hand  I  supported  the  tumour,  and  with  a  scalpel  in  the  right,  di- 
vided the  spermatic  chord,  the  tunica  vaginalis  showed  oscillatory  con- 
tractions. It  visibly  contracts  in  the  operation  for  hydrocele.  The  in- 
jection of  an  irritating  fluid  determines  evident  motions  in  the  tunica 
vaginalis.  The  osseous  tissue,  notwithstanding  the  phosphate  of  lime 
with  which  it  is  incrusted,  is  susceptible  of  a  contraction,  whose  effects, 
though  slow,  are  nevertheless  undeniable.  After  teeth  have  been  shed 
or  extracted,  the  edges  of  the  alveolar  process  become  thinned  and 
the  alveolar  cavities  disappear.  These  facts  appear  to  me  to  prove, 
still  better  than  all  the  experiments  performed  on  living  animals, 
(experiments  of  which,  by  the  way,  the  results  ought  nbt  too  con- 
fidently to  be  applied  to  the  oeconomy  of  man)  what  one  should  think 
of  the  assertions  of  Haller  and  his  followers,  on  the  insensibility  and 
inirritability  of  the  serous  membranes,  and  of  the  organs  of  a  structure 
analagous  to  their's. 

We  will,  at  present,  say  nothing  of  the  porosity,  of  the  divisibility,  of 
the  elasticity,  and  other  properties  which  are  common  to  living  bodies  and 
inanimate  substances.  These  properties  are  never  possessed  in  their 
whole  extent,  and  in  all  their  purity,  if  that  expression  may  be  allowed. 
Their  results  are  always  influenced  by  the  vital  power,  which  constantly 
modifies  the  effects  which  seem  to  depend  most  immediately  upon  a  phy- 
sical, chemical,  or  mechanical  cause,  or  upon  any  other  agent  whatsoever. 

*  The  contraction  of  the  membrane,  formed  by  the  expansion  of  the  cremaster  mus- 
cle, has  doubtless  assisted  in  rendering  more  dittinctthe  appearance  in  question.  This 
effect  must  be  particularly  distinct  at  the  moment  of  dividing-  the  spermatic  chord. 
The  contraction  of  the  same  muscles  corrugate  the  skin  of  the  scrotum  when  tiiis  part 
is  exposed  to  cold,  and  draw  up  the  testicles  towards  the  inguinal  ringf.  The  contrac- 
tility of  the  skin  of  the  scrotum,  has  but  little  influence  in  procuring-  this  effect.— Jt. 

f  This  assertion  may  lead  to  error ;  the  testicles  are  raised  by  the  cremasters,  and 
this  is,  or  may  be  made  a  voluntary  action ;  but  the  corrugation  of  the  scrotum  is  inde- 
pendent of  the  will,  and  is  produced  by  a  contraction  directly  the  reverse  of  that  effect- 
ed by  the  cremasters,  i.  e.  laterally,  while  that  of  the  cremasters  is  perpendicular. — 

Godman. 


29 

Not  so  with  the  truly  vital  extensibility •,  which  is  so  manifest  in  certain 
organs,  as  the  penis  and  the  clitoris.  When  excited,  they  become  tur- 
gid and  dilated  by  the  afflux  of  blood,  but  that  effect  does  not  depend 
on  a  peculiar  property,  distinct  from  sensibility  and  contractility.  These 
parts  dilate,  their  tissue  stretches  under  the  action  of  these  two  proper- 
ties, which  would  occasion  the  same  phenomenon  in  all  other  parts,  if 
their  structure  were  similar. 

The  same  applies  to  caloricity,  or  that  power  inherent  in  all  living  be- 
ings, of  maintaining  the  same  degree  of  heat,  in  varying  temperatures*. 
In  consequence  of  which  property,  the  human  body  preserves  its  tempera- 
ture, of  from  thirty  to  forty  degrees  (Reaumur's  scale)  under  the  frozen 
climate  of  the  polar  regions,  as  well  as  in  the  burning  atmosphere  of 
the  torrid  zone.  It  is  by  the  exercise  of  sensibility  and  of  contrac- 
tility, that  is,  by  the  exercise  of  the  functions  over  which  these  vital 
powers  preside,  that  the  body  resists  the  equally  destructive  influence  of 
excessive  heat  and  cold. 

If  we  were  to  admit  caloricity  as  one  of  the  vital  properties,  because, 
according  to  Professor  Chaussier  that  power  of  preserving  a  uniform 
warmth  is  a  very  remarkable  phenomenon;  we  might  be  led  to  suppose, 
a  distinct  cause  or  a  peculiar  property  to  operate  iu  producing  other  phe- 
nomena of  no  less  importance. 

Barthez  and  Professor  Dumas  have  fallen  into  the  same  error,  the  for- 
mer, in  wishing  to  establish  the  existence  of  a  power  of  permanent  siutua- 
tion  in  the  molecules  of  muscular  fibres;  the  latter,  in  adding  to  sensibili- 
lity  and  contractility  a  third  property,  which  he  terms  the  power  of 
vital  resistance.  Living  muscles  are  torn  with  much  more  difficulty  than 
when  dead,  because  the  contractility  which  these  organs  possess  m  the 
highest  degree,  is  incessantly  tending  to  preserve  the  contact  of  the  mo- 
lecules, the  series  of  which  forms  the  muscular  fibre,  and  even  to  draw 
them  into  closer  connexion.  This  fact,  which  is  brought  forward  as  a 
proof  of  the  existence  of  a  peculiar  power,  is  easily  explained,  on  the 
principle  of  contractility. 

Organized  and  living  bodies  resist  putrefaction,  from  the  very  circum- 
stance of  their  being  endowed  with  life.  The  continual  motion  of  the 
fluids,  the  re-action  of  the  solids  on  the  fluids,  the  successive  and  conti- 
nual renovation  of  the  latter,  by  the  reception  of  new  chyle,  their  constant 
purification  by  means  of  the  secretions,  through  which  the  products  ani- 
malized  in  excess  are  parted  with,  such  are  the  causes  which  prevent  the 
putrefactive  action  from  taking  place  in  bodies  endowed  with  life,  not- 
withstanding the  multiplicity  and  the  volatility  of  their  elements.  Their 
preservation  is  therefore  a  secondary  effect,  and  depending  on  the  exer- 
cise of  the  functions  regulated  by  sensibility  and  contractility.  Nature 
is  distinguished  for  deriving  a  multitude  of  effects  from  a  very  small 
number  of  causes,  it  therefore  shows  a  very  imperfect  acquaintance  with 
her  laws  to  assign  a  separate  cause  to  each  fact. 

The  separation  of  the  chyle,  which  takes  place  in  the  duodenum,  from 
the  admixture  of  the  bile  with  the  alimentary  substance,  the  vivification 
of  the  blood  by  respiration,  the  secretion  of  the  fluids  in  tha  conglobate 
glands,  nutrition  in  the  organs,  are  so  many  acts  of  the  living  oeconomy, 


*  See  the  notes  on  the  subject  of  animal  heat  contained  in  the  CHAPTER  ON  RES- 
PIRATION. 


3D 

to  which  one  might  feel  disposed  to  assign  distinct  causes ;  but  these 
chemico-vital  processes,  are  so  subordinate  to  sensibility  and  contractili- 
ty, that  they  are  met  with  only  in  organs  endowed  with  these  two  proper- 
ties, and  they  take  place,  in  a  degree  more  or  less  perfect,  according  to 
the  condition  of  these  properties  in  the  organs  in  which  they  occur. 

We  have  stated  that  there  exists  two  great  modifications  of  sensibility 
and  contractility  ;  that  sensibility  is  divided  into  percipient  sensibility  and 
latent  sensibility  ^  that  contractility  is  at  times  voluntary,  at  others  involun- 
tary, and  that  the  latter  may  be  perceivable  or  insensible. 

" Perceiving,     (cerebral,  nervous,  animal,  sensib ility, per- 
ceptibility.} 
With  consciousness  of  impressions  or  perceptibility ; 

requires  a  peculiar  apparatus. 
SENSIBILITY.          <  Latent,    (nutritive, organic  sensibility.) 

Without  consciousness  of  impressions;  or,  general 
sensibility,  common  to  every  thing  that  has  life;  it 
has  no  peculiar  organ,  and  is  found  universally 
.     diffused  in  living  parts,  animal  or  vegetable*. 
'Voluntary  and  sentient,  subordinate  to  perceptibility. 

CONTRACTILITY.      J  Involuntary  and  insensible,  corresponding  to  latent  sen- 
sibility.   Tonicity. 
^Involuntary  and  sentient. 
The  cause  of  this  last  modification  of  contractility,  appears  to  depend 
on  the  peculiar  organization  of  the  system  of  the  great  sympathetic 
nerves.     From  these  nerves,  the  heart,  the  digestive  canal,  Sec.  seem  to 
receive  the  power  of  exerting  sensible  contraction,  an  effect  produced  by 
the  direct  application  of  a  stimulus,  and  over  which  volition  has  no  con- 
troul,  as  will  be  stated  in  speaking  of  those  nerves. 

Sensibility  and  contractility  offer  a  vast  number  of  differences,  the  prin- 
cipal of  which  depend  on  the  age,  the  sex,  the  regimen,  the  climate,  the 
state  of  waking  or  of  sleep,  health  or  of  sickness,  on  the  relative  develope- 
ment  of  the  lymphatic,  cellular,  or  adipose  systems,  on  the  proportions 
which  exist  between  the  nervous  and  muscular  systems. 

In  the  first  place,  the  principle  of  sensibility  and  contractility  may,  in 
its  action,  be  likened  to  a  fluid  flowing  from  any  source  whatsoever, 
which  is  consumed,  repaired,  and  drained  by  use,  re-supplied,  or  exhaust- 
ed, equally  distributed,  or,  occasionally  concentrated  on  certain  organs. 

Secondly.  Sensibility,  like  contractility,  is  very  considerable  at  the  in- 
stant of  birth,  and  seems  to  diminish  more  or  less  rapidly  till  death. 

Thirdly.  The  liveliness  and  frequency  of  impressions  wear  it  out  very 
early.  It,  in  a  manner,  repairs  itself,  that  is,  recovers  its  original  deli- 
cacy, when  the  sentient  organs  have  been  long  at  rest.  Thus, an  epicure, 
whose  taste  has  grown  dull  with  high  living,  will  recover  all  its  accuracy, 
if  during  several  months,  instead  of  spiced  ragouts  and  spiritous  liquors, 
he  lives  on  dry  bread  and  plain  water.  In  like  manner,  contractility  be- 
comes exhausted  in  the  muscles  which  are  too  long  employed,  and  it  is 
recovered  during  the  repose  of  sleep. 

Fourthly.  The  following  is  an  instance  of  the  manner  in  which  sensi- 
bility becomes  concentrated  on  one  organ,  and  appears  to  forsake  the 


See  Note  at  p.  17. 


31 

others  :  when  the  venereal  excitement  is  in  its  highest  degree,  animals 
under  its  influence  receive  blows  and  stings  without  pain.  Domestic 
animals  in  that  condition,  are  often  ill  treated,  without  appearing  to  feel 
what  is  done  to  them.  If  the  hind  legs  of  the  toad  are  cut  off,  at  the  time 
that  he  is  holding  the  female  firmly  embraced,  and  is  pouring  his  prolific 
seminal  fluid  on  the  ova  which  are  issuing  at  her  anus,  he  does  not  lose 
his  hold,  he  seems  insensible  to  every  other  sensation;  as  a  man  who  is 
taken  up  with  one  thought,  and  absorbed  in  reflexion,  is  scarcely  diverted 
from  it  by  any  means  that  can  be  employed.  When  during  the  influence 
of  satyriasis,  the  vital  power  is  carried  to  excess  in  the  penis,  patients 
have  been  known,  (as  we  are  told  by  Aetius)  to  cut  off  both  their  testicles, 
without  suffering  the  pain  usually  attending  so  severe  an  operation.  It 
is  by  this  law  of  sensibility,  that  we  are  to  explain  the  observation  of 
Hippocrates,  that  two  parts  of  the  body  cannot  be  in  pain  at  the  same 
time.  If  two  pains  come  on  at  once,  the  more  violent  prevents  the  slight- 
er from  being  felt;  Arribo partes  non  possunt  dolore  simul.  Duobus  dolori- 
bus,  simul  orientibus,  vehementior  obseurat  alterum.  (Hipp.)  In  cases  of 
scrophulous  swellings,  the  parts  are  observed  to  inflame,  to  become  pain- 
ful, and  suppuration  occurs  but  rarely  in  every  part  at  once,  if  the  case  is 
serious  and  attended  with  acute  pain.  The  germ  of  a  disease  or  of  a 
slighter  affection,  may  sometimes  remain  dormant  under  a  greater  pain. 
I  was  once  overturned  in  a  carriage,  from  the  awkwardness  of  a  coach- 
man, the  windows  were  broken  and  my  wrists  sprained.  The  right  wrist 
which  had  suffered  most,  swelled  first ;  I  employed  the  proper  treatment, 
and  when  at  the  end  of  a  wgpk,  the  swelling  and  the  pain  had  almost  com- 
pletely ceased,  and  the  right  hand  was  beginniug  to  recover  its  suppleness 
and  flexibility,  the  left  wrist  swelled  and  in  its  turn  became  pained  ;  two 
complaints,  if  they  may  be  called  such,  appeared  in  succession,  and  sepa- 
rately went  through  their  regular  course*. 

The  perfection  of  one  sense  is  never  obtained  but  at  the  expense  of  an- 
other ;  the  blind  who  bestow  more  attention  on  the  sensations  communi- 
cated by  the  sense  of  touch  and  of  hearing,  often  astonish  us  by  the  deli- 
cacy of  these  organs,  so  that,  as  has  been  observed,  those  who,  to  improve 
the  human  voice,  have  dared  to  mutilate  their  fellow-creatures,  by  de- 
priving them  of  the  organs  of  generation,  might  have  bethought  thetn- 

*  John  Hunter  maintains  from  theory,  the  position  that  no  two  different  fevers  can 
take  place  at  the  same  time  in  the  constitution,  but  that  if  the  two  causes  of  disease 
exist  together,  the  diseases  themselves  must  be  vicarious  ;  and  he  verifies  Ms  reason- 
ings from  experience. 

On  Thursday,  the  16th  of  May,  1775,  I  inoculated  a  gentleman's  child,  and  it  was 
•vedthat  I  made  pretty  large  punctures.  On  the  Sunday  following,  viz.  the  nine- 
teenth, he  appeared  to  have  received  the  infection,  a  small  inflammation  or  redness  ap- 
pearing round  each  puncture,  and  a  small  tumour.  On  the  twentieth  and  twenty-first, 
the  child  was  feverish,  hut  I  declared  that  it  was  not  the  variolous  fever,  as  the  inflam- 
mation had  not  at  all  advanced  since  the  nineteenth.  On  the  twenty-second  a  consider- 
ible  eruption  appeared,  which  was  evidently  the  measles,  and  the  sores  on  the  anus 
appeared  to  go  back,  becoming  less  inflamed. 

"  On  the  twenty-third  he  was  very  full  of  the  measles ;  but  the  punctures  on  the  arms 
were  in  the  same  state  as  on  the  preceding  day. 

"  On  the  twenty-fifth,  the  measles  began  to  disappear,  on  the  twenty-sixth  andtwen 
seventh,  tbe  punctures  began  again  to  look  a  little  red.  On  the  tw*»nti7.«;«*u  +K~  :_ 

^animation  inerpas^rl.   nnrl   thf>rf»  iiroo    o   i;«-*1^   ,  r 1          f\ 


in- 


selves  of  putting;  out  their  eyes,   to  render  them  more  sensible  to  the 
sweet  impressions  of  harmony. 

Fifthly.  Duringsound  sleep,  the  exercise  of  the  percipient  faculty,  and 
that  of  voluntary  contractility,  are  entirely  suspended.  During  that  state, 
it  seems  as  if  some  covering  were  thrown  over  the  sentient  extremities. 
We  know  how  hard  the  hearing  becomes,  how  dull  the  senses  of  smell  and 
of  taste  become,  how  dim  the  sight,  a  cloud  spreading  before  the  eyes, 
the  moment  we  are  fallen  asleep.  Fir  quidam.  exquisitissima  sensibilitate 
prsedituS)  semi  consopitus  coibat ;  huic^  ut  si  velamento  levi  glans  obductus 
fuisse,  sensus  volufitatis  referebatur. 

Sixthly.  Sensibility  is  more  lively,  and  more  easily  excited  in  the  in- 
habitants of  warm  climates  than  in  those  of  northern  regions.  What  a 
prodigious  difference  there  is,  in  that  respect,  between  the  native  of  Ger- 
many and  of  the  southern  provinces  of  France.  Travellers  tell  us,  that 
there  are  in  the  neighbourhood  of  the  poles,  natives,  so  little  endowed 
with  sensibility,  that  they  feel  no  pain  from  the  deepest  wounds.  The  in- 
habitants of  the  coast  of  North  America,  if  we  may  believe  the  testimony 
of  Dixofi  and  Vancouver,  thrust  into  the  soles  of  their  feet,  sharp  nails 
and  pieces  of  glass,  without  feeling  the  slightest  uneasiness.  On  the  con- 
trary, the  slightest  prick  from  a  thorn,  for  instance,  in  the  foot,  is  in  the 
strongest  African,  frequently  followed  by  convulsions  and  locked  jaw. — 
The  impression  of  the  air  is  alone  sufficient  to  produce  the  same  accident 
in  the  negro  children  in  the  colonies,  the  greater  number  of  whom  die  of 
locked  jaw,  a  few  days  after  birth. 

Montesquieu*  very  justly  observed  this  difjpence  which  exists  in  the 
sensibility  of  the  southern  and  northern  nations,  and  he  says  of  the  latter, 
that  "  if  you  would  tickle  you  must  flay  them." 

Now,  as  the  imagination  is  always  proportioned  to  the  sensibility,  all 
the  arts  that  are  cultivated  and  brought  to  perfection,  only  by  the  exer- 
cise of  that  faculty,  will  flourish  with  difficulty  near  the  icy  polar  regions, 
unless  the  powerful  influence 'of  climate  be  counteracted  by  well  directed 
moral  and  physical  causes. f 

Man  is  of  all  beings,  the  one  that  most  powerfully  resists  the  influence 
of  external  causes  :  and  although  the  influence  of  climate  is  sufficient  to 
modify  his  external  appearance,  so  as  to  lead  to  a  division  of  the  species 
into  several  distinct  varieties  or  kinds,  this  superficial  impression  is  very 


*  This  philosopher  has  borrowed  from  the  father  of  physic,  one  of  his  most  brilliant 
and  paradoxical  opinions.  In  his  conception,  warm  climates  are  the  seat  of  despotism, 
and  the  cold,  the  seat  of  liberty.  This  error  is  completely  refuted  in  the  profound  and 
philosophical  work  of  Volney  on  Egypt  and  Syria.  He  shows,  that  what  Montesquieu 
has  said  of  cold  climates  applies  to  mountainous  regions,  while  a  champaign  is  more 
favourable  to  the  establishment  of  tyranny.  Hippocrates  had  said  of  the  Asiatics,  that 
their  being  less  warlike  than  the  Europeans,  depended  on  the  differences  of  climate, 
and  likewise  on  the  despotic  form  of  their  government.  And  he  observes,  that  men, 
who  do  not  enjoy  their  natural  rights,  but  whose  affections  are  controuled  by  masters, 
cannot  feel  the  bold  passion  of  war.  See  Chap.  XI.  on  the  Varieties  of  the  Hnman 
Species  — Author's  JVote. 


fices 
modo  in 

rante,  hebes  et  langmdus  factus,  membra  sua  zegre  trahit,  ac  ille,  qui  ut  frigido  aqui- 
lone,  cursu  glaciali,  se  exercet,  universum  corpus  firmus,  mobilis,  expeditus !  GREG- 
ORY Consp.Med.  Theorei — [Got/man.] 


different  from  the  great  alterations  to  which  other  beings  are  exposed, 
from  the  mere  change  of  climate.  Man  is  every  where  indigenous,  and 
exists  in  all  climates;  while  the  plants  and  animals  of  the  equator  lan- 
guish and  die  when  conveyed  to  the  polar  regions.  From  the  flexibility 
of  his  nature,  man  enjoys  the  power  of  adapting  himself  to  the  most  op- 
posite situations,  of  establishing,  between  them  and  himself,  relations 
compatible  with  the  preservation  of  life.  Nevertheless,  it  is  not  without 
difficulty  that  man  undergoes  these  changes,  and  accustoms  himself  to 
new  impressions.  The  periodical  return  of  the  season  determines  that 
of  certain  derangements,  to  which  the  animal  oeconomy  is  subject.  The 
same  diseases  manifest  themselves  under  the  influence  of  the  same  tem- 
perature, and  to  use  an  ingenious  comparison,  resemble  those  birds  of 
passage  which  visit  us  ut  stated  seasons  of  the  year.  Thus  hemorrhages 
and  eruptive  affections  come  on  with  the  return  of  the  spring,  summer 
comes  attended  by  bilious  fevers,  autumn  brings  on  a  return  of  dysen- 
teric affections,  and  winter  abounds  in  inflammation  of  the  lungs  and 
other  parts.  The  influence  of  climate  on  the  human  body,  does  not  show 
itself  merely  in  occasioning  epidemic  diseases,  the  consideration  of  which 
led  to  the  establishing  what  physicians  call  medical  constitutions.  This  in- 
fluence operates  on  man  in  health,  as  well  as  in  sickness;  and  to  say 
nothing  of  the  alterations  which  our  moral  nature  experiences  from  the 
tendency  of  love,  rendered  more  impetuous  with  the  return  of  spring,  or 
of  melancholy,  to  which  nervous  people  are  often  subject  towards  the 
end  of  autumn,  when  the  trees  are  shedding  their  leaves,  the  increase  of 
growth  is  particularly  remarkable  at  the  time  of  the  first  growth  of 
plants,  as  was  observed  again  and  again,  by  a  friend  of  mine,  physician 
to  a  large  seminary. 

Seventhly.  Sensibility  is  greater  in  women  and  children  ;  their  nerves* 
are  likewise  larger  and  softer,  in  proportion  to  the  other  parts  of  the 
body.  In  general,  the  principle  of  sensibility  seems  to  decrease,  in  pro- 
portion as  it  has  contributed  to  the  developement  of  the  acts  of  life ;  and 
the  power  of  being  impressed  by  external  objects,  diminishes  gradually 
with  age,  so  that  there  is  a  period  of  decrepid  old  age,  at  which  death  ap- 
pears a  necessary  consequence  of  the  complete  exhaustion  of  that  princi- 
ple. In  short,  as  I  have  said  in  describing  the  progress  of  death,  at  its 
approach,  sensibility  shows  increase  of  activity  and  liveliness,  as  if  its 
quantity  required  to  be  completely  exhausted,  before  the  termination  of 
existence,  or  as  if  the  organs  made  a  last  effort  to  cling  to  life. 

The  developement  of  the  cellular  and  adipose  substance,  diminishes 
the  energy  of  sensibility,  the  extremities  of  the  nerves  being  more  cover- 
ed, and  therefore  not  so  immediately  applied  to  the  objects,  the  impres- 
sions which  when  felt,  are  more  obscure.  The  fat  operates  on  the  nerves, 
as  wool  would  do  on  vibrating  chords,  if  wrapped  round  them,  to  fix 
them,  to  prevent  their  quiverings,  and  stop  their  vibrations. 

Very  nervous  women  are  very  thin ;  persons  of  much  sensibility  have 
seldom  much  fleshiness.  Swine,  in  which  the  nerves  are  covered  by  a 
thick  layer  of  fat,  are  the  most  insensible  of  all  animals.  The  suscepti- 
bility of  the  nerves  may  be  diminished,  and  their  sensibility  blunted  by 
pressure.  The  application  of  a  bandage  firmly  rolled  round  the  body  and 
limbs  of  an  hysterical  woman,  will  diminish  the  violence  of  her  fits.  In 


*  Their  voluntary  nerves; 


34 

dressing  wounds  affected  with  what  is  called  the  hospital  gangrene,  i 
have  often  relieved  the  pain,  by  desiring  an  assistant  to  apply  firm  pres- 
sure above  the  sore. 

Ninthly.  There  exists  between  the  force  of  the  muscles,  and  the  sen- 
sibility of  the  nerves;  between  the  sensible  energy  and  the  force  of  contrac- 
tion, a  constant  opposition,  so  that  the  most  vigorous  athletics,  whose  mus- 
cles are  capable  of  the  most  prodigious  efforts,  and  of  the  most  powerful 
contractions,  are  but  slightly  affected  by  impressions,  and  are  with 
difficulty  roused  into  action,  as  we  have  explained  in  giving  a  history  of 
the  nervous  and  muscular  temperaments,  which  are  characterized  by  this 
difference.  Hence,  man  has  more  sensibility  than  the  quadrupeds, 
although  his  nerves  are  smaller  than  theirs,  which  seem  destined  to 
set  the  muscles  in  action,  and  to  serve  as  nerves  of  motion,  rather  than 
of  sensation. 

There  is  no  muscular  fibre,  however  minute,  in  which  we  are  not  oblig- 
ed to  admit  the  existence  of  a  small  nervous  filament,  to  which  it  probably 
owes  the  power  of  contracting;  contractility,  at  least  voluntary  contrac- 
tility, does  not  appear  to  be  inherent  in  the  muscular  fibre,  nor  independ- 
ent of  the  nerves,  through  the  medium  of  which,  the  will  determines  the 
action  of  the  muscles ;  and  if  these  last  organs  were  insulated,  contract 
on  the  direct  application  of  a  stimulus,  is  there  not  reason  to  suspect,  that 
this  stimulus  acts  on  that  portion  of  nerves  which  remains  in  the  muscle, 
after  it  has  been  insulated,  and  which  is  intimately  united  in  its  fibres  ? 
The  animals  which  have  no  distinct  nervous  system,  possess  at  once  in 
all  their  parts,  sensibility  and  contractility ;  these  two  properties  become 
blended  in  the  organs,  as  well  as  in  the  phenomena  of  life,  and  can 
be  perceived  separate,  only  by  a  pure  abstraction  of  the  mind,  which 
considers  in  succession  the  impression  produced  on  these  beings,  and 
the  motion  of  their  substance,  which  is  an  immediate  consequence  of 
that  impression. 

We  will  not  enter  any  further  into  a  consideration  of  the  laws  and  phe- 
nomena of  the  vital  properties,  for  fear  of  being  led  into  useless  repeti- 
tions, when  we  come  to  the  history  of  the  functions  over  which  they  pre- 
side. We  will  conclude  what  relates  to  them,  by  presenting  the  two 
most  important  features  of  their  history,  I  mean,  sympathy  and  habit. 

§VII.    OF  SYMPATHY. 

There  exist  among  all  the  parts  of  the  living  body,  intimate  relations; 
all  correspond  to  each  other,  and  carry  on  a  reciprocal  intercourse  of 
sensations  and  affections.  These  links  which  unite  together  all  the  or- 
gans, by  establishing  a  wonderful  concurrence,  and  a  perfect  harmony 
among  all  the  actions  that  take  place  in  the  animal  oeconomy,  are  known 
under  the  name  of  Sympathies.  The  nature  of  this  phenomenon  is  yet 
unknown;  we  know  not  why,  when  a  part  is  irritated,  another  very  dis- 
tant part  partakes  in  that  irritation,  or  even  contracts:  we  do  not  even 
understand  what  are  the  instruments  of  sympathy,  that  is,  what  are  the 
organs  which  connect  two  parts,  in  such  a  manner,  that  when  one  feels 
or  acts,  the  other  is  affected.  But  though  beyond  explanation,  sympathy 
is  not  the  less  important  in  the  oeconomy  of  living  beings ;  and  these 
connexions  between  remote  parts,  constitute  one  of  the  most  remark- 
able differences  between  those  beings  and  inorganic  bodies.  No- 
thing similar  is  observable  in  dead  or  inanimate  nature,  in  which  all 


35 

things  are  connected  together,  only  by  palpable  and  material  links;  here 
the  chain  is  invisible,  the  connexion  evident,  the  cause  occult,  and  the 
effect  apparent. 

Whytt  has  clearly  shown,  that  the  nerves  cannot  be  considered  as  the 
exclusive  instruments  of  sympathy*,  since  several  muscles  of  a  limb 
which  receive  filaments  from  the  same  nerve,  do  not  sympathize  together, 
while  there  may  be  a  close  and  manifest  relation  between  two 
parts,  of  which  the  nerves  have  no  immediate  connexion,  since  each  ner- 
vous filament  having  one  of  its  extremities  terminating  in  the  brain,  the 
other,  in  the  part  to  which  it  is  sent,  remains  distinct  from  those  of  the 
same  trunk,  and  does  not  communicate  with  them. 

Sympathies  may  be  distinguished  into  different  kinds.  In  the  first 
place,  two  organs,  which  execute  similar  functions; — the  kidnies  may 
supply  each  other's  office.  When  the  uterus  is  in  a  state  of  pregnancy, 
the  breasts  participate  inits  condition,  and  there  is  determined  into  them 
a  flow  of  blood  necessary  to  the  secretion  which  is  to  take  place. 
Secondly.  The  continuity  of  membranes  is  a  powerful  source  of  sympa- 
thy. The  presence  of  worms  in  the  bowels,  determines  an  uneasy  itch- 
ing around  the  nostrils.  When  there  is  a  stone  in  the  bladder,  a  certain 
degree  of  itching  is  felt  at  the  extremity  of  the  glans.  The  secretion 
of  several  fluids  is  determined  in  the  same  manner:  thus,  the  presence  of 
food  in  the  mouth,  causes  at  the  extremity  of  the  parotid  duct,  an  irri- 
tation which  extends  to  the  parotid  glands,  calls  them  into  action,  and 
increases  their  secretion.  Thirdly.  If  the  pituitary  membrane  is  irrita- 
ted, the  diaphragm  with  which  it  has  no  immediate  organic  connexion, 
nervous,  vascular,  or  membranous,  contracts  and  occasions  sneezing.  Is 
not  this  sympathy  one  of  those  which  Haller  ascribed  to  a  re-action  of 
the  sensorium  commune  ?  If  the  impression  produced  on  the  olfactory 
nerves  by  snuff,  is  too  powerful,  the  uneasy  sensation  is  transmitted  to 
the  brain,  which  determines  towards  the  diaphragm,  a  quantity  of  the 
principle  of  motion  sufficient  to  enable  that  muscle  suddenly  to  contract 
the  dimensions  of  the  chest,  so  as  to  expel  a  column  of  air,  that  may  de- 
tach from  the  pituitary  membrane,  the  substances  that  are  a  cause  of  un- 
easiness to  it.  Fourthly.  Does  not  the  principle  of  life  seem  to  controul 
at  pleasure  the  phenomena  of  sympathy  ?  The  rectum,  when  irritated  by 
the  presence  of  the  excrements,  contracts ;  what  cause  determines  the  ac- 
cessory and  simultaneous  action  of  the  diaphragm  and  abdominal  mus- 
cles ?  Does  this  connexion  depend  on  organic  communications  ?  Why, 
then,  is  not  the  sympathy  reciprocal,  and  why  does  not  the  rectum  con- 
tract, when  the  diaphragm  is  irritated  ?  Fifthly.  Can  the  repeated  habit 
of  the  same  motions  explain  the  harmony  which  is  observed  in  the  sym- 
metrical organs  ?  Why,  when  our  sight  is  directed  to  an  object,  placed 


*  Whytt's  opinion  must  be  cautiously  received,  for  the  following  reason.  We  know 
of  no  mode  by  which  impressions  can  be  communicated,  except  through  the  medium  of 
the  nerves.  It  would  then,  be  a  much  safer  conclusion,  to  state  that  we  are  ignorant 
of  the  exact  manner  in  which  sympathies  are  affected  by  the  nerves,  than  to  resort  to  a 
supposed  cause.  We  do  not  see  any  particular  necessity  that  nerves  going  to  several 
muscles  of  a  limb  should  cause  them  uniformly  to  sympathise.  In  the  bi-ain  we  find 
nerves  endowed  with  the  most  dissimilar  powers  arising  almost  from  the  same  point 
and  from  the  same  cerebral  substance.  For  a  sketch  of  some  nervous  communications 
and  an  explanation  of  certain  sympathies,  see  a  paper  by  John  D.  Godman^  M.  D.  in 
the  Philad.  Journal  of  Med.  and  Phys.  Sciences,  Vol.  VH,  p.  237- 


laterally,  does  the  rectus  externus  of  the  eye  on  that  side,  act  at  the  same 
time  as  the  rectus  interims  of  the  other  eye?  The  indispensable  utility 
of  this  phenomenon,  in  keeping  a  parallelism  of  the  axis  of  vision  is  very 
obvious,  but  who  can  assign  the  cause?  Why  are  rotatory  motions, 
in  different  directions,  performed  with  so  much  difficulty  by  the  arm 
and  leg  of  the  same  side  of  the  body.  Can  it  be  called  a  just  idea  of 
the  innumerable  varieties  of  this  phenomenon,  and  of  its  frequent  ano- 
malies, to  say,  with  Rega,  that  there  are  sympathies  of  action  or  of  con- 
tractility (consensus  actionum)  sympathies  of  sensibility  (consensus  passio- 
num. ) 

All  these  difficulties  render  it  pardonable  in  Whytt,  to  have  consider- 
ed the  soul  as  the  sole  cause  of  sympathy?  which  was,  in  fact,  a  modest 
avowal  of  the  difficulty  of  explaining  the  subject.  We  are  not  justifi- 
ed in  considering  sympathy  as  an  anamolous  action,  as  an  aberration 
of  the  vital  power*.  Can  it  be  said,  that  the  natural  order  of  sensibility 
and  irritability  is  inverted,  in  the  sympathetic  erection  of  the  clitoris  and 
of  the  nipple,  or  in  the  turgesence  of  the  breasts,  determined  by  the  gra- 
vid state  of  the  uterus? 

It  is  by  means  of  sympathy  that  all  the  organs  concur  in  the  same  end, 
and  yield  each  other  mutual  assistance.  It  affords  us  the  means  of  ex- 
plaining, how  an  affection,  at  first  local  or  limited  in  its  extent,  spreads 
and  extends  to  all  the  systems ;  it  is  thus  that  every  morbid  process  is 
carried  on.  The  diseases  termed  general,  always  originate^  through  the 
medium  of  association,  in  the  insulated  affection  of  an  organ  or  a  system 
of  organs. 

In  fact,,  the  affections  which  appear  to  us  most  complex,  in  the  number, 
the  variety,  and  the  dissimilarity  of  their  symptoms,  consist  of  only  one, 
or  of  a  small  number  of  primitive  or  essential  elements,  all  the  rest  are 
accessory,  and  depend  on  numerous  sympathies  ot  the  affected  organ, 
with  the  other  organs  of  the  animal  (Economy.  Thus,  if  the  stomach  is 
the  seat  of  irritation,  from  foulness  of  its  contents,  pains  of  all  kinds 
come  on,  but  especially  in  the  head  and  limbs,  with  a  burning  heat,  nau- 
sea, loss  of  appetite,  anxiety,  and  these  symptoms  constitute  a  disease, 
which  appears  to  affect  the  whole  system. 

To  go  on  with  the  same  illustration,  the  stomach,  when  oppressed  by 
irritating  substances,  contracts  spontaneously  to  get  rid  of  them.  The 
universal  disturbance  which  their  presence  occasions,  seems  directed  to- 
wards the  same  end,  as  if  the  suffering  organ  called  upon  all  the  others  to 
assist  in  relieving  it. 

These  synergies,  or  aggregate  motions,  tending  to  one  end,  and  arising 
out  of  the  laws  of  sympathy,  constitute  the  diseases  termed  general,  as 

*  Sympathy  may  be  considered  that  state  v/hich  an  organ  or  texture  presents,  which 
hokls  a  certain  relation  to  the  condition  which  characterises  another  orgun  or  texture* 
in  health  or  in  disease :  or  it  may  be  viewed  as  a  certain  relative  state  of  the  vital  power 
as  it  exists  in  separate  organs  or  textures  ;  as  when  one  part  is  excited  another  par- 
ticipates in  the  change  and  evinces  a  similar  feeling-,  motion,  or  function. 

Sympathies  may  be  classed  into  the  reflex  and  direct.  The  former  may  be  chiefly 
referred  to  the  cerebral  nerves  and  to  the  reaction  of  the  sensorium,  as  when  the 
Schneiderian  membrane  is  irritated  the  diaphragm  is  affected  in  consequence  of  the 
excitement  conveyed  to  the  brain,  and  thence  to  this  muscle  by  means  of  its  voluntary 
nerves/  The  latter  class  takes  place  independently  of  the  sensorium,  and  arises  from 
the  ramification  and  distribution  of  the  ganglial  nerves,  especially  those  which  are  sent 
to  the  Muscular  system.  For  the  elucidation  of  this  subject,  sec  APPENDIX,  Note  E. 


us  well  as  the  greater  part  of  those  which  are  called  local.  It  is  by  means 
of  them,  and  through  these  kinds  of  organic  insurrections,  if  we  may  be 
permitted  to  use  that  expression,  which  perfectly  expresses  our  meaning, 
that  nature  struggles  with  advantage,  and  rids  herself  of  the  morbific 
principle,  or  of  the  cause  of  the  disease;  and  the  art  of  exciting  and  di- 
recting these  actions,  furnishes  the  materials  of  the  most  important  doc- 
trines of  the  practice  of  medicine.  I  have  used  the  terms  excite  and  di- 
rect; for  it  is  necessary  at  times  to  increase,  at  others  to  diminish  their 
intensity  and  force,  and  on  some  occasions  to  excite  them,  when  nature, 
overwhelmed  under  disease,  is  almost  incapable  of  re-action.  This  last 
circumstance  belongs  to  the  diseases  of  the  most  dangerous  kind,  if  we 
include  those  in  which  the  efforts  of  nature,  though  marked  by  a  certain 
degree  of  energy,  are  without  connection,  or  consent,  and  frustrated  by 
their  want  of  coherence.  The  character  of  these  affections  was  first 
well  expressed  by  Selle,  who  substituted,  for  the  term  malignant,  which 
used  to  be  applied  to  them  without  any  precise  meaning,  that  of  ataxic,* 
which  points  out  very  correctly,  the  want  of  order,  and  the  irregular  suc- 
cession of  their  symptomsf. 

A  knowledge  of  symptoms  is  of  the  highest  importance  in  the  practice 
of  medicine!.  When  we  wish  to  avert  an  irritation  fixed  in  a  diseased 
organ,  experience  and  observation  prove,  that  it  is  on  the  organ  which 
bears  to  it  the  closest  sympathetic  connexions,  that  it  is  useful  to  apply 
medicines  intended  to  excite  counter-irritation. 

This  might  perhaps  be  the  fittest  place  to  inquire  into  the  nature  of 
those  concealed  relations  which  draw  men  together,  and  of  those  aver- 
sions which  prevent  their  union ;  to  discover  the  causes  of  those  secret 
impulses  which  lead  two  beings  towards  each  other;  and  force  them  to 
yield  to  an  irresistible  propensity.  We  might  inquire  into  the  reason  of 
antipathy,  and  in  a  word,  establish  the  complete  theory  of  moral  sen- 
timents and  affections.  Such  an  undertaking  is  greatly  above  our 
strength,  and  besides,  does  not  absolutely  belong  to  our.  subject.  It  would 
require  a  considerable  time,  and  whoever  should  undertake  it,  would  be 
in  considerable  danger  of  losing  his  way  at  every  step,  in  the  extensive 
field  of  conjectures§. 

*  a.r<t&t,  confusion  ;  from  a,  priv.  anil  TAC.IS,  order. — Godman. 

j  Symptomala  ncn'osa,  nee  inter  se,  neqne  causis  manifestis  rcspondentia.  Ordo  tert. 
actatse,  C.  G.  Selle.  Rudimenta  pyretologix  methodic*. 

t  This  information  may  be  obtained  by  consulting1  the  works  of  the  ancients,  and 
especially  of  Hippocrates,  who  appears  to  have  felt  all  the  importance  of  this  subject. 
Among  the  moderns,  Vanhelmont,  Baglivi,  Rega,  Whytt,  Hunter,  Barthez,  and  Bichat, 
have  collected  on  this  subject,  a  great  number  of  facts  obtained  from  experiments  on 
animals,  and  especially  from  observations  on  diseases. — Authors  Note. 

§  That  law  of  the  animal  oeconomy,  termed  "  sympathy  or  consent  of  parts,"  is  a  very 
important  one,  and  has  hitherto  been  too  much  overlooked  in  our  speculations  respect- 
ing- the  phenomena  of  health  and  disease.  There  are  indeed,  not  wanting  some,  who 
have  aflected  scepticism  as  to  the  very  existence  of  such  a  law — True  it  is,  that,  at  pre- 
sent, we  have  no  very  distinct  intelligence  relative  to  the  nature  of  the  principle  ;  but 
are  we  on  this  account  to  question  its  existence  ?  With  equal  reason  might  we  doubt 
of  the  sensibility  or  irritability  of  the  body.  By  whom  has  the  precise  nature  of  either 
of  these  qualities  of  vital  matter  been  demonstrated  ?  Yet  we  are  persuaded  of  their 
existence  from  the  phenomena  which  they  exhibit,  and  it  is  by  the  same  description  of 
evidence  that  we  ar*,  or  ought  to  be,  assured  of  the  existence  of  sympathy. 

"  Causa  latct,  vis  est  noiissima." 
Of  the  manner  in  which  sympathetic  impressions  are  extended  as  well  as  of  the  cause 


§  VII.    OF  HABIT. 

It  is  easier  to  teel  the  meaning  of  this  term  than  to  define  it.  Habit, 
however,  may  be  said  to  consist  in  the  frequent  repetition  of  certain  acts, 
or  certain  motions,  in  which  the  whole  body  participates,  or  only  some 
of  its'parts.  The  most  remarkable  effect  of  habit,  is  to  weaken  after  a 
time  the  sensibility  of  organs.  Thus,  a  catheter  introduced  along  the 
urethra,  and  allowed  to  remain  there,  causes  during  the  first  day,  rather 
sharp  pain,  on  the  second  day,  it  feels  less  uneasy  ;  on  the  third  day  it  is 
only  troublesome;  and  on  the  fourth,  the  patient  scarcely  feels  it.  The 
use  of  snuff  at  first  increases  the  secretion  of  mucus  in  the  nose,  but 
if  continued  a  certain  time,  it  ceases  to  affect  the  pituitary  membrane, 
and  the  secretion  would  diminish  considerably  but  for  the  practice  of  in- 
creasing daily  the  quantity  of  that  acrid  powder;  the  presence  of  a  ca- 
nula  in  thenasalduct,  after  the  operation  for  fistula  lachrymalis,  increases 
at  first  the  mucous  secretion  of  that  canal  ;  but  in  proportion  as  it 
becomes  accustomed  to  the  extraneous  body,  the  secretion  returns  to  its 
natural  condition. 

It  is  only  by  our  sensations  that  we  are  aware  of  our  existence.  Life, 
to  make  use  of  the  figurative  language  of  system,  of  a  modern  writer, 
consists  in  the  action  of  stimuli  on  the  vital  powers.  (Tola  vita,  quanta 
est,  consistit  in  stimulo,  et  vi  vitali.  Brown.)  Sentient  beings  feel  a  conti- 


ofthe  more  intimate  consent  which  exists  between  parts,  we  are  not  accurately  in- 
formed.  Those  sympathies  which  prevail  among  the  various  viscera  of  the  abdomen, 
and  between  them  and  the  head,  neck  and  contents  of  the  thorax,  may,  perhaps, 
be  explained  by  the  extensive  anastomoses  of  the  intercostals  with  almost  all  the 
nerves  which  proceed  from  the  spinal  marrow.  But  there  are  many  other  sympa- 
thies, equally  conspicuous,  between  parts,  the  nerves  of  which  (apparently)*  have 
not  the  slightest  connexion.  Here  it  appears  that,  either  by  the  co-operation  of 
different  organs  in  the  performance  of  a  function,  as  in  the  complex  apparatus  sub- 
servient to  respiration,  or  from  similarity  of  structure,  parts,  though  detached,  be- 
ing prone  to  be  affected  by  the  same  cause,  as  the  parotid  glands  and  testes  in  the 
7nale,  and  the  same  gland  with  the  mammae  in  the  female,  the  habit  of  acting  in  unison 
is  acquired,  and  sometimes  confirmed.  This  habit  of  concerted  action  is  called  associ- 
ation, and  has  been  adopted  as  a  principle  by  Locke,  by  Hartley,  and  by  Darwin,  to  ac- 
count for  the  connexion  which  is  discernable  in  many  of  the  motions  of  the  body,  as  well 
as  in  the  operations  of  the  mind.  Both  the  sound  and  morbid  states  of  the  system  pre- 
sent numerous  instances  of  these  associated  actions,  some  of  which  are  constant  and 
uniform,  while  others  are  occasional,  and  anamolous,  produced  as  it  were  accident- 
ally. 

The  principle  of  sympathy  extends  throughout  the  body,  every  portion  of  it  being 
susceptible  of  associative  actions,  by  which  means  the  different  parts  are  linked  toge- 
ther so  as  to  form  one  whole. — Certain  organs  however,  are  more  eminently  endowed 
with  the  property,  as  the  uterus,  the  brain,  and  especially  the  stomach.  This  last  vis- 
cus  constitutes  the  chief  medium  of  sympathetic  connexion.  With  it,  the  brain,  thtf 
organs  of  sense,  and  deglutition,  the  whole  of  the  thoracic  and  abdominal  viscera; 
the  parts  of  generation  in  each  sex,  the  blood  vessels,  the  joints,  the  exterior  surface, 
and  in  short  all  the  parts  of  the  system  however  minute,  maintain  a  close  and  intimate 
sympathy.  Placed  in  the  middle,  the  stomach  is  the  centre  of  the  greatest  sphere  of 
sympathy.  But,  besides  this  great  sphere,  there  are  many  subordinate  ones,  which  our 


narrow  limits  will  not  permit  us  particularly  to  designate  :  as  for  example,  the  uterus, 
with  the  different  portions  of  its  own  system,  the  ovaries,  the  mammae,  &c.  &c.    It  was 

on  account  of  its  vast  dominio  "x **-*'—<*  — — -*^~-    *»•-«•  v— 

Helmont  selected  the  stomac 
Stahl  and  Mcholte — Chapmai 


on  account  of  its  vast  dominion  over  the  system,  by  its  multiplied  sympathies,  that  Van 
Helmont  selected  the  stomach  as  the  residence  of  his  archxuz,  the  anima  medica}  of 


39 

nual  necessity  of  renewed  emotions :  all  their  actions  tend  to  the  obtain- 
ing agreeable  or  disagreeable  sensations;  for  in  the  absence  of  other  sen- 
sations, pain  is  sometimes  attended  \vith  enjoyment.  Those  who  have 
exhausted  every  kind  of  enjoyment,  and  who  have  had  no  pleasures  un- 
gratified,  are  led  to  suicide  from  a  weariness  of  life;  who  can  live,  when 
all  power  of  feeling  is  gone? 

The  following  is  the  most  extraordinary  and  remarkable  instance 
known,  of  the  manner  in  which  habit  and  a  frequent  repetition  of  the 
same  impressions,  wear  out  by  degrees  the  sensibility  of  organs.  A  shep- 
herd, about  the  age  of  fifteen,  became  addicted  to  onanism,  and  to  such  a 
degree,  as  to  practise  it  seven  or  eight  times  in  a  day.  Emission  became 
at  last  so  difficult,  that  he  would  strive  for  an  hour,  and  then  discharge 
only  a  few  drops  of  blood.  At  the  age  of  six  and  twenty  his  hand  became 
insufficient,  all  he  could  do,  was  to  keep  the  penis  in  a  continual  state  of 
priapism.  He  then  bethought  himself  of  tickling  the  internal  part  of 
his  urethra,  by  means  of  a  bit  of  wood  six  inches  long,  and  he  would 
spend  in  that  occupation  several  hours,  while  tending  his  flock  in  the 
solitude  of  the  mountains.  By  a  continuation  of  this  titillation  for  six- 
teen years,  the  canal  of  the  urethra  became  hard,  callous,  and  insensible. 
The  piece  of  wood  then  became  as  ineffectual  as  his  hand;  at  last,  after 
much  fruitless  effort,  he  one  day,  in  despair,  drew  from  his  pocket  a 
blunt  knife,  and  made  an  incision  into  his  glans,  along  the  course  of  the 
urethra;  this  operation,  which  would  have  been  painful  to  any  ojK^else; 
was  in  him  attended  with  a  sensation  of  pleasure,  followed  by  a  copious 
emission.  He  had  recourse  to  his  new  discovery,  every  time  his  desires 
returned.  When  after  an  incision  into  the  cavernous  bodies  the 
blood  flowed  profusely,  he  stopped  the  hemorrhage,  by  applying  around 
the  penis  a  pretty  tight  ligature.  At  last,  after  repeating  the  same  pro- 
cess, perhaps  a  thousand  times,  he  ended  in  splitting  his  penis  into  two 
equal  parts,  from  the  meatus  urinarius  to  the  scrotum,  very  near  to  the 
symphysis  pubis.  When  he  had  got  so  far,  unable  to  carry  his  incision 
any  farther,  and  again  reduced  to  new  privations,  he  had  recourse  to  a 
piece  of  wood,  shorter  than  the  former  :  he  introduced  it  into  what  re- 
mained of  the  urethra,  and  exciting  at  pleasure  the  extremities  of  the 
ejaculatory  ducts,  he  provoked  easily  the  discharge  o^Semen.  He  con- 
tinued this  about  ten  years,  after  that  long  space  of  time,  he  one  day  in- 
troduced his  bit  of  wood  so  carelessly,  that  it  slipped  from  his  fingers  and 
dropped  into  the  bladder.  Excruciating  pain  and  serious  symptoms 
came  on.  The  patient  was  conveyed  to  the  Hospital  at  Narbonne.  The 
surgeon,  surprised  at  the  sight  of  two  penes  of  ordinary  size,  both  capa- 
ble of  erection,  and  in  that  stage  diverging  on  both  sides,  and  seeing  be- 
sides from  the  scars  and  from  the  callous  edges  of  the  division,  that  this 
conformation  was  not  congenital,  obliged  the  patient  to  give  him  an  ac- 
count of  his  life,  which  he  did,  with  the  details  which  have  been  related. 
This  wretch  was  cut  as  for  the  stone,  recovered  of  the  operation,  but 
died  three  months  after,  of  an  abcess  in  the  right  side  of  the  chest,  his 
phthisical  state  having  been  evidently  brought  on  by  the  practice  of 
onanism  carried  on  nearly  forty  years*. 

The  habit  of  suffering,  renders  us  in  the  end  insensible  to  pain;  but 
every  thing  in  this  world  is  balanced,  and  if  habit  lightens  our  evils,  by 


*  Chopart,  maladies  des  voies  urinaires.    Tome  II. 


40 

blunting  sensibility,  it  on  the  other  baud  drains  th  source  of  our  sweetest 
enjoyments.  Pleasure  and  pain,  these  two  extremes  of  sensation,  in  a 
manner,  approximate  to  each  other,  and  become  indifferent  to  him  who 
is  accustomed  to  them*.  Hence  arises  inconstancy,  or  rather  that  insa- 
tiable desire  of  varying  the  objects  of  our  inclinations,  that  imperious 
want  of  new  emotions;  hence  we  possess  with  indifference  what  was  pur- 
sued with  the  utmost  ardour  and  perseverance,  and  even  cease  to  be  im- 
pressed by  those  charms  which  once  held  us  captivated. 

A  striking  instance  of  the  powerful  influence  of  habit  on  the  action  of 
organs,  is  afforded  by  that  criminal,  who,  we  are  told  by  Sanctorius,  was 
taken  ill  on  being  removed  from  a  noisome  dungeon,  and  did  not  (recover 
till  he  was  placed  in  the  impure  air  to  which  he  had  been  long  accus- 
tomed. Mithridates,  that  formidable  rival  of  the  Roman  power,  dread- 
ing to  be  taken  alive  by  his  enemies,  tried  in  vain  to  put  an  end  to  his 
life,  by  taking  large  doses  of  the  most  subtle  poisons,  because  he  had 
long  inured  himself  to  their  actionf.  It  has,  therefore,  been  justly  said 
of  habit,  that  it  is  a  second  nature,  whose  laws  ought  to  be  respected. 

The  organs  of  generation  in  women,  in  consequence  of  their  lively 
sensibility,  are  in  an  especial  manner  submitted  to  the  powerful  influence 
of  habit.  The  womb,  after  a  miscarriage,  has  a  tendency  to  a  renewal  of 
the  same  occurrence,  when  the  same  period  of  pregnancy  recurs,  so  that 
the  greatest  precautions  ure  necessary  to  prevent  abortion  in  women, 
who  are  subject  to  it,  when  they  have  reached  the  month  in  which  they 
before  miscarried. 

May  not  death  be  considered  as  a  natural  consequence  of  the  laws  of 
sensibility  ?  Life,  depending  on  the  continual  excitement  of  the  living 
solids  by  the  fluids  which  moisten  them,  ceases,  because  the  parts  endow- 
ed with  sensibility  and  contractility,  after  long  habitude  of  the  impres- 
sions of  those  fluids,  lose  their  capacity  of  feeling  them.  Their  action 
gradually  extinguished,  would  perhaps  revive,  if  the  energy  of  the  sti- 
mulating power  were  increased. 

A  knowledge  of  the  power  of  habit,  is  a  useful  guide  in  the  application 
of  remedies,  the  greatest  part  of  which  operate  in  the  cure  of  diseases,, 
only  by  modifying  sensibility.  A  wound  in  which  lint  has  kept  up  the 
degree  of  inflammation  necessary  to  cicatrization,  becomes  insensible  to 
that  application,  the  parts  become  spungy  and  soft,  and  the  cure  is  pro- 
tracted. The  lint  should  then  be  covered  with  an  irritating  powder,  and 
the  pledgits  soaked  in  an  active  fluid :  one  may  safely  increase  the  doses 
of  a  medicine  which  has  been  long  employed.  Thus,  in  the  treatment 
of  the  venereal  disease  by  mercurials,  the  dose  is  to  be  gradually  in- 
creased ;  xvith  the  same  view,  Frederic  Hoffman  recommended  in  the 
treatment  of  chronic  diseases,  that  the  remedies  should  be  suspended  for 


*  This  is  so  beautifully  expressed  by  Dr.  Gregory,  that  we  cannot  resist  the  tempta- 
tion to  introduce  his  words: — [Godman.] 

tf  Voluptas  et  dolor  (ut  pulchra  Socratis  fabula  docet)  sorores  fuerunt,  utcunque  dis- 
similes,  diversamque  sortem  experts  ;  altera  ninrirum  optata  et  grata  omnibus,  altera 
pariter  invisa ;  quas  tamen  J  upiter  ita  sociavit  et  tarn  indissolubili  vinculo  conjunxit, 
tit  quamvis  natura  contrarias  et  diverse  spectantes,  quicunque  alterutram  complectitur, 
alteram  trahat  simul." 

•j-  In  some  very  rare  cases,  habit  produces  a  quit  contrary  effect.  Cullen  states,  that 
he  knew  persons  so  accustomed  to  excite  vomiting1  in  themselves,  that  the  twentieth 
part  of  a  grain  of  tartar  emetic  was  sufficient  to  exhe  a  convulsive  action  of  the  sto-- 
roach.-— Aiithor's  Note. 


41 

-a  time  and  then  resumed,  lest  the  system  should  get  accustomed  to 
them,  and  their  influence  be  lost.  The  same  motive  should  lead  one  to 
vary  the  treatment,  and  to  employ,  in  succession,  those  medicines  to 
which  nearly  the  same  qualities  are  assigned,  for, each  of  them  call  forth 
the  sensibility  in  a  peculiar  manner.  The  nervous  system  may  be  com- 
pared to  an  earth  abounding  in  various  juices,  and  for  a  full  display  of 
whose  fecundity,  it  is  necessary  that  the  husbandman  commit  to  it  the 
germs  of  various  plants. 

It  is  very  remarkable  that  habit,  or  the  frequent  repetition  of  the  same 
act,  which  uniformly,  under  all  circumstances,  and  in  all  organs,  blunts 
physical  sensibility,  should  improve  the  intellect,  and  increase  the  faci- 
lity, and  activity  of  execution  of  all  the  operations  of  the  understanding, 
or  of  the  actions  which  depend  on  them.  "  Habit  impairs  the  sensitive 
power,  and  improves  the  judgment"  Bichat  was  therefore  incorrect,  when 
in  his  distinction  of  the  organs  which  are  subservient  to  the  functions 
of  assimilation,  from  those  which  serve  to  keep  up  our  relation  with 
the  surrounding  objects:  he  maintained,  that  the  sensibility  of  the  latter 
becomes  more  exquisite,  while  the  sensibility  of  the  former  becomes  im- 
paired from  habit. 

But  can  a  painter,  because  he  judges  more  correctly  than  the  ignorant, 
of  the  beauties  of  a  picture,  be  said  to  see  it  better?  Surely  not,  for,  he 
may  with  a  sight  far  less  penetrating,  and  more  infirm,  form  a  more  ac- 
curate analysis,  from  the  habit  which  he  has  acquired,  and  judge  with  a 
great  deal  more  promptitude  and  certainty,  of  the  several  parts  of  the 
whole  ;  just  as  the  practised  ear  of  the  musician  seizes,  in  a  piece  of  mu- 
sic, and  during  the  most  rapid  execution,  the  expression  and  the  value  of 
all  the  notes  and  tones.  The  error  has  arisen,  from  its  being  forgotten, 
that,  correctly  speaking,  it  is  not  the  eyes  that  see,  or  the  ears  that  hear: 
that  the  impressions  produced  by  the  sounds  on  these  organs,  are  but  the 
occasional  cause  of  the  sensation,  or  of  the  perception  of  which  the  brain 
is  the  exclusive  seat.  Which  has  the  more  delicate  sense  of  hearing, 
the  North  American  savage,  who  hears  the  noise  of  the  step  of  his  ene- 
mies, at  distances  that  astonish  us,  or  the  artist  who  does  not  hear  a 
person  speaking  at  the  distance  of  fifty  paces  from  him,  but  who  directs 
with  judgment,  all  the  operations  of  a  great  orchestra,  and  who  distin- 
guishes skilfully,  the  effect  of  each  part  ? 

Bring  down  to  a  frugal  Pythagorean  regimen,  one  of  our  modem  epi- 
cures :  his  palate,  exhausted  of  its  sensibility  by  the  most  savoury  dishes, 
by  ardent  liquors,  and  the  most  exquisite  ragouts,  will  discover  no  taste 
in  dry  bread.  Let  him,  however,  live  on  bread,  if  he  can,  for  some  time, 
it  will  soon  appear  to  him  to  have  a  grateful  taste,  as  it  does  to  those  who 
make  it  their  principal  article  of  food,  or  who  take  it  only  with  substan- 
ces which  have  not  a  very  distinct  taste.  Although  with  the  sense  of 
smell,  that  of  taste  furnishes  us  only  with  ideas  the  most  directly  con- 
nected with  our  preservation,  those  which  most  turn  upon  the  wants  of 
our  animal  nature  :  although  we  retain,  with  difficulty,  the  impressions  of 
these  senses,  and  that,  to  enable  us  to  retain  them,  they  must  be  often  re- 
peated ;  the  epicure  has  so  carefully  analyzed  them,  that  he  has  attained 
to  the  discernment  of  the  faintest  differences  of  taste,  all  those  delicacies 
of  sensation,  which,  as  Montesquieu  says,  are  lost  to  us  vulgar  eaters. 

The  motions,  under  the  direction  of  the  will,  acquire  by  the  precision 
of  the  determinations,  the  same  aptness,  facility,  and  readiness,  and 
the  dancer,  who  surprises  us  with  his  agility,  hag  reflected,  more  than 

F 


42 

might  be  imagined,  on  the  very  complicated  steps  of  which  a  ballet  r* 
composed. 

Morbid  sensibility,  is  equally  under  the  influence  of  habit.  I  have  al- 
ways observed,  that  discharges  from  the  urethra  become  less  painful  from 
their  frequency.  There  is  nothing  down  to  disease  itself,  that  is  uotmade 
lighter  by  habit,  as  has  been  well  observed  by  Hippocrates. 

It  remains  then  demonstrated,  even  as  a  general  thesis,  that  habit,  or 
the  frequent  repetition  of  the  same  acts,  while  it  regularly  reduces  physi- 
cal sensibility,  improves  intelligence,  and  gives  facility  and  promptness  to 
all  the  motions  that  are  under  the  direction  of  the  will. 

§IX.    OF  THE  VITAL  PRINCIPLE*. 

The  words  -vital  principle,  vital  force,  See.  do  not  express  a  being  exist- 
ing by  itself,  and  independent  of  the  actions  by  which  it  is  manifested: 
it  must  be  used  only  as  an  abridged  formula,  which  serves  to  mark  the 
total  of  the  powers  that  animate  living  bodies,  and  distinguish  them 
from  inert  matter.  So  that,  whenever,  in  the  course  of  this  section,  I 
shall  use  these  terms,  or  any  equivalent,  it  is  to  be  taken  as  if  I  had  said, 
the  aggregate  of  the  properties  and  laws  that  regulate  the  animal  cecono- 
my.  This  explanation  is  become  indispensable,  now  that  several  wri- 
ters, realizing  a  mere  abstraction,  have  spoken  of  the  vital  principle, 
as  of  something  very  distinct  from  the  body,  as  of  a  being  altpgether  se- 
parable, which  they  have  invested  with  feeling,  and  thought,  and  even 
deliberate  intentions. 

From  the  remotest  antiquity,  the  many  and  striking  differences  of  liv- 
ing, and  inorganic  bodies,  have  led  some  philosophers  to  conceive  in  the 
former,  a  principle  of  particular  actions,  a  force  which  maintains  the  har- 
mony of  their  functions,  and  directs  them  all  to  a  common  end,  the  pre- 
servation of  individuals  and  of  the  species.  This  simple  and  luminous 
doctrine,  has  remained,  even  to  our  own  days,  only  modified  in  its  pas- 
sage through  many  years :  and,  no  one  now  disputes  the  existence  of  a 
principle  of  life,  which  subjects  the  beings,  that  enjoy  it,  to  a  system  of 
laws  different  from  those  which  inanimate  beings  obey  ;  a  force  which 
might  be  characterized,  as  withdrawing  the  bodies  it  animates,  from  the 
absolute  dominion  of  chemical  affinities,  which  would  else,  from  the 
multiplicity  of  their  elements,  oct  on  them  with  great  power ;  and  as 
maintaining  them  in  a  nearly  equal  temperature,  whatever  may  be  that 
of  the  atmosphere.  Its  essence  is  not  in  preserving  the  aggregation  of 
constituent  molecules,  but  in  drawing  to  it  other  molecules,  which,  by 
assimilation  to  the  organs  it  pervades,  replace  those  that  are  carried  off 
in  daily  waste,  and  serve  for  their  nourishment  and  growth. 

All  the  phenomena  that  are  to  be  observed  in  the  living  human  body, 
might  be  brought  as  proofs  of  the  principle  which  animates  it. — The 
actions  of  the  digestive  organs  on  its  food ;  the  absorption,  by  the  chy- 
lous  vessels,  of  its  nutritious  parts;  the  circulation  of  these  nutritious 
juices  through  the  sanguineous  system ;  the  changes  they  undergo  in 
their  passage  throughnhe  lungs,  and  the  secretary  glands;  the  impressi- 
bility by  outward  objects ;  the  power  of  approaching  or  avoiding  them; 
in  a  word,  all  the  functions  that  are  carried  on  throughout  the  animal 


See  APPENDIX,  Note  A. 


43 

oeconomy,  proclaim  its  existence.  But  it  is  customary  to  take  a  proof  of 
it  yet  more  direct,  from  the  properties  with  which  the  organs  of  these 
functions  are  endowed.  We  have  examined  these  properties,  and  we 
have  seen  that  each  of  them  presents  us  with,  at  least,  two  great  modifi- 
cations; that  the  last  discovers  three,  which  are,  voluntary  contractility, 
contractility  involuntary  and  insensible,  Stahl's  tonic  motion  ;  and 
lastly,  contractility  involuntary  and  sensible,  as  that  of  the  heart  and 
the  intestines. 

If  it  is  useful  to  analyse,  in  order  to  know,  it  is  of  equal  importance  not 
to  multiply  causes,  from  misconceiving  the  nature  of  effects;  and,  if, 
on  the  one  hand,  the  multitude  of  the  phenomena  of  life,  inclines  us  to 
the  belief  of  many  causes  to  produce  them;  the  unfailing  harmony  that 
pervades  all  the  actions,  their  mutual  connexions,  and  reciprocal  depen- 
dencies, point  much  more  decisively  to  a  sole  agent,  as  causing,  direct- 
ing, and  controuling  these  phenomena. 

The  hypothesis  of  the  vital  principle,  is  to  the  philosophy  of  living 
beings,  what  attraction  is  to  astronomy.  To  calculate  the  revolutions  of 
the  planets,  this  science  is  compelled  to  recognize  a  force,  which  draws 
them  constantly  towards  the  sun,  and  constrains  their  tendency  to  fly 
from  it,  within  the  measured  distance  of  those  ellipses,  which  they  de- 
scribe around  that  common  centre  of  light  and  heat,  which  dispenses  to 
them,  as  they  roll,  the  precious  germs  of  life  and  of  fertility.  We  are 
about  to  speak  of  this  force,  to  which  all  the  powers  that  animate  each 
separate  organ,  join  themselves,  and  in  which  all  the  vital  powers  are 
blended,  but  under  the  declaration,  for  the  second  time,  of  using  the  term 
only  in  a  metaphorical  sense.  Without  this  precaution,  I  might  lead  you 
into  all  the  false  reasonings,  which  those  have  fallen  into,  who  have  as- 
signed to  it  a  real  and  separate  existence. 

The  vital  power  is  in  perpetual  strife  with  the  powers  that  govern  in- 
animate bodies.  The  laws  of  individual  nature  are,  according  to  the  say- 
ing of  antiquity,  for  ever  struggling  against  those  of  universal  nature ; 
and  life,  which  is  only  this  contest  prolonged,  in  favour,  altogether,  of 
the  vital  powers,  during  health,  but  with  uncertain  issue  in  disease,  is  at 
an  end,  the  moment  in  which  the  bodies  endowed  with  it,  fall  again  into 
the  system  of  lifeless  being.  This  constant  opposition  of  vital  to  physi- 
cal laws,  both  mechanical  and  chemical,  does  not  withdraw,  altogether, 
living  bodies  from  the  controul  of  these  laws.  There  are  effects  always 
going  on  in  the  living  being,  chemical,  physical,  and  mechanical:  only 
these  effects  are  constantly  influenced,  modified,  and  altered  by  the  pow- 
ers of  life*. 

Why,  when  we  stand  up,  are  not  all  the  humours  carried  down  to  the 
lower  parts,  by  the  force  of  gravitation  ?  The  vital  power  resists  the  com- 
pletion of  this  hydrostatic  phenomenon,  and  neutralizes  this  tendency  of 
the  fluids,  the  more  successfully  as  the  individual  is  more  robust  and 
vigorous.  If  it  is  one  enfeebled  by  previous  disease,  the  propensity  will 
be  but  imperfectly  repressed:  the  feet,  after  a  certain  rime,  swell;  and 
this  oedematous  swelling  can  be  ascribed  only  to  the  insufficient  energy 
of  the  vital  powers,  which  determine  the  distribution  of  the  fluids,  &c. 

*  In  proof  of  this  may  be  adduced  the  observation  long-  since  made  by  Dr.  AIEXAJT- 
DER,  that  the  range  of  temperature  most  favourable  to  the  putrefaction  of  dead  animal 
matter,  being  between  86Q  and  100P  of  Fahrenheit,  includes  the  usual  standard  of  hu- 
man heat 


44 

When  a  tumbler  throws  himself  backwards,  the  blood  does  not  flow 
altogether  to  his  head,  though  this  is  become  the  lowest  part;  yet  the 
natural  tendency  of  fluids  downwards  is  not  altogether  overcome;  it  is 
only  diminished;  for  if  he  preserve  long  the  same  attitude,  the  struggle 
of  the  hydraulic  and  vital  powers  becomes  unequal:  the  former  prevail; 
they  accumulate  the  blood  upon  the  brain ;  and  the  man  dies. 

The  following  experiment  proves  incontestibly,  what  has  just  been  said 
of  the  power  of  resistance,  which,  in  the  human  body,  more  or  less,  effec- 
tually counterbalances  the  force  of  physical  laws.  I  applied  bags  filled 
with  very  hot  sand,  along  the  leg  and  foot  of  a  man  whose  artery  had 
been  tied  by  two  ligatures,  in  the  hollow  of  the  ham,  for  popliteal  aneu- 
rism. Not  only  the  limb  was  not  chilled,  which  is  what  happens  when 
the  course  of  the  blood  is  intercepted,  but  the  extremity  thus  covered, 
acquired  a  heat  much  above  the  ordinary  temperature  of  the  body.  The 
same  apparatus  applied  to  the  sound  leg,  did  not  produce  this  excess  of 
heat,  certainly,  because  the  fulness  of  life,  in  that  limb,  resisted  the 
physical  action. 

The  vital  principle  seems  to  act  with  the  greater  energy,  as  the  sphere 
of  its  activity  is  narrowed;  which  has  led  Pliny  to  say,  that  it  was 
chiefly  in  the  smallest  things  that  Nature  has  shown  the  fulness  of 
her  power*. 

The  circulation  is  quicker,  the  pulse  more  frequent,  the  determina- 
tions more  prompt,  in  men  of  short  stature.  Such  was  the  great  Alex- 
ander!;  never  did  man  of  colossal  make  display  great  activity  of  imagi- 
nation :  none  of  them  have  glowed  with  the  fire  of  genius.  Slow  in  their 
actions,  moderate  in  their  desires,  they  obey  without  murmuring  the  will 
that  governs  them,  and  seem  made  for  slavery.  Agrippa  (says  Omilius 
Probus,  in  his  History  of  Augustns)  advised  that  they  should  disband 
the  Spanish  guard,  and  that  in  its  room,  Caesar  should  choose  one  of 
German,  "  wotting  well,  that  in  these  large  bodies,  there  was  little  of 
"  coverte  malice,  and  yet  lesse  of  subtiltie,  and  that  it  was  a  people  more 
"  minded  to  be  ruled  than  to  rule." 

To  judge  soundly  of  the  remarkable  difference  which  inequality  of  sta- 
ture brings  into  the  character,  compare  extremes;  set  against  a  Colos- 
sus, a  little  man  of  diminutive  stature;  granting,  nevertheless,  to  this 
last,  full  and  vigorous  health.  You  may  guess  that  he  is  talkative,  stir- 
ring, always  in  action,  always  changing  his  place ;  one  would  say  that  he 
is  labouring  to  recover  in  time,  what  he  has  lost  in  space.  The  probable 
reason  of  this  difference  in  the  vital  activity,  following  the  difference  of 
stature,  arises  from  the  relative  bulk  of  the  primary  organs  of  life.  The 
heart,  the  viscera  of  digestion,  &c.  are  of  nearly  the  same  bulk  in  all 
men :  in  all,  the  great  cavities  are  nearly  of  the  same  extent,  and  it  is 
principally  in  the  length  of  the  lower  limbs  that  the  difference  of  stature 
will  be  found  to  lie.  It  is  easily  conceivable,  that  the  viscera  supplying 
the  same  quantity  of  nutritious  juices  to  a  smaller  bulk,  that  the  heart 
giving  the  same  impulse  to  blood  which  is  to  traverse  a  shorter  course, 
all  the  functions  will  be  executed  with  greater  rapidity  and  energy. 

By  an  obvious  consequence,  the  diseases  of  little  men  have  a  more 
acute  character;  they  are  more  vehement,  and  tend  more  rapidly  to  their 


*  Nusquam  magis  qiiam  in  minimis  est  Ma  JVatwa.     Hist.  Nat.  lib.  II.  cap.  2. 

f  Such  was  the  Greater  NAPOLEON ;  still  the  subsequent  assertions  are  too  gene- 
ral. We  have  not  forgotten  the  size  of  Dr.  JOHKSOJT,  and  mankind  will  never  forget, 
how  he  "  glowed  with  the  lire  of  genius." —  ' 


'  genius. " —  Gocbnan . 


45 

crisis*.  They  have  in  them  something  of  the  velocity,  I  wtfuld  even  say 
the  instability  of  morbid  re-action  during  infancy.  There  is  nothing 
even  to  the  duration  of  life,  on  which  the  differences  of  stature  have  not 
some  influence.  With  this  suspicion,  and  some  curiosity  to  ascertain 
its  justness,  I  hare  made  inquiries  in  the  hospitals,  when  people  in  ad- 
vanced life  are  taken  in,  and  I  found  them,  for  the  most  part,  occupied  by 
old  men  above  the  middle  size;  so  that  reasoning  and  observation  concur 
in  showing  that  all  things  else  being  equal,  those  of  superior  stature  have 
a  grounded  hope  of  prolonging  their  life  beyond  the  ordinary  term. 

I  have  observed  with  many  others,  that  the  whole  body  unfailingly  re- 
ceives an  increase  of  vigour,  from  the  amputation  of  a  limb.  Frequently, 
after  the  loss  of  a  part  of  the  body,  you  will  see  a  manifest  change  take 
place  in  the  temperament ;  those  that  were  weak,  even  before  the  disease 
which  brings  on  the  necessity  of  the  operation,  becoming  robust:  affec- 
tions, chronic  from  debility,  such  as  scrophula,  tabes  mesenterica,  dissi- 
pated $  glandular  swellings  resolved;  which  indicates  a  very  remarkable 
increase  in  the  actions  of  all  the  organsf. 

The  parts  most  remote  from  the  centre  of  circulation  are,  in  general, 
less  alive  than  those  which  are  nearer.  Wounds  of  the  legs  and  feet,  are 
more  liable  to  ulcerate,  because,  besides  the  circulation  of  the  fluids, 
which  the  slightest  weakness  greatly  retards  in  them,  their  life  is  too  fee- 
ble for  their  wounds  to  go  quickly  through  their  periods,  and  readily 
cicatrize.  The  toes  freeze  first,  when  we  remain  too  long  exposed  to 
severe  cold  ;  it  is  in  them  too  that  the  mortification  begins,  which  some- 
times attacks  a  limb  after  the  ligature  of  its  vessels. 

Thus,  although  we  may  say,  that  the  principle  of  life  is  not  seated  in 
any  part  of  our  being,  that  it  animates  every  system  of  organs,  every  se- 
parate organ,  every  living  molecule,  that  it  endows  them  with  different 
properties,  and  assigns  to  them,  in  some  sort  specific  characters,  it  must 
be  confessed,  thai  there  are  in  the  living  body  some  parts  more  alive, 
from  which  all  the  other?  seem  to  derive  motion  and  life.  We  have  al- 
ready seen  that  these  central  organs,  these  foci  of  vitality,  in  whose  life 
that  of  the  whole  body  is  involved,  diminish  gradually  in  number  in  the 
animal  kinds,  as  they  are  more  removed  from  man,  whilst  the  fewer  they 
are,  the  more  they  are  spread  out  over  the  body;  so  that  life  is  more  ge- 
nerally diffused,  and  its  phenomena  less  rigorously  and  strictly  connect- 
ed, as  we  descend  in  the  scale  of  being,  from  the  red  and  warm-blooded, 
to  the  red  and  cold-blooded  animals,  from  these  to  the  mollusca,  the 
Crustacea,  worms  and  insects,  to  the  polypus,  who  forms  the  extreme 
link  of  the  animal  chain,  and  lastly,  to  plants,  of  which  not  a  few,  like 

*  The  acute  diseases  of  tropical  countries,  especially  fever,  prove  more  fatal  to  short 
men,  or  those  of  middle  size,  than  to  the  tall, 

•j-  The  extraordinary  development  of  an  organ  never  takes  place  but  at  the  expense 
of  those  about  it,  of  which  it  draws  off  the  juices.  Aristotle  observes,  that  the  lower 
extremities  are  most  always  diy,  and  wasted  in  those  who  are  of  ardent  temperament, 
or  in  habits  of  frequent  venery.  Hippocrates  relates  in  his  work  (De  sere,  locis,  et  aguis, 
Foe's  :  fol.  293.)  that  the  Scythian  women  seared  their  right  breast,  that  the  arm  on 
that  side  might  grow  in  size  and  strength.  Galen  speaks  of  Athletes,  who,  in  his  time, 
kept  the  sexual  organs  in  the  most  entire  inaction,  that  withered,  shrunk,  and  perished, 
in  some  sort,  by  this  absolute  repose,  they  might  not  draw  off  the  nutritious  juices 
from  the  sole  nourishment  of  the  muscular  organs.  A  young  man,  who  several  times 
carried  off  the  prize  by  runinng  at  the  public  fetes,  abstained  from  venery  for  some 
months,  before  entering1  the  lists,  in  perfect  certainty  of  victorv.  after  this  privation. — 
Author'?  Mte. 


46 

the  zoophytes,  so  similar  to  them  in  many  respects,  are  endowed  with 
the  remarkable  property  of  reproduction  by  slips;  which  implies,  that 
each  part  contains  the  aggregate  of  organs  necessary  to  life,  and  can 
exist  alone. 

The  vital  principle  has  by  some  been  confounded  with  the  rational  soul; 
but  others  have  distinguished  it  from  that  emanation  of  divinity,  to  which, 
as  much  as  to  the  perfection  of  his  organization,  man  owes  his  superiori- 
ty to  all  the  animal  kinds.  What  bond  unites  the  material  principle, 
which  receives  impressions  and  transmits  them,  to  the  intelligence  which 
feels,  perceives,  examines,  compares,  judges,  and  reasons  on  them? 
Were  man  one,  says  Hippocrates,  did  his  material  principle  make  up  his 
whole  nature,  pleasure  and  pain  would  be  as  nothing  to  him :  he  would 
be  without  sensation :  for,  how  could  he  account  to  himself  for  impres- 
sions ?  Si  unus-  esset  homo,  non  doleret,  quiet  non  sciret  unde  doleret.  Here 
we  stand  on  the  confines  of  physiology  and  metaphysics;  let  us  beware 
of  setting  foot  in  the  dim  paths  that  are  before  us  :  the  torch  of  ob- 
servation would  yield  but  ineffectual  light,  too  faint  to  dispel  the  thick 
darkness  that  lies  over  them. 

The  vital  power  is  merely  the  vis  medicatrix  naturse,  more  powerful 
than  the  physician,  in  the  cure  of  many  diseases ;  the  art  of  the  physician 
consisting,  in  most  cases,  in  awakening  or  directing  the  action  of  that 
power.  When  a  thorn  is  thrust  into  a  part  endowed  with  sensibility,  a 
sharp  pain  is  felt,  the  fluids  rush  in  abundance  to  the  part,  it  becomes 
red  and  swollen;  all  the  vital  powers  are  excited,  the  sensibility  becomes 
more  acute,  the  contractility  greater,  and  the  temperature  rises.  Does 
not  this  increase  of  vital  energy  in  the  injured  part,  this  process  which 
takes  place,  around  the  substance  that  is  the  cause  of  the  disorder ;  those 
means  which  are  provided  to  expel  it,  indicate  the  existence  of  a  preserv- 
ing principle,  incessantly  watching  over  the  harmony  of  the  functions, 
and  struggling  against  all  the  powers  that  may  tend  to  interrupt  its  ex- 
ercise, or  to  annihilate  the  vital  motion? 

Ttieory  of  inflammation*.  Inflammation  may,  I  believe,  be  defined;  the 
increase  of  vital  properties  in  the  part  which  it  affects^.  Sensibility  becomes 
more  acute  in  the  part  so  affected,  its  contractility  greater;  and  from 
that  increase  of  sensibility  and  action,  arise  all  the  symptoms  character- 
istic of  inflammation.  Thus  the  pain,  the  swelling,  the  redness,  the  heat, 
and  the  difference  in  the  state  of  the  secretions,  denote  in  the  part  a  more 
energetic  and  active  vitality. 

Those  who  have  objected  to  the  definition  which  I  have  given  of  in- 
flammation, have  evidently  mistaken  the  functions  of  the  organs  for  their 
properties.  It  is  very  true,  that  inflammation  of  the  eye  is  attended  with 
loss  of  sight,  but  that  circumstance  depends  on  the  opacity  of  the  trans- 
parent parts  which  should  transmit  the  luminous  rays  to  the  retina.  The 
sight  is  prevented  by  a  mechanical  obstacle,  but  the  sensibility  of  the 


*  See  APPENDIX,  Note  G. 

t  IUFLAMMATIOX  is  a  state  of  disease.  A  wound  or  other  injury  is  inflicted,  the  nerves 
ana  vessels  are  injured,  and  sensibility  becomes  greater,  because  the  ability  to  resist,  or 
the  tone  of  the  part  is  lessened.  Hence  slighter  impressions  in  this  condition  produce 
pain.  The  swelling  is  owing  to  the  quantity  of  blood  received  into  the  vessels  being 
greater  than  in  health,  because  the  vessels  being  -weakened  are  distended :  the  redness  is 
produced  by  the  quantity  of  blood.  The  heat  is  accumulated,  because  the  natural  pro- 
cess, removing  its  excess  by  perspiration  is  suspended,  as  the  previous  injury  and 
consequences  check  this  secretion. — Gotlman. 


47 

organ  is  augmented  to  such  a  degree,  that  the  faintest  light  reaching  the 
bottom  of  the  eye,  through  the  transparent  cornea  dimmed  by  the  con- 
gestion of  the  vessels,  causes  in  it  intolerable  pain.  On  this  principle, 
darkness  is  universally  recommended  to  patients  affected  with  ophthal- 
mia. In  like  manner,  when  a  muscle  is  inflamed,  the  action  of  the  fibre, 
its  shortening,  is  prevented  by  the  congestion  in  the  cellular  membrane, 
which  covers  it  and  fills  its  interstices.  The  cause  preventing  contrac- 
tion, or  the  exercise  of  contractility,  is  mechanical,  and  maybe  compared 
to  that,  which,  in  an  inflamed  lung,  opposes  the  admission  of  air,  and 
the  passage  of  the  blood,  from  the  right  to  the.  left  side  of  the  heart. 
Can  any  one  call  in  question  the  increase  of  vital  action  in  peripneumony  ? 
I  am  therefore  of  opinion,  that  the  above  definition  is  better  than  that 
proposed  by  Bichat,  in  his  u  Anatomic  Generale,"  a  work  of  later  date 
than  the  first  edition  of  these  elements  of  physiology,  and  in  which  he 
makes  inflammation  to  consist  in  the  increase  of  those  vital  properties 
which  he  terms  insensible. 

All  the  parts  of  the  human  body,  with  the  exception  of  ths  epidermis 
and  its  different  productions,  as  the  nails  and  the  hair,  appear  capable  of 
inflammation.  One  might  include  among  these  "  epidermoid"  parts, 
certain  dry  and  slender  tendons,  as  those  of  the  flexors  of  the  fingers, 
which,  when  pricked,  lacerated  and  irritated  in  a  thousand  ways,  are  in- 
sensible to  pain,  and  remain  uninjured  in  the  midst  of  a  whitlow,  though 
attended  with  suppuration  of  all  the  neighbouring  soft  parts;  and  when 
exposed  to  the  air,  they  exfoliate  instead  of  granulating.  Organization  is 
so  indistinct  in  all  these  parts,  life  so  feeble  and  languid,  that  they  remain 
insensible  to  the  impression  of  all  those  causes  which  might  tend  to  in- 
crease its  activity. 

The  degree  of  sensibility  in  a  part,  the  number  and  size  of  the  nerves 
and  vessels  which  are  sent  into  it,  determine  the  degree  of  its  aptitude  to 
inflammation :  thus  the  bones  and  cartilages  inflame  with  considerable 
difficulty.  When  one  of  these  parts  is  laid  bare,  the  first  effect  of  the 
irritation  to  which  it  is  exjA*t,tci,  is  a  softening  of  its  substance.  When 
a  bone  is  laid  bare,  it  bpcor*i?«s  ^"'Jlag'rGus  uid  softens,  in  con:-;,  uacnce 
of  the  abt>oi^ticr,  of  the  phosphate  of  lime  which  fills  up  the  interstices  of 
its  tissue;  and  it  is  only  after  this  kind  of  incarnation,  that  fleshy  granu- 
lations begin  to  sprout,  as  may  be  observed  on  the  extremities  ot  bones 
after  amputation.  The  difficulty  w.ith  which  inflammation  is  set  up  in 
the  harder  parts  of  the  body,  explains  why,  before  the  twelfth  or  fifteenth 
day  after  a  fracture,  it  is  of  little  consequence  to  wards  union  of  the  bone, 
that  the  fractured  ends  should  be  placed  in  opposition  :  not  that  it  is  right 
to  wait  so  long,  before  applying  the  proper  bandages,  which  are  indis- 
pensable from  the  first,  to  prevent  the  pain  and  laceration  occasioned  by 
the  displaced  bone.  The  blood  is  determined,  from  all  quarters,  towards 
the  irritated  and  painful  part,  which  swells  and  assumes  a  red  colour, 
from  the  presence  of  that  fluid. 

The  swelling  would  be  unlimited,  if,  at  the  same  time  that  the  arteries 
increase  in  power  and  calibre,  to  occasion  that  determination,  the  veins 
and  lymphatics  did  not  acquire  a  corresponding  energy,  to  enable  them 
to  relieve  the  part,  of  the  fluids  which  have  accumulated  in  it,  and 
which  irritation  is  constantly  determining  to  it.  The  power  of  irrita- 
bility and  contractility  increases  with  sensibility;  the  circulation  is  more 
rapid  in  the  inflamed  part ;  the  pulsations  of  the  capillary  vessels  are  ma- 


48 

nifest.  The  part  is  likewise  hotter,  because,  in  a  given  time,  there  passes 
through  its  tissue  more  arterial  blood,  from  which  a  larger  quantity  of 
caloric  is  disengaged,  and  the  continued  effects  of  the  pulmonary  respira- 
tion are  better  marked  in  it  than  in  any  other  organ. 

It  forms  no  part  of  our  intention  to  treat  of  the  varieties  of  inflamma- 
tion :  they  depend  principally  on  the  structure  of  the  organ  which  is 
affected,  on  the  violence  and  rapidity  of  the  symptoms,  and  on  its 
effects. 

Is  not  the  turgescence  of  an  inflamed  part  occasioned  in  the  same  man- 
ner, as  in  parts  subject  to  erection,  as  the  corpora  cavernosa  of  the  penis 
and  of  the  clitoris,  the  nipples,  the  iris,  8cc.  ?  In  erection  of  the  penis,  as 
in  inflammation,  there  is  an  irritation,  a  determination  of  fluids  to  the 
part,  an  increase  of  sensibility  and  contractility;  yet  its  condition  is  not 
that  of  inflammation.  Nature  has  so  disposed  the  organization  of  these 
parts,  that  they  can  sustain,  without  injury,  those  instantaneous  augmen- 
tations of  vital  energy,  necessasy  to  the  exercise  of  the  functions  per- 
formed by  the  organs  to  which  they  belong.  As  in  inflammation,  these 
congestions  disappear,  when  the  cause  of  irritation  has  ceased  to  act; 
thus,  the  pupil  dilates,  because  the  iris  recedes,  when  the  eye  is  no  longer 
exposed  to  the  rays  of  a  vivid  light.  The  penis  returns  to  its  naturally 
flaccid  and  soft  state,  when  no  irritation  operates  to  determine  to  it  the 
fluids,  whose  presence,  as  loug  as  the  erection  lasts,  is  easily  explained 
by  the  continuance  of  the  irritation,  without  its  being  necessary  to  have 
recourse  to  mechanical  explanations,  to  account  for  that  phenomenon. 
When  the  irritation,  which  produces  the  vital  turgescence  of  the  penis 
or  iris,  is  tarried  too  far,  or  continues  too  long,  the  natural  congestion 
becomes  morbid.  It  is  well  known,  that  priapism  is  frequently  attended 
•with  mortification  of  the  penis,  and  that  the  too  long  continued  action  of 
light  on  the  eye,  brings  on  inflammation  of  that  organ. 

The  preceding  observations  on  inflammation  show,  that  an  acquaint- 
ance with  its  phenomena  is  useful,  even  in  a  physiological  point  of  view. 
The  vital  processes,  which  in  some  organs  take  place  in  so  obscure  a 
manner  that  they  are  imperceptible,  acquire  in  inflammation  a  character 
of  rapidity  and  intensity,  which  renders  it  much  easier  to  observe  and 
recognize  them.  Considered  in  a  general  and  abstract  point  of  view, 
and  merely  with  a  reference  to  its  object,  inflammation  may  be  consider- 
ed as  a  means  employed  by  nature,  to  repel  the  influence  of  noxious 
agents,  which,  when  introduced  within  the  body,  or  on  its  surface,  she 
has  no  power  of  resisting,  but  by  a  more  active  developement  of  the  pow- 
ers which  animate  it. 

During  the  severe  winter  of  1793,  the  chemist  Pelletier  repeated  the 
cekferated  experiment  of  freezing  mercury,  and  obtained  a  solid  ball  in 
the%alb  of  a  barometer,  which  he  had  for  along  while  kept  immersed  in 
the  midst  of  a  quantity  of  ice,  continually  moistened  with  nitric  acid. 
When  the  metal  had  attained  a  completely  solid  state,  he  drew  the  ball 
from  the  bulb,  and  placed  it  on  his  hand.  The  heat  of  the  parr,  joined  to 
that  of  the  atmosphere,  soon  restored  the  quicksilver  to  its  fluid  state :  at 
the  same  instant,  he  experienced  in  his  hand  so  intolerable  a  degree  of 
cold,  that  he  was  obliged  to  drop  the  quicksilver  instantly.  There  soon 
came  on,  in  the  painful  and  chilled  part,  a  phlegmonous  inflammation, 
which  was  cured  by  resolution.  Quicksilver,  in  a  solid  state,  is  one  of 
the  coldest  bodies  in  nature:  how  very  rapidly  the  caloric  must  have 


49 

been  carried  off  in  this  case,  and  how  deep  the  impression  must  have  been 
in  the  palm  of  the  hand,  doubly  affected  by  the  cold,  and  by  the  vital  re- 
action, which  terminated  in  inflammation  !  I  have  produced  a  similar  ef- 
fect, by  endeavouring  to  melt  a  piece  of  ice  in  my  hand,  during  the  heat 
of  summer.  In  this  experiment,  the  impression  of  cold  is  soon  succeed- 
ed by  a  sensation  of  acute  pain  and  extraordinary  thr.obbings,  in  the  hand 
and  fore  arm.  When  the  two  hands  are  afterwards  compared,  that 
which  held  the  piece  of  ice  is  extremely  red,  from  the  congestion  of 
blood  in  the  cutaneous  capillary  tissue,  and  is  very  different  in  its  appear- 
ance, from  that  which  was  not  the  subject  of  experiment. 

Analogous  facts,  if  seriously  considered,  should  induce  the  followers  of 
Brown  to  apply  to  the  effects  of  cold,  the  distinction  which  he  applied  to 
debility,  of  direct  and  indirect  They  would  have  no  difficulty  in  ascer- 
taining, that  in  its  medical  application,  that  negative  state  of  caloric, 
which  is  directly  debilitating,  may,  nevertheless,  by  the  re-action  which 
it  excites,  be  considered  as  an  indirect  tonic. 

§  X.    OF  THE  SYSTEM  OF  THE  GREAT  SYMPATHETIC 

NERVES*. 

The  great  sympathetic  nerves  are  to  be  considered  as  the  bond  destin- 
ed to  unite  the  organs  of  the  nutritive  functions,  by  whose  action  man 
grows,  is  evolved,  and  incessantly  repairs  the  continual  waste  attending 
the  vital  motions.  They  form  a  nervous  system,  very  distinct  from  the 
system  of  the  cerebral  nerves;  and,  as  the  latter  are  the  instruments  of 
the  functions  by  which  we  hold  intercourse  with  external  objects,  the 
great  sympathetic  nerves  supply  motion  and  life  to  the  organs  of  the  in- 
ward, assimilating,  or  nutritive  functions. 

In  animals,  without  vertebrae,  may  not  the  nervous  system,  which  floats 
in  the  great  cavities  with  the  viscera  which  they  contain,  be  considered 
as  consisting  entirely  of  the  great  sympathetics  ?  t  These  nsrves  are 
principally  distributed  to  the  organs  of  inward  life,  whose  activity,  in 
those  animals,  seems  to  grow,  in  proportion  as  their  external  senses,  and 
their  faculty  of  locomotion,  are  imperfect.  If  the  great  sympathies  exist 
in  all  the  animals  which  have  a  distinct  nervous  system,  do  they  not,  in 


*  See  APPENDIX,  Note  H. 

•j-  TREVIRANUS,  in  his  Biologie,  considers  the  knotted  cord  found  in  the  abdomen  of 
insects  and  worms  to  be  the  vertebral  ganglia  of  the  sympathetic  nerve.  That  it  can- 
not be  considered  a  spinal  cord  is  evident :  its  situation  sufficiently  shows  the  difference. 
The  mollusca,  and  many  animals  removed  a  little  above  this  class  in  the  scale  of  crea- 
tion, possess  merely  single  ganglia,  from  which  proceed  fibrillae  to  the  different  organs. 
The  great  sympathetic  nerve  is  "  the  most  general  and  the  most  original  of  all  the 
nerves."  Its  characters,  are,  however,  modified  in  different  classes.  "  In  worms  and 
insects  there  are  merely  vertebral  ganglia,  without  the  coeliac  ganglia  of  mammalia  and 
birds :  in  the  acephalous  mollusca  there  are  the  latter,  without  the  former ;  in  the  cut- 
tle-fish and  snails  there  are  single  ganglia  of  both  kinds. "  All  these  animals  have  no 
spinal  marrow ;  fishes  and  reptiles  have  one,  and  also  vertebral  ganglia,  but  the  cceliac 
is  not  fully  developed  in  them.  (See  the  Observations  of  SERRES  and  WEBEE)  as  in  birds 
and  mammalia. 

These  remarks  convey  the  sum  of  the  observations  made  by  those  who  have  inquired 
into  the  subject.  How,  therefore,  can  the  ganglial  class  of  nerves  be  considered  to  a* 
rise  from  the  cerebral  and  vertebral  masses  ?—  Copland. 

G 


50 

an  especial  manner,  contain  the  principle  of  vegetable  life,  essential  to 
the  existence  of  every  organized  body  possessing  the  power  of  diges- 
tion, absorption,  circulation,  secretion,  and  nutrition  ?  Finally,  is  it 
not  probable,  that  in  man,  the  system  of  the  great  sympathetic  nerves, 
has  a  great  share  in  occasioning  a  number  of  diseases,  and  that  the  im- 
pressions with  which  patients  are  affected,  arc  referred  to  their  nu- 
merous ganglions,  while  the  brain  is  exclusively  the  seat  of  intellect  and 
thought*  ? 

These  suggestions  will,  doubtless,  be  answered  in  the  affirmative,  if 
one  considers  the  origin,  the  distribution,  and  the  peculiar  structure  of 
these  nerves,  the  acute  sensibility  of  their  branches,  as  well  as  the  disor- 
ders attending  their  injury. 

Extended  along  the  vertebral  column,  from  the  base  of  the  skull  to  the 
lower  part  of  the  sacrum,  these  great  nerves,  in  some  measure  parasitic, 
do  not  arise  from  the  branches  supplied  them  by  the  fifth  and  sixth  pairs 
arising  from  each  side  of  the  brain;  they  live  and  are  nourished,  as  it 
were,  at  the  expense  of  all  the  nerves  of  the  spinal  marrow,  from  which 
they  receive  branches,  so  that  there  is  not  one  of  them,  from  which  one 
can  say,  that  the~*great  sympathetics  arise  exclusively.  The  numerous 
ganglions  which  are  distributed  along  their  course,  divide  them  into  so 
many  small  systems,  from  which  arise  the  nerves  of  the  organs  nearest  to 
them.  Amidst  these  bulgings,  considered  by  several  physiologists,  as  so 
many  little  brains,  in  which  is  performed  the  elaboration  of  the  fluid 
which  they  transmit  to  the  nerves,  no  one  is  of  more  importance  than  the 
semi-lunar  ganglion,  situate  behind  the  organs  which  occupy  the  epigas- 
tric region,  and  from  which  those  nerves  originate,  which  are  distribu- 
ted to  the  greater  part  of  the  viscera  of  the  abdomen  It  is  to  the 
region  occupied  by  that  ganglion,  in  which  the  great,  sympathetic  nerves 
unite,  and  which  may  be  considered  as  the  centre  of  the  system  formed 
by  their  union,  that  we  refer  all  our  agreeable  sensations;  there  it  is 
that  we  feel  in  sadness,  a  constriction  which  is  commonly  referred  to 
the  heart.  Thence,  in  the  sad  emotions  of  the  soul,  seem  to  originate 
those  painful  irradiations  which  trouble  and  disorder  the  exercise  of  all 
the  functions  f. 

The  numerous  filaments  of  the  great  sympathetic  nerves  are  finer,  they 
are  not  of  the  same  whitish  colour,  nor  of  the  same  consistence  as  the 
filaments  of  the  cerebral  nerves.  On  that  account,  they  are  less  easily 
dissected^,  the  nervous  fibrillae  are  less  distinct,  their  reddish  chords  are 


*  These  opinions  on  the  uses  of  the  great  sympathetic  nerves,  are  explained  in  my 
Essay  on  the  connexion  of  life  with  the  circulation.  This  essay  was  published  before 
any  thing1  that  has  appeared  on  the  same  subject. — Consult  the  .*'  Memoires  de  la  So- 
cie"te  Medicale  pour  1'an  VII." — Jl-uthor's  Note. 

f  Consult  on  the  subject  of  the  epigastric  centre,  Van  Helmont,  who  calls  it  the 
archeus  ;  Buftbn,  Bordeu,  Barthez,  and  Lacaze,  who  give  it  the  name  of  the  phrenic 
centre,  because  they  ascribe  to  the  diaphragm  what  belongs  to  the  nervous  ganglions 
placed  in  front  of  its  crura. — Author's  Note. 

t  One  of  the  best  modes  of  dissecting  them  is  to  macerate  the  part,  in  which  we  wish 
to  trace  their  ramifications,  during  two  or  three  days  in  water ;  then  place  it  for  a  short 
time  in  a  very  dilute  acid,  or  warm  spirits,  or  in  oil  of  turpentine.  The  filaments  of 
these  nerves  may  be  then  traced  more  distinctly.  Other  processes,  which  are  more 
complex,  are  requisite  to  the  dissection  of  the  minuter  ramifications,  especially  those 
which  supply  the  blood-vessels. —  Copland. 

Anatomists  are  perfectly  well  aware,  that  none  of  these  processes  are  to  be  relied 


51 

moister,  and  they  appear  formed  of  a  more  homogeneous  substance ; 
their  membranous  coverings  are  less  considerable.  They  are  likewise 
endowed  with  a  more  acute  and  more  delicate  sensibility.  Every  one 
knows  the  danger  attending  wounds  of  the  mesentery,  a  membranous  du- 
plicature,  in  itself  insensible,  but  containing  such  numerous  nerves  des- 
tined to  the  intestinal  tube,  that  the  most  pointed  instrument  can  scarcely 
wound  the  mesentery,  without  injuring  some  of  their  branches.  The 
pain  attending  affections  of  the  great  sympathetic  nerves,  is  of  a  peculiar 
kind;  it  leads  directly  to  the  extinction  of  the  vital  power.  It  is  a  well 
known  fact,  that  a  bruise  of  the  testicles  overpowers,  in  a  moment,  the 
strongest  man.  Every  one  knows  that  patients  who  die  of  a  strangulated 
hernia,  of  volvulus,  or  of  every  other  affection  of  the  same  kind,  die  in  the 
most  distressing  anguish,  their  heart  feels  oppressed,  and  they  are  tor- 
mented with  constant  vomiting.  Intestinal  and  nephritic  colics  are  at- 
tended with  the  same  sort  of  pain;  that  attending  injection  of  the  tunica 
vaginalis  in  hydrocele,  is  of  the  same  kind.  We  expect  a  favoura- 
ble event  of  the  operation,  only  in  those  cases  in  which  the  patient  has 
felt  pain  along  the  spermatic  chord,  in  the  course  of  the  spermatic  nerves, 
which  arise,  as  it  is  well  known,  from  the  renal  plexus.  In  the  case  of 
wounds  of  the  abdomen,  I  was  led,  by  the  nature  of  the  pain  which  the 
patients  suffered,  to  prognosticate  that  the  wounds  had  penetrated;  the 
event  justified  my  prognostic.  In  all  these  affections  of  the  great  sympa- 
thetic nerves,  the  pulse  is  frequent  and  hard,  the  face  is  covered  with  a 
cold  sweat,  the  features  are  sunk ;  all  the  symptoms  are  alarming,  and 
soon  terminate  fatally. 

The  use  of  the  system  of  the  great  sympathetic  nerves  is,  not  merely 
to  establish  a  closer  connexion  and  a  greater  union  between  all  the  or- 
gans which  perform  the  functions  of  assimilation,  but  likewise  to  free 
those  parts  from  the  influence  of  the  will.  A  power  of  the  mind  so  fickle 
and  so  varying,  that  life  would  be  in  constant  danger,  if  we  had  it  in  our 
power  to  stop  or  suspend  the  exercise  of  functions  with  which  life  is  es-, 
sentially  connected. 

If  we  consider  what  are  the  organs  to  which  the  functions  of  assimila- 
tion are  entrusted,  and  which  receive  their  nervous  influence  from  the 
great  sympathetic  nerves,  we  shall  find  that  the  action  of  the  greater 
number  is  wholly  independent  of  the  controul  of  the  will*.  The  heart, 
the  stomach,  the  intestinal  canal,  Sec.  do  not  obey  the  will,  and  seem  to 
possess  a  more  insulated  and  more  independent  existence,  and  act  and 
rest,  without  any  influence  on  our  part.  Some  of  these  organs,  as  the 
bladder,  the  rectum,  and  the  muscles  of  respiration,  which  do  not  receive 

upon  ;  and  they  also  know,  that  a  vast  number  of  nervous  filaments  exhibited  in  en- 
gravings, were  never  seen  elsewhere.  When  nervous  filaments  are  traced  until  they 
become  as  small  as  a  hair,  they  cannot  be  distinguished  from  cellular  substance — when 
coagulating  agents  are  used,  the  material  produces  corresponding  effects  on  all  the  ad- 
joining textures,  hence  the  difficulty  is  increased  rather  than  diminished.— Godman. 

*  All  these  parts  which  receive  their  nerves  from  ganglions,  are  equally  independent. 
Professor  Chaussier  thinks  that  the  upper  filaments  of  the  great  sympathetic  nerves 
ascend  along  the  internal  carotid,  and  join  the  sphenopalatine  and  lenticular  ganglions. 
M,  Ribes  thinks  he  has  ascertained  by  dissection,  that  several  very  long  and  slender 
filaments  follow  the  course  of  the  branches  of  the  internal  carotid,  and  like  them  are 
sent  to  the  base  of  the  brain,  beyond  which  they  cannot  be  traced.  I  have  myself  ob- 
served, in  dissection,  these  filaments  around  the  branches  of  the  internal  carotid  artery, 
but  I  had  always  considered  them  to  be  formed  of  cellular  substance.— Author's  Note. 


their  nerves  exclusively  from  the  great  sympathetics,  are  obedient  to  the 
will,  and  receive  from  the  brain  the  principle  of  motion,  the  former,  from 
the  branches  which  the  sacral  nerves  send  to  the  hypogastric  plexuses  : 
the  diaphragm,  from  the  nerves  which  it  receives  from  the  fifth  and  sixth 
cervical  pairs. 

The  great  sympathetic  nerves  supply  the  diaphragm,  the  rectum,  and 
bladder,  only  with  nerves  of  sensation.  This  provision  was  a  very  ne- 
cessary one,  for,  if,  as  is  the  case  with  the  heart,  and  the  intestines,  these 
parts  had  received  their  nerves  of  motion  from  the  great  sympathetics, 
their  action  would  have  been  independent  of  the  will,  as  is  the  case  with 
all  the  parts  which  these  nerves  supply  with  motion.  The  bladder  and 
rectum,  placed  at  the  extremities  of  the  digestive  apparatus,  and  destin- 
ed to  serve  as  reservoirs  to  the  excrementitious  residue  of  our  solid  and 
liquid  aliments,  would  have  been  constantly  evacuating  their  contents,  as 
fast  as  the  substances  which  are  destined  to  be  retained  within  them  for 
some  time,  reached  their  cavity. 

On  the  other  hand,  if  the  diaphragm  had  received  its  nerves  of  motion 
from  the  great  sympathetics,  respiration  would  have  ceased  to  be  a  vo- 
luntary function,  of  which  we  might  at  pleasure  accelerate,  slacken,  or 
even  completely  suspend  the  action.  To  prove  that  the  act  of  respira- 
tion is  under  the  controul  of  the  will,  we  may  have  recourse  to  analogy, 
and  adduce  the  instance  of  reptiles,  as  lizards,  frogs,  serpents,  salaman- 
ders, and  toads,  which  are  cold-blooded  animals,  and  in  which  this  func- 
tion is  manifestly  voluntary.  We  may  further  mention  those  slaves,  who, 
we  are  told  by  Galen,  put  themselves  to  death,  when  summoned  before 
their  executioners  or  judges.  According  to  thtet  physiologist,  and  others, 
they  choked  themselves  by  swallowing  their  tongue.  But  it  is  sufficient 
to  know  how  the  muscles  that  bind  down  the  tongue  are  situated,  and  the 
degree  of  motion  which  they  allow,  to  see  how  little  ground  there  is  for 
that  opinion.  The  action  of  the  brain  would,  in  that  case,  have  been  no 
lotiger  necessary  to  the  maintenance  of  life  ;  in  an  animal  without  a  brain, 
respiration  would  have  continued,  and  the  circulation  would  not  have 
been  interrupted.  The  death  of  that  viscus  would  not  have  been  attend- 
ed with  the  sudden  death  of  all  the  rest. 

The  nerves  which  arise  from  the  spinal  marrow,  and  which  give  to  the 
diaphragm  the  power  of  contraction,  a  power  which  that  muscle  loses 
suddenly,  if  these  nerves  be  tied,  appear  to  me  the  chief  links  which 
unite  the  internal  assimilating  or  nutritive  functions,  to  those  which 
keep  up  the  relation  of  the  animal  with  external  objects.  Without  this 
bond  of  union,  the  series  of  vital  phenomena  would  have  been  less  close, 
and  their  dependence  less  necessary.  Had  it  not  been  for  the  necessity 
that  the  diaphragm  should  receive  from  the  brain,  by  means  of  the  phre- 
nic nerves,  the  principle  which  determines  its  contractions,  acephalous 
animals,  which  are  born  without  that  organ,  might  continue  to  live  as 
they  did  before  birth,  when  the  organs  of  nutritive  life  received  blood, 
which  had  undergone,  in  the  lungs  of  the  mother,  the  changes  necessary 
to  life.  But  where  the  bond  which  united  them  to  the  mother  is  destroy- 
ed, obliged  themselves  to  produce  in  their  fluids,  the  necessary  changes, 
by  the  inhalation  of  the  vivifying  principle  contained  in  the  atmosphere, 
they  no  longer  can  obey  that  necessity;  the  organs  of  respiration  are  de- 
ficient in  the  principle  which  should  excite  them. 


53 

When  an  internal  inflammation  is  of  small  extent*,  and  is  seated  in  a 
part  in  which  there  are  not  many  nerves,  and  whose  tissue  yields  easily  to 
the  humours  which  irritation  determines  into  it,  the  whole  morbid  action 
takes  place  in  the  affected  part,  and  the  general  order  of  the  functions  is 
not  sensibly  deranged.  But  when  inflammation  takes  place  in  a  part  en- 
dowed with  much  sensibility,  or  of  a  close  texture,  as  the  fingers  and  toes, 
then  fever  comes  on,  because  a  sympathy  in  the  morbid  action  takes  place, 
between  the  diseased  part  and  the  rest  of  the  system.  The  diffusion  of 
the  local  action  almost  infalliby  takes  place,  when  inflammation  occurs  in 
one  of  the  organs  of  the  assimilating  functions.  This  effect  may  be  con- 
sidered as  uniform,  though  Morgagni  mentions  several  instances  of  in- 
flammation of  the  liver,  marked  by  no  peculiar  symptoms. 

A  knowledge  of  the  great  sympathetic  nerves  accounts  for  this  differ- 
ence. When  an  external  part  is  affected  with  inflammation,  the  irritation 
which  it  suffers,  is  by  means  of  its  nerves  propagated  to  the  brain,  which 
by  a  re-actionf;  called  by  Vicq-d'Azyr  (who  on  this  subject  has  only  de- 
veloped the  opinions  of  Vanhelmont)  internal  nervous  action,  transmits 
that  irritation  to  the  heart,  to  the  organs  of  respiration,  of  digestion,  and 
of  secretion,  in  which  the  phenomena,  denoting  a  febrile  state,  are  prin- 
cipally evolved.  When,  on  tiie  contrary,  the  heart,  the  lungs,  or  any 
other  internal  organ  is  affected  with  acute  inflammation,  all  the  viscera 
partake  in  the  derangement  with  which  any  one  of  them  is  affected,  and 
without  the  intervention  of  the  brain.  They  are  all  intimately  connected 
by  the  filaments  which  they  receive  from  the  great  sympathetic  nerves? 
and,  by  means  of  that. nervous  system,  which  is  in  an  especial  manner  ap- 
propriated to  them,  they  carry  on  a  more  intimate  intercourse  of  sensa- 
tions and  affections.  Besides,  the  derangement  of  the  important  functions 
entrusted  to  the  diseased  organs,  is  necessarily  attended  with  appropriate 
changes  in  all  the  acts  of  the  animal  csconomy,  in  the  same  manner,  no 
doubt,  as  the  defect  of  one  wheel  interrupts  or  disturbs  the  mechanism  of 
the  whole  machine:}:. 


*  A  thousand  pustules  in  the  small-pox  occasion  only  a  moderate  degree  of  fever,  if 
they  are  at  a  distance  from  each  other ;  but  if  the  disease  is  confluent,  that  is,  if  the 
pustules  are  close  together,  and  run  into  each  other,  the  fever  becomes  considerable,  and 
the  patient's  life  endangered.  The  fleshy  granulations  which  sprout  in  abundance  from 
an  ulcerated  surface,  are  so  many  small  phlegmons  unaccompanied  by  a  febrile  state, 
but  if  brought  close  to  each  other  by  irritation,  that  condition  will  not  fail  to  ensue. 
Vaccination  is  not,  in  the  greater  number  of  cases,  attended  by  the  slightest  febrile  ac- 
tion, if,  as  I  always  have  done,  the  punctures  are  made  at  a  certain  distance  from  each 
other,  so  that  the  inflammatory  areolse  may  not  run  into  each  other. — luthor's  Note. 

|  The  cerebral  re-action  appears  to  be  in  no  measure  necessary  to  the  induction  of 
symptomatic  fever :  it  may,  however,  contribute  to  its  continuance.  The  irritation  ap- 
pears to  be  propagated  to  the  heart  in  consequence  of  the  numerous  connexions  which 
this  organ  holds,  by  means  of  the  ganglial  nerves,,  with  the  other  viscera  ;  and  owing  to 
the  continuous  reticulation  of  these  nerves  upon  the  blood-vessels  from  the  heart  to  the 
capillary  terminations. — Copland. 

$  The  late  experiments,  performed  on  the  nervous  system  by  that  excellent  anatomist 
and  physiologist,  Charles  Bell,  have  kd  to  some  very  interesting  conclusions,  and  have 
thrown  much  light  on  a  very  obscure  subject.  He  arranges  the  nerves  in  the  following 
manner.  There  are  a  number  of  nerves  arising  from  the  spinal  marrow  by  double  roots, 
which  pass  out  laterally  to  the  regular  divisions  of  the  body,  never  taking  a  course  longi- 
tudinally. These  nerves  are  common  to  all  animals  from  the  worm  up  to  man,  and  are 
for  the  common  purposes  of  sensation  and  volition.  These  are  termed  regular  nei*vea; 
each  having  two  roots,  one  from  the  anterior  and  the  other  from  the  posterior  division 
of  the  medulla  spinalis.  The  5th  pair ;  suboccipital ;  seven  cervical ;  twelve  dorsal ; 
five  lumbar  and  six  sacral  constitute  thirty-two  (kuble,  perfect,  orregular  nerves.  The 


54 

There  exists  in  the  stomach  an  union  of  the  cerebral  and  sympathetic 
nerves,  which  explains  the  manifest  dependency,  in  which  that  one  of  the 
three  supports  of  life  is  found  with  the  brain;  a  dependency  so  marked, 
that  every  strong  affection  of  the  soul,  every  violent  agitation  of  the  mind, 
weakens  or  even  totally  suspends  the  action  of  digestion  in  the  stomach. 
This  combination  of  cerebral  and  sympathetic  nerves  likewise  accounts 
for  a  phenomenon,  which  was  mentioned  in  speaking  of  the  influence  of 
habit  on  the  action  of  the  organs.  The  stomach  differs  essentially  from 
the  intestinal  canal  j  for,  far  from  getting  accustomed  to  the  impression 
of  emetics,  so  as  to  become  by  degrees  less  sensible  to  their  action,  as  the 
intestines  to  the  action  of  purgatives,  though  three  grains  of  tartar  emetic 
could,  at  first,  scarcely  excite  it,  half  a  grain  only  of  that  salt  is  able  to 
bring  on  vomiting,  when  by  frequent  use,  it  has  acquired  the  habit  of  the 
motions  excited  by  its  action.  It  is  riot  in  that  case  with  the  stomach,  as 
with  a  limb,  whose  muscles  perform  motions  with  the  greater  ease  and 
facility,  when  they  have  been  often  practised. 

§  XI.    OF  THE  RELATIONS  OF  PHYSIOLOGY  TO  SEVERAL 
OTHER  SCIENCES. 

It  would  be  entertaining  a  very  incorrect  notion  of  the  science  of  liv- 
ing man,  to  imagine  with  some  authors,  that  it  solely  consists  in  the  ap- 
plication of  the  laws  of  Natural  Philosophy,  to  the  explanation  of  the 
phenomena  of  the  animal  ceconomy.  Physiology  is  an  independent  sci- 
ence; resting  upon  truths  of  its  own,  which  it  draws  from  the  observa- 
tion of  those  actions,  which,  in  their  aggregate  succession  and  connexion, 
constitute  life.  It  is  enriched,  it  is  true,  with  facts  furnished  to  it  by 
Natural  Philosophy,  Chemistry,  and  Mathematics  ;  but  what  it  has  bor- 
rowed from  these,  is  accessory  merely,  and  does  not  form  an  essential  part 
of  the  edifice  of  the  science.  Thus,  the  better  to  understand  the  mechan- 
ism of  hearing  and  vision,  physiology  borrows  from  acoustics  and  optics, 
elementary  notions  on  sound  and  light;  and,  in  order  to  obtain  a  more 
correct  knowledge  of  the  nature  of  our  solids  and  fluids,  and  of  the 
manner  in  which  animal  substances  are  constantly  passing  from  the  one 
to  the  other  of  these  two  conditions,  physiology  calls  in  the  aid  of  che- 
mistry. Thus,  geometry  and  mechanism  furnish  it  with  the  means  of 
better  understanding  the  advantageous  form  of  the  organs,  and  the  per- 
fection of  their  structure*. 


remaining  nerves  are  called  irregular.  They  have  a  single  fasciculus  or  root,  from 
one  column  of  the  spinal  marrow.  They  derive  their  name  from  the  irregularity 
of  their  ramifications,  and  their  want  of  symmetry ;  are  superadded  to  the  original  class 
and  correspond  to  the  number  and  complication  of  the  superadded  organs.  The  3d, 
4th  and  6th,  going  to  the  eye ;  the  7th  (portio  duru)  to  the  face  ;  the  9th  to  the  tongue  ; 
the  glossopharyngeal  to  the  pharynx ;  the  vagus  to  the  larynx,  lungs,  heart  and  sto- 
mach ;  the  phrenic  to  the  diaphragm  ;  the  spinal  accessory  to  the  muscles  of  the  shoul- 
der ;  and  the  external  respiratory  to  the  outside  of  the  chest,  are  the  irregular  or  super- 
added  nerves.  (See  Transactions  of  the  Royal  Society  for  1821 ;  British  Journal  of  Sci- 
ence, Jan.  1822 ;  the  first  number  of  Magendie's  Journal  of  Physiology ;  and  the  Phila- 
delphia Journal  of  Med.  and  Pliysl.  Science  for  August,  1893,  p.  240.)— Godroan. 

*  A  knowledge  of  mathematics,  and  of  the  whole  circle  of  natural  philosophy,  in- 
cluding more  especially  chemistry  and  natural  history,  and,  in  a  more  particular  manner, 
human  and  comparative  anatomy,  is  requisite  to  the  successful  study  of  physiology. 
This  branch  of  knowledge,  although  independent  of  some  of  these,  is  yet  more  easily 
acquired,  and  its  difficulties  are  better  explained,  by  a  previous  acquaintance  with  all  of 


35 

No  study  carries  along  v?ith  it  a  more  lively  interest,  than  that  of  the 
admirable  relations  existing  between  the  conformation  of  our  parts  and 
the  external  objects,  to  which  they  are  applied.  These  relations  are  cal- 
culated with  such  precision,  and  laid  down  with  such  accuracy,  that  the 
organs  of  sense  and  of  motion,  considered  in  this  point  of  view,  may  be 
regarded  as  the  model  of  the  most  ingenious  productions  of  art.  So  true 
it  is  in  the  words  of  the  great  physician  of  Pergamus,  that  nature  did 
every  thing  before  art,  and  better*. 

At  the  beginning  of  the  last  century,  geometrical  physicians,  deceived 
by  an  appearance  of  rigid  precision,  attempted  to  explain  every  thing  by 
the  calibre  of  vessels,  their  length,  their  curvatures,  the  compound  ratio 
of  the  action  of  solids  and  the  impulse  of  fluids.  Hence  were  formed  theo- 
ries so  very  imperfect,  that,  as  we  shall  see,  in  treating  of  several  points 
of  physiology,  and  especially  of  the  force  with  which  the  heart  acts,  not 
one  of  those  who  proposed  them,  coincides  with  those  who  have  since 
followed  their  track.  However,  it  does  not  admit  of  a  doubt,  that  there 
occur  in  the  animal  machine,  effects  which  are  referable  to  the  laws  of 
hydraulics.  The  brain,  for  example,  required  a  large  and  constant  sup- 
ply of  arterial  blood,  vivified  by  recent  circulation  through  the  lungs;  but 
the  too  rapid  and  abrupt  access  of  that  fluid  in  the  brain,  might  have  dis- 
ordered its  structure.  Nature,  therefore,  has,  as  we  shall  mention  in  the 
article  of  the  cerebral  circulation,  employed  all  the  hydraulic  resources 
in  her  power,  to  break  the  force  Avith  which  the  blood  enters  the  brain, 
and  to  slacken  its  course. 

Has  man  ever  applied  the  laws  of  hydraulics  in  a  more  felicitous  man- 
ner than  nature,  in  the  rete  mirable  formed  at  the  base  of  the  brain  by  the 
carotids  of  quadrupeds?  An  arrangement  truly  remarkable,  without  which, 
the  blood  conveyed  to  the  brain  by  those  arteries,  impelled  by  a  force  su- 
perior to  that  of  th*^  human  heart,  and  not  having  to  overome  the  resist- 
ance of  its  own  gravity,  would  infallibly  have  occasioned  a  disorganiza- 
tion of  that  organ,  whose  consistence  is  so  soft. 

As  to  the  application  which  is  allowable  of  mathematical  sciences,  it 
maybe  said,  that,  as  in  physiology,  but  little  is  absolutely  certainf,  and 
much  merely  probable,  we  can  reckon  only  on  probabilities,  and  seek  our 
elements  in  facts  deduced  from  observation  or  experience ;  facts  which 
when  collected  and  multiplied  to  a  certain  degree,  lead  to  results  of  equal 
value  with  truths  absolutely  demonstrated. 

The  phenomena  presented  by  living  bodies  vary  incessantly,  in  their 
activity,  their  intensity,  and  their  velocity.  How  can  mathematical  for- 
mulae apply  to  such  variable  elements?  As  well  might  you  inclose  in  a 
frail  vessel,  hermetically  sealed,  a  fluid  subject  to  expansion,  and  of  vari- 
able bulk.  The  motions  of  progression  in  man  and  in  the  animals,  afford, 


them.  Pathology  and  the  treatment  of  diseases,  also,  reflect  a  light  upon  physiology 
uhich  they  first  derived  from  this  productive  source. 

*  Quandoquidem  natura,  nt  arbitror,  et  prior  tempore  sit,  et  in  operibus  magis  sapiens 
qumnars.  GALENUS,  de  usu  partiwn,  lib.  VII.  cap.  13. 

It  was  from  observing  the  manner  in  which  nature  prevents  the  diffusion  of  light  in 
the  globe  of  the  eye,  that  Euler  was  led  to  the  improvement  of  his  astronomical  teles- 
cope  luthor's  Note. 

j  This  is  to  be  understood,  as  applying  only  to  the  causes  of  the  phenomena,  and  not 
to  the  phenomena  themselves;  for  physiology  is  perhaps  richer  than  any  other  science, 
in  facts  unquestionable,  and  easily  ascertained  by  observation. — Auih'ir\  -Vote. 


56 

nevertheless,  sufficient  correct  applications  of  calculation.  Calculation 
may  likewise  be  applied  with  advantage,  to  the  measurement  of  the  re- 
sults of  our  different  secretions  to  ascertain  the  quantity  of  air,  or  of  ali- 
ment, introduced  into  our  organs,  Sec. 

Among;  the  principal  causes  which  have  retarded,  in  a  considerable  de< 
gree,  the  progress  of  physiology,  may  be  enumerated  the  mistake  of  those 
who  have  endeavoured  to  explain  all  the  phenomena  of  living  bodies,  by 
a  single  science,  as  chemistry,  hydraulics,  Sec.  while  the  union  of  all  these 
sciences,  will  not  account  for  the  sum  of  these  phenomena.  The  abuse, 
however,  of  these  sciences,  should  not  be  a  reason  for  setting  them  aside 
altogether.  The  facts  obtained  from  natural  philosophy,  chemistry,  me- 
chanics, and  geometry,  are  so  many  means  applicable  to  the  solution  of 
the  great  problem  of  the  vital  ceconomy;  a  solution  which,  though  as  yet 
undiscovered,  should  not  be  considered  as  unattainable,  and  to  which  we 
shall  approach  the  nearer,  as  we  attempt  it  with  a  greater  number  of  da- 
ta. But  it  cannot  be  too  often  repeated,  that  he  alone  can  hope  for  that 
honour,  who,  in  the  application  of  the  laws  of  natural  philosophy  to  liv- 
ing bodies,  will  take  into  account  the  powers  inherent  in  organized  na- 
ture, wnich  controul,  with  supreme  influence,  all  the  acts  of  life,  and  mo- 
dify the  results  that  appear  most  to  depend  on  the  laws  by  which  inor- 
ganic bodies  are  governed. 

Anatomy  and  physiology  are  united  by  such  close  relations,  that  it  has 
been  an  opinion  with  some,  that  they  are  absolutely  inseparable.  If  phy- 
siology, say  they,  has  for  its  object,  a  knowledge  of  the  functions  carried 
on  by  our  organs,  how  is  one  to  understand  their  mechanism,  without 
knowing  the  instruments  by  which  they  are  performed?  One  might  as 
well  attempt  to  explain  the  manner  in  which  the  hand  of  a  watch  performs 
the  circle  of  its  diurnal  revolution,  without  understanding  the  springs 
and  numerous  wheels  which  set  it  in  motion.  Haller  is  the  first  who  es- 
tablished the  connexion  between  anatomy  and  physiology,  and  who  illus- 
trated it  in  his  great  work.  Since  Haller,  a  great  number  of  anatomists, 
and  among  them  Soemmering*,  in  a  work  recently  published,  have  com- 
bined, as  much  as  possible,  these  two  sciences  ;  the  latter,  in  treating  se- 
parately of  each  system  of  organs,  explains  what  is  best  known  of  their 
uses  and  properties. 

However  close  the  connexion  between  anatomy  and  physiology,  they 
have,  nevertheless,  appeared  perfectly  distinct  to  the  greater  number  of 
authors,  and  we  have  several  valuable  works  on  anatomy,  of  which  phy- 
siology occupies  but  a  small  part. — This  manner  of  embracing  the  two 
sciences  appears  to  me  attended  with  the  greatest  advantage;  in  fact,  if 
the  insulated  description  of  organs  suffices  to  the  physiologist  who  wishes 
to  study  their  functions,  that  method  is  attended  with  the  disadvantage  of 
furnishing  few  truly  useful  views,  in  the  practice  of  operative  surgery. 
To  render  the  knowledge  of  the  human  body  more  especially  applicable 
to  the  practice  of  surgery,  it  is  necessary,  not  only  to  consider  separately 
the  different  parts,  but  likewise  to  view  them  in  their  connexion,  and  to 
determine  precisely  their  relations.  The  anatomist,  who  knows  that  the 
principal  artery  of  the  thigh  is  the  crural, — that,  continued  under  the 

*  J.  Ch.  Soemmering,  de  carports  humani  fabrica,  6  vols.  8vo.  1S04. 

This  work  possesses  a  great  deal  of  merit ;  independent  of  its  anatomical  correctness,, 
the  author  has  throughout  adhered  to  the  best  rules  of  logic,  and  analyses  the  human 
structure  with  great  clearness  and  force. — Godman. 


57 

name  of  popliteal,  it  passes  behind  the  knee  in  its  way  to  the  leg*— 
that,  in  its  course,  it  supplies  with  branches  different  parts  of  the  limb — 
even  though  he  knew  perfectly  the  name,  the  number  of  these  branches, 
the  varieties  to  which  they  are  subject,  the  parts  to  which  they  are  dis- 
tributed, would  nevertheless  possess  a  knowledge  of  that  branch  of  the 
system,  almost  useless  in  the  treatment  of  the  diseases  with  which  it  may 
be  affected.  The  situation  of  the  artery,  its  direction,  the  parts  which 
surround  it,  its  precise  relations  to  each  of  them,  its  superficial  or  deep 
seated  course,  &c.  are  the  only  circumstances  from  which  he  can  derive 
auy  advantage. 

He  who,  in  this  point  of  view,  cultivates  anatomy,  may  be  compared  to 
the  chemist;  in  the  same  manner  as  the  latter  is  never  better  acquainted 
with  a  substance,  than  when  he  is  able  to  decompose  it,  and  to  reproduce 
it  from  a  combination  of  its  parts,  so  the  anatomist  is  well  acquainted 
with  the  body  of  man,  only,  when  having  studied  separately,  and  with  the 
greatest  care,  each  of  his  organs  and  each  of  the  systems,  formed  by  the 
collection  of  a  certain  number  of  similar  organs,  he  is  able  to  assign  to 
each  of  them  its  place,  to  determine  its  relations,  and  the  proportions 
which  it  bears  in  the  structure  of  anyone  of  our  limbs.  The  study  of  the  lat- 
ter is  much  more  difficult  and  extensive  than  that  of  the  former;  for,  the 
chemist  who  decomposes  and  recompounds  a  well-known  substance, 
phosphate  of  lime,  for  instance,  attains  only  to  the  knowledge  of  its  con- 
stituent principles,  and  respective  proportions?  the  phenomena  of  situa- 
tion altogether  escape  him.  The  anatomist,  on  the  other  hand,  who  knows 
rtiat  such  apart  is  composed  of  bones,  of  muscles,  of  nerves,  of  vessels, 
must  know,  not  only  every  one  of  these  parts,  their  relative  bulk,  but  the 
exact  place  in  which  they  are  to  be  found. 

Anatomy,  pursued  in  this  spirit,  offers  a  field  of  wide  extent :  it  is  the 
art  which  Leibnitz  called  the  analysis  of  situation,  analysis  situs  ;  and  the 
knowledge  of  it  is  too  important  not  to  require  a  separate  place  among 
the  departments  of  medical  knowledge.  I  will  not  pass  over  the  motives 
that  are  alleged  for  combining  anatomy  and  physiology  in  one  course  of 
instruction.  Anatomy,  confined  to  the  mere  description  of  the  organs,  is 
too  dry  and  fatiguing ;  physiology  throws  over  it  interest  and  variety; 
it  helps  to  ensure  the  attention  of  the  hearers,  who  will  retain  more  per- 
manently, what  they  have  listened  to  with  pleasure.  Would  not  one  think 
that  physiological  details  were,  for  an  audience,  what  is  contrived  for  a 
sick  and  froward  child,  in  the  honey  that  is  rubbed  on  the  edge  of  the  cup, 
to  disguise  the  bitterness  of  the  draught  that  is  to  recall  him  to  life  ?  In 
combining  two  objects,  of  which  one  has  no  interest  but  that  of  useful- 
ness, whilst  the  other  is  engaging  as  well,  the  attention  will  be  not  merely 
divided,  but  altogether  distracted,  and  the  mind  of  those  who  read  or  lis- 
ten, will  skim  over  dry  details,  to  seize  with  avidity  what  furnishes  more 
to  its  activity  of  intelligence.  Anatomy  is  to  physiology  what  geography 
is  to  history.  General  considerations  on  the  situation,  the  size,  the  form, 
the  relations,  the  structure  of  the  organ,  are  an  indispensable  preparation 
to  the  perfect  understanding  of  its  functions  :  accordingly,  you  shall  find 
much  anatomy  in  physiological  treatises,  as  you  find  much  geographical 
detail  in  faithful  historians. 

I  have  said  enough,  I  trust,  to  escape  the  reproach  of  not  having  filled 
my  book  with  anatomical  descriptions,  from  the  multitude  of  excellent 
works  we  possess  on  the  anatomy  of  the  human  body.  Let  us  now  inquire 
what  relation  physiology  bears  to  Comparative  Anatomy. 

H 


58 

If  a  machine  can  be  perfectly  known,  only  alter  taking  it  to  pieces? 
down  to  its  simplest  elements  ;  if  the  mechanism  of  the  whole  action  is 
conceived,  only  by  separately  studying  the  action  of  each  different  part, 
Comparative  Anatomy,  by  aid  of  which  we  can  study,  in  the  great  chain 
which  the  animal  kinds  compose,  the  separate  action  of  each  organ,  ap- 
preciate its  absolute  or  relative  importance,  consider  it,  at  first,  insulated 
and  reduced,  so  to  speak,  to  its  own  powers,  in  order  to  determine  what 
part  it  bears  in  the  carrying  on  of  a  function ;  Comparative  Anatomy 
is  of  absolute  necessity  to  him  who  would  make  great  progress  in  the 
knowledge  of  man ;  it  may  be  looked  upon  as  a  sort  of  analytic  me- 
thod, by  means  of  which  we  more  completely  attain  to  the  knowledge  of 
ourselves. 

In  order  to  conceive  rightly  the  operations  of  the  human  intellect,  and 
explain  the  generation  of  the  faculties  of  the  soul,  metaphysicians  have 
imagined  a  statue,  into  which  they  have  infused  a  gradual  animation,  by 
investing  it,  one  by  one,  with  our  organs  of  sensation.  Now,  Nature  has 
realized  in  some  sort  this  dream  of  philosophy.  There  are  animals  to 
which  she  has  entirely  denied  the  organs  of  sight  and  hearing;  in  some, 
taste  and  smell  seem  to  have  no  separate  existence  from  touch  5  in  others, 
she  has  exercised  a  sort  of  analysis  on  a  system  of  parts  which  all  concur 
in  one  function.  It  is  thus,  that  in  some  animals,  divesting  the  organ  of 
hearing  of  the  accessories  allotted  to  collect,  transmit,  and  modify  the 
rays  of  sound,  she  has  reduced  it  to  a  simple  cavity,  filled  with  a  gelati- 
nous fluid,  in  which  float  the  extremities  of  the  acoustic  nerve,  alone  fit- 
ted to  reeeive  the  impression  of  sound  ;  a  fact  which  overthrows  all  the 
hypotheses  that  had  ascribed  this  sensation  to  other  parts  of  the  auditory 
apparatus. 

Of  all  the  physical  sciences,  Comparative  Anatomy  is  that  which  fur- 
nishes the  most  useful  facts  to  physiology.  Like  physiology,  it  is  concerned 
with  organized  living  beings :  there  is,  therefore,  no  need  of  watching 
against  the  false  applications,  so  often  made  from  the  sciences,  whose  ob- 
jects are  matter  inorganic  and  dead,  or  which  study,  in  living  beings  only 
the  general  properties  of  matter.  Haller  was  so  well  aware  of  the  utility 
of  introducing  this  science  into  physiology,  that  he  has  brought  together 
the  greater  part  of  the  facts  known  in  his  time,  on  the  anatomy  of  ani- 
mals, at  the  head  of  each  chapter  of  his  immortal  work. 

This  general  consideration  of  living  and  animated  beings,  so  well  adapt- 
ed to  unveiling  the  secret  of  our  organization,  has  this  further  advantage, 
that  it  enlarges  the  sphere  of  ideas  of  him  who  applies  to  it.  Let  him  who 
aspires  to  that  largeness  of  conception,  so  requisite  in  medicine,  where 
facts  are  so  multiplied  and  various,  explanations  so  contradictory,  and 
rules  of  conduct  so  unfixed,  cast  a  general  glance  on  this  great  division 
of  organized  beings,  of  which  many,  in  their  physical  structure,  so  nearly 
resemble  man  : — he  will  see  the  sovereign  Architect  of  the  world  distri- 
buting to  all,  the  element  of  life  and  activity,  giving  to  some  a  less  pow- 
er of  motion,  to  others  more  j  so  that,  formed  all  on  one  model,  they 
seem  only  the  infinitely  varied,  but  gradual  shades  of  the  same  form,  if 
forms  have  shades  like  colours;  never  passing  abruptly  from  one  to  ano- 
ther, but  rising  or  falling  by  gentle  and  due  degrees;  covering  the  inter- 
val that  separates  two  different  beings,  with  many  species  that  serve  as 
a  transition*  from  one  to  the  other,  and  which  present  a  continuous  series 


*  The  conception  is  noble  and  interesting  of  a  scale  of  being1,  which,  as  was  said  by 
C,  Bonnet,  connecting  all  the  worlds,  embracing  all  the  spheres,  should  extend  from 


59 

of  advancement  or  degradation ;  organization  being  constantly  simplified, 
In  descending  from  man  to  the  inferior  creatures ;  but  rising  In  complex- 
ity, in  re  ascending  from  those  animals  to  man,  who  is  the  most  complex 
being  in  nature,  and  was  justly  considered,  by  ancient  philosophy,  as  the 
master-piece  of  the  Creator. 

If  the  intimate  structure  of  our  organs  totally  eludes  our  investigation, 
it  is,  that  the  finest  and  most  delicate  of  their  constituent  parts  are  of  such 
minute  dimensions,  that  our  senses  have  no  hold  on  them.  It  is  then 
well  to  have  recourse  to  analogy,  and  to  study  the  organization  of  ani- 
mals that  exhibit  the  same  organs  on  a  larger  scale.  Thus,  the  cellular 
texture  of  the  lungs,  which  cannot  be  distinctly  shown  in  man,  on  account 
of  the  extreme  minuteness  of  the  smallest  bronchise,  may  be  satisfactorily 
seen  in  the  vesicular  lungs  of  salamanders  and  frogs.  In  like  manner,  the 
scales  which  cover  the  bodies  of  fishes  and  reptiles,  or  the  legs  of 
birds,  give  us  a  just  idea  of  the  structure  of  the  epidermis,  and  of  the 
arrangement  of  its  small  scales,  which  lie  over  each  other,  in  a  part  of 
their  surface. 

The  human  structure  being  more  complicated,  must  produce  effects 
more  numerous,  and  results  more  varied,  and  more  difficult  to  under- 
stand. In  commencing  the  study  of  the  animal  organization  by  that  of 
man,  we  do  not  therefore,  follow  the  analytic  method,  we  do  not  proceed 
from  what  is  simple,  to  what  is  more  complex.  It  would  perhaps  be  an 
easier  and  a  more  natural  way  of  arriving  at  a  solution  of  the  grand  and 
difficult  problem  of  the  animal  oeconomy,  to  begin  by  explaining  its  most 
simple  terms;  to  rise  by  degrees  from  plants  to  vegetating  animals,  as 
polypi;  from  these  to  white-blooded  animals,  then  to  fishes  and  reptiles; 
from  the  latter  to  warm-blooded  animals,  and  lastly,  to  man  himself, 
placed  at  the  head  of  that  long  series  of  beings  whose  existence  becomes 
complicated,  in  proportion  as  they  approach  him. 

The  study  of  every  part  of  natural  history,  and  especially  of  Compara- 
tive Anatomy,  cannot  fail,  therefore,  to  prove  of  infinite  advantage  to  the 
physiologist;  a  truth  well  expressed  by  the  eloquent  M.  de  Buffon*,  who 
says,  that  if  there  existed  no  animals,  the  nature  of  man  would  be  still 
more  incomprehensible. 

I  shall  say  nothing  of  the  well-known  relations  of  physiology  to  medical 
science,  of  which  it  is  justly  considered  as  the  base  or  support.  Medi- 
cine, called  by  some  the  art  of  healing,  by  others  more  properly,  the  art 
of  treating  diseases,  may  be  defined  the  art  of  preserving  health  of  curing 


the  atom  to  the  most  exalted  of  cherubim.  Without  carrying  it  so  high  or  so  low,  if 
\ve  confine  it  to  the  natural  beings  with  which  we  are  well  acquainted,  and  which  can 
be  brought  under  observation,  it  will  be  seen,  that  the  idea  is  not  so  chimerical  as  some 
writers  of  most  respectable  authority  have  supposed  it.  The  plan  traced  by  C.  Bonet  is 
evidently  defective ;  we  find  in  it  beings  set  beside  each  otlrer,  that  have  but  faint  lines 
of  resemblance,  or  altogether  illusive.  The  present  state  of  the  natural  sciences  would 
allow  of  its  being  better  done :  one  might  try  at  least  for  all  bodies  what  Jussieu  has 
executed  with  regard  to  vegetable  productions ;  and  if  this  undertaking,  in  the  hands  of 
men  the  most  able  to  bring  it  to  a  successful  termination,  left  any  thing  defective,  would 
not  that  imperfection  be  an  indication  of  the  existence  of  other  worlds,  or  of  lands  yet 
unknown  on  the  globe  ws  inha*bit ;  undiscovered  regions  where  those  animals,  and 
plants  and  minerals  would  be  fo%nd  which  were  wanting  to  fill  up  the  gaps  in  the  im- 
mense series  of  co- ordinate  existence.  Demonstratum  fuit  et  hoc,  nullam  rent  contraries, 
vel  omnino  multum  differentes,  quaUtates  recipere  posse,  nisi  per  media  prius  iter  fecerit.— 
GALENUS  de  usu  partium,  lib  iv.  cap.  12. — Author's  Note. 

*  Histoire  Nat  torn.  V.  12mo.  p.  241.    Discours  sur  la  nature  des  anitnaux. 


60 

diseases,  or  of  rendering  them  more  supportable;  medicine,  in  ail  its 
parts,  is  enlightened  by  physiology,  and  cannot  have  a  surer  guide.  Ow- 
ing to  a  neglect  of  this  auspicious  guide,  therapeutics  and  materia  medica 
long  remained  involved  in  a  mist  of  conjectures  and  hypotheses.  Physi- 
cians should  never  for  a  moment  forget,  that  as'a  great  number*  of  dis- 
eases consist  in  a  derangement  oi  the  vital  function,  all  their  efforts 
should  tend  to  bring  back  sensibility  and  contractility  to  their  natural  con- 
dition :  that  the  best  classification  of  diseases  and  of  medicines,  is  that 
which  is  founded  on  a  judicious  distinction  of  the  vital  powers.  With 
this  view  it  is  that  M.  Alibert,  in  his  elements  of  materia  medica,  classes 
medicines  according  to  their  effects  on  sensibility  or  contractility,  and 
according  to  the  organs  on  which  their  action  is  particularly  exerted. 

§  XII.    CLASSIFICATION  OF  THE  VITAL  FUNCTIONS. 

After  having  treated  separately  of  the  vital  powers  or  faculties,  nothing 
is  easier  than  to  arrange,  in  a  clear  and  methodical  order,  the  functions 
carried  on  by  the  organs  which  these  powers  call  into  action.  The  term 
function^  might  be  defined,  means  of  existence.  This  definition  would  be  the 
more  just  as  life  is  only  the  exercise  of  these  functions,  and  as  in  cases, 
when  any  one  of  the  more  important  can  no  longer  be  carried  on.  From 
not  distinguishing  the  faculties  from  the  functions  which  are  merely  the 
acts  of  faculties  or  powers,  several  modern  divisions,  though  far  prefera- 
ble to  the  old  classification  of  the  functions  into  vital,  animal,  and  natural, 
are,  nevertheless,  deficient  in  accuracy  and  simplicity.  Thus  Vicq-d'Azyr, 
in  the  classification  of  the  phenomena  of  physiology  inserted  in  the  dis- 
course which  he  has  prefixed  to  his  work  on  anatomy,  mistakes  the 
cause  for  the  effect,  and  places  sensibility  and  irritability  among  the 
functions,  and  commits  another  mistake,  by  ranking  among  the  latter,  os- 
sification, which  is  but  apeculiar  mode  of  nutrition,  belonging  to  parts  of 
a  hard  structure. 

The  best  method  of  classing  the  actions  which  are  performed  in 
the  living  human  body  is  doubtless,  that  by  which  they  are  distributed 
and  arranged  according  to  the  object  which  they  fulfil.  Aristotle,  Buf- 
fon,  and  especially  Grimaud,  have  laid  on  that  base  the  foundation  of  a 
method  which  we  shall  adopt,  with  the  modifications  which  we  are  about 
to  mention. 

Aristotle  and  Buffon  had  observed,  that  among  the  acts  of  the  living 
oeconomy,  some  were  common  to  all  beings  that  have  life,  to  plants  and 
animals  during  sleep  and  in  waking,  while  others  seemed  to  belong  ex- 
clusively to  man,  and  to  the  animals  which  more  or  less  resemble  him. 
Of  these  two  modes  of  existence,  the  one  vegetative,  the  other  animal, 
the  former  appeared  to  them  the  more  essential,  as  being  more  diffused, 

*  All  diseases  consist  in  physical  derangements,  as  solutions  of  continuity,  displace- 
ments, organic  alterations,  as  polypi,  aneurisms,  and  other  affections  resulting  from  or- 
ganic affection  and  alteration  of  structure  ;  vital  lesions,  as  fevers,  ataxite,  adynamise, 
vesanise,  &c.  see  Nosographie  Chirnrgicale. — Jluthor's^'ote. 

f  The  function  of  any  part,  is  the  office  or  duty  it  fulfills,  or  the  end  for  which  it  is 
designed.  The  function  of  the  lachrymal  gland  is  to  secrete  tears: — of  the  ducts,  to 
convey  them  to  the  nose,  &c.  Life  must  exist  anterior  to  the  performance  of  function, 
although  the  correct  discharge  of  the  latter  is  necessary  to  the  continuance  of  the  former. 
The  definition,  as  applied  to  the  term  function,  is  incorrect—when  it  refers  to  the  re- 
sults produced  by  function,  it  is  unexceptionable. — Godman. 


61 

and  consisting  merely  in  assimilation  of  nutritive  molecules,  in  the  nutri- 
tion absolutely  necessary  to  the  preservation  of  the  living  being*,  who,  as 
his  substance  is  incessantly  wasting-,  would  soon  cease  to  exist,  if  these 
continual  losses  were  not  always  repaired  by  the  act  of  nutrition. 

Grimaud,  Professor  of  Physiology  at  Montpellier,  too  soon  lost  to  the 
science  which  he  cultivated  as  a  philosopher,  truly  deserving  that  name, 
adopted  this  simple  and  luminous  division,  developed  it  better  than  had 
been  done  before  him,  and  uniformly  followed  in  his  lectures  and  in  his 
worksf.  This  division  of  the  functions  into  internal,  which  he  likewise 
calls  digestive,  and  into  external  or  loco-motive,  lately  brought  forward 
under  the  name  of  organic  and  animal,  the  former  of  which  terms  is  quite 
inaccurate  and  defective,  since  it  leads  to  a  belief,  that  the  animal  life,  or 
of  relation  is  not  confined  to  organs,  and  that  their  vital  instruments  are 
solely  employed  on  internal  life  or  of  nutrition  (Motus  assimilationis,  Bacon  ; 
Bias  alterativum,  VanhelmoLt.)  This  distinction  does  not  comprehend 
the  whole  of  the  phenomena,  and  does  not  embrace  the  sum  of  the  func- 
tions which  are  performed  in  the  animal  ceconomy.  In  fact,  there  are 
not  found  in  the  two  great  classes  which  it  establishes,  the  acts  by  which 
animals  and  vegetables  reproduce  and  perpetuate  themselves,  and  immor- 
talize the  duration  of  their  species.  All  the  functions  destined  to  the  pre- 
servation of  the  species  are  not  included  5  they  merely  relate  to  the  func- 
tions subservient  to  the  preservation  of  individuals. 

I  have,  therefore,  thought  it  right  to  include  under  two  general  classes, 
in  the  first  place,  the  functions  which  belong  to  the  preservation  of  the 
species,  functions  without  which  man  might  exist,  as  we  see  in  eunuchs, 
but  without  which  the  human  species  would  soon  perish,  from  a  loss 
of  the  power  of  reproduction.  In  laying  down  these  two  great  divi- 
sions, I  have  merely  considered  the  object  and  end  which  each  function 
has  to  fulfil. 

Among  the  functions  which  are  employed  in  the  preservation  of  the 
individual,  some  fulfil  this  office  by  assimilating  to  his  own  Substance 
the  food  with  which  he  is  nourished ;  the  others,  by  establishing,  in 
a  manner  suited  to  his  existence,  his  relations  with  the  beings  which  sur- 
round him. 

The  functions  destined  to  the  preservation  of  the  species,  may  likewise 
be  divided  into  two  classes.  Those  of  the  first  class  require  the  concourse 
of  two  sexes;  they  constitute  generation,  properly  so  called;  those  of  the 
second  order,  exclusively  belong  to  the  female,  who,  after  conception,  is 


*  Namanima  nutritiva  etiam  aliis  inest,  etprima  et  maxima,  commums  facuUas  animse, 
secundum  quam  omnibus  vivere  inest  AIUSTOT.  de  anim,  lib.  ii.  cap.  4. 

|  Ir>  his  MS.  lectures  on  physiology,  he  seems  to  feel  a  complacency  in  that  division 
which  he  had  in  a  manner  appropriated  to  himself,  by  his  happy  illustrations  of  it,  and 
by  the  changes  which  he  had  introduced  into  it.  In  every  lecture,  I  might  almost  say 
in  every  page,  he  returns  to  this  division,  explains  it,  dilates,  and  comments  upon  it. 
«  The  functions,"  says  he,  "  may  be  divided  into  two  great  classes ;  some  are  formed  in 
the  interior  of  the  body,  and  exclusively  belong1  to  it ;  others  take  place  outwardly,  and 
belong  to  external  objects,"  &c.  The  digestive  power  presides,  in  his  opinion,  over 
the  internal  fw-ctions,\\hose  object  is  nutrition:  the  loco-motive  power  directs  the  ex- 
ternal functions.  "  ft  is  by  means  of  the  organs  of  sense  that  the  animal  enlarges 
his  existence,  that  he  applies  and  distributes  it  on  the  surrounding  objects,  that  he  takes 
cognizance  of  the  qualities  in  those  objects  which  concern  him  ;  it  is  by  means  of  the 
muscles  essentially  obedient  to  the  organs  of  sense,  that  lie  adapts  himself  to  those  ob- 
jects, that  he  places  himself  in  a  manner  suited  to  the  mode  of  tbeir  activity,"  &c. — 
Jluthor's  Note. 


alone  destined  to  bear,  to  nourish,  to  bring  into  the  world,  and  suckle  the 
new  being,  the  result  of  conception*. 

The  internal,  assimilating,  or  nutritive  functions  concur  in  the  same 
end,  and  all  serve  to  the  elaboration  of  the  nutritive  matter.  The  aliment 
once  admitted  into  the  body,  is  subjected  to  the  action  of  the  digestive  or- 
gans, which  separate  its  nutritive  parts ;  the  absorbents  take  it  up,  and 
convey  it  into  the  mass  of  fluids;  the  circulatory  system  conveys  it  to  all 
the  parts  of  the  body,  makes  it  flow  towards  the  organs;  the  lungs  and 
the  secretory  glands  supply  it  with  certain  elements,  and  deprive  it  of 
others,  alter,  modify,  and  animalize  it;  in  fine,  nutrition,  which  may  be 
considered  as  the  complement  of  assimilating  functions,  whose  object  it 
is  to  provide  for  the  maintenance  and  growth  of  the  organs,  applies  to 
them  this  animalized  substance,  assimilated  by  successive  acts,  when  it  has 
become  quite  similar  to  them. 

Several,  however,  of  these  functions,  serve  at  once  to  preserve  and  to 
destroy.  Absorption,  which  takes  up  extraneous  molecules  to  be  em- 
ployed in  the  growth  of  the  organs,  takes  up  equally  the  organic  mole- 
cules which  are  detached  by  motion,  friction,  heat,  and  all  the  other  phy- 
sical, chemical,  and  vital  causes.  The  action  of  the  heart  and  of  the 
blood-vessels  sends  these  fragments,  together  with  the  parts  truly  recre- 
mentitious,  towards  the  lungs,  which,  at  the  same  time  that  they  bring 
about  a  combination  of  the  nutritive  parts  with  the  oxygen  of  the  atmos- 
phere, separate  from  the  blood  the  materials  which  can  no  longer  be  em- 
ployed in  nourishing  the  organs;  the  same  power  sends  them  towards  the 
secretory  glands,  which  not  only  purify  what  is  liquid,  by  separating  from 
it  that  which  cannot  without  danger  remain  in  the  animal  ceconomy,  but 
which  likewise  elaborate  or  prepare  peculiar  fluids,  some  of  which  are 
results  of  the  act  of  nutrition,  are  employed  in  that  act,  and  impart  to  the 
substances  on  which  it  is  performed  a  certain  degree  of  animalization, 
(as  to  the  bile  and  saliva)  while  the  others  seem  to  be  intermediate  states, 
which  the  nutritive,  particles  of  the  food  are  obliged  to  undergo,  before 
the  complete  animalization  5  such  are  the  serous  fluids  and  the  fat. 

It  might  perhaps  seem  more  in  conformity  to  the  order  of  nature,  to 
have  combined  the  account  of  respiration  with  that  of  the  circulation  by 
treating  of  the  course  of  the  venous  blood,  after  the  action  of  the  absorb- 
ent vessels,  with  which  the  veins  have  so  much  analogy. — Then  to  have 
treated  of  the  phenomena  of  respiration,  or  of  the  conversion  of  the  ve- 
nous blood  into  arterial,  and  of  the  course  of  the  latter  into  all  the  parts 
of  the  body,  by  the  action  of  the  heart  and  arteries;  but,  the  advantage 
which  would  be  obtained  from  a  method  so  contrary  to  the  common  prac- 
tice, which  is  to  consider  separately  the  functions  of  circulation  and  res- 
piration, appeared  to  me  too  unimportant  to  justify  its  adoption. 

The  external  or  relative  functions  equally  connected  by  their  common 
destination,  connect  the  individual  to  every  thing  that  surrounds  him; 
the  sensations,  by  warning  him  of  the  presence  of  objects  which  may  be 


*  The  classification  of  the  functions  which  RICHF.RAND  adopted,  with  a  slight  modifi- 
cation from  GRJMAUD,  nearly  agrees  with  the  one  more  generally  followed  by  the  best 
modern  physiologists.  SPREXOKL  arranges  them  into  the  vegetative,  the  sensiferous,  and 
the  generative.  MAGESIUE  divides  them  into  functions  of  relation,  functions  of  nutrition, 
and  functions  of  generation.  LENHOSSEK,  professor  of  anatomy  and  physiology  in  the 

classes  the  functions  into  those  of 


university  of  Vienna,  the  latest  writer  on  physiology,  classe 
organic  life,  of  aenvfermis  or  animal  life,  and  those  belonging 


g  {.Q  generation- — Copland. 


useful  or  injurious  to  him ;  motion,  by  enabling  him  to  approach,  or 
avoid  such  objects,  according;  as  he  perceives  relations  of  advantage  or 
disadvantage,  according  as  the  opposite  sensations  of  pain  or  pleasure  re- 
sult from  his  action  on  them,  or  from  theirs  on  him.  In  fine,  voice  and 
speech  give  him  communication  with  beings  enjoying  the  same  means  of 
communication,  and  that  without  a  necessity  of  motion.  The  brain  is  the 
principal  organ  of  these  functions,  as  thesystem  of  circulation  is  the  cen- 
tre of  the  assimilating  functions.  All  the  impressions  received  by  the 
organs  of  sense  are  transmitted  to  the  brain,  and  from  the  brain,  determi- 
nations arise,  as  well  as  the  voluntary  motions  and  the  voice.  The  san- 
guineous system  receives  the  molecules  destined  to  nutrition,  and  those 
which  are  to  be  thrown  out  of  the  body.  The  sensitive  and  circulatory 
systems  are  the  only  systems  provided  with  a  centre,  (the  brain  and  the 
heart)  which  extend  to  all  parts  of  the  body,  by  emanations  originating 
from  that  organ,  or  terminating  in  it  (the  nerves,  the  arteries,  and  veins,): 
and,  as  the  motions  and  the  voice  depend  on  sensation,  and  are  immedi- 
ately connected  with  it  as  necessary  consequences,  so,  respiration,  secre- 
tion, and  nutrition,  are,  in  a  manner,  but  consequences  of  the  circulation 
which  distributes  the  blood  to  all  the  organs,  in  order  that  these  may 
produce  on  it  various  changes  which  constitute  respiration.,  secretion  and 
nutrition.  They  are,  to  anticipate  what  is  to  come  hereafter,  only  differ- 
ent kinds  of  secretion  that  take  place  at  the  expense  of  the  different  prin- 
ciples contained  in  the  blood. 

The  circulation  which  holds  the  functions  of  nutrition  in  a  kind  of  de- 
pendence, subjects  the  brain,  which  is  the  principal  organ  of  the  external 
functions,  to  an  influence  still  more  immediate  and  indispensable.  The 
muscular  motions  are  not  less  under  its  influence.  It  is  the  first  function 
that  is  apparent  in  the  embryo,  whose  evolution  it  brings  about;  in  natu- 
ral death,  of  all  the  functions,  it  is  the  last  to  cease.  There  are  many 
reasons  which  justify  Haller,  for  having  placed  it  in  the  first  order,  and 
for  having  begun  by  its  history,  his  great  work  on  physiology.  I  enter 
into  this  digression,  only  to  expose  the  absurdity  of  the  claims  of  some 
authors,  who,  because  they  have  varied  the  methodical  order  of  the  func- 
tions, broken  the  series,  or  made  the  slightest  changes  for  example,  by 
placing  the  history  of  the  function  of  smell  and  taste  before  the  account 
of  the  internal  or  nutritive  functions,  think  they  have  totally  changed  the 
aspect  of  the  science:  pitiful  sophists,  who  accumulate  subleties  instead 
of  facts  and  ideas. 

In  warm  and  red-blooded  animals,  the  nutritive  functions,  digestion, 
absorption,  circulation,  respiration,  the  secretions  and  digestion  are  per- 
formed as  in  man,  and  in  that  respect  there  exist  between  them  very 
slight  differences;  nay,  in  some  animals,  these  functions  are  performed 
with  much  more  energy. — Thus  several  animals  digest  substances,  on 
which  our  own  organs  produce  no  effect,  and  others  (birds)  have  a  more 
rapid  circulation,  a  more  active  nutrition,  and  evolve  more  heat.  But  not 
one  of  them  is  as  well  provided  with  organs  to  keep  up  intercourse,  as  a 
living  being,  with  the  surrounding  objects.  In  no  one  animal,  are  the 
senses  possessed  of  the  same  degree  of  perfection  ;  the  eagle,  whose  sight 
is  so  piercing,  has  a  very  dull  sense  of  touch,  taste,  and  smell.  The  dog, 
whose  smell  is  exquisite,  has  a  very  ordinary  extent  of  sight:  in  him,  the 
the  taste  and  touch  are  equally  imperfect. — His  touch,  in  the  perfection 
of  which  no  animal  comes  up  to  man,  has  not  been  improved  in  delicacy 
at  the  expense  of  the  other  senses.  The  sight,  the  hearing,  the  taste, 


64 

aud  smell,  preserve  a  great  delicacy,  when  their  sensibility  has  not  been 
impaired  by  injudicious  qr  too  frequent  impressions.  The  sensitive  cen- 
tre is  in  no  one  better  developed,  and  fitter  to  direct  safely  the  use  of  the 
organs  of  motion.  No  other  animal  can  articulate  vocal  sounds,  so  as  to 
acquire  speech. 

This  greaier  extension  of  life  in  man,  from  the  number  and  perfection 
of  his  organs,  makes  him  liable  to  many  more  diseases  than  the  other 
animals.  It  is  with  the  human  body,  as  with  those  machines  which  be- 
come more  liable  to  be  deranged,  by  increasing  the  number  of  their  wheels, 
with  a  view  of  obtaining  more  extensive  or  more  varied  effects. 

All  organized  bodies  are  possessed  of  assimilating  functions ;  but  as 
assimilation  requires  means  varying  in  number  and  power,  according  to 
the  nature  of  the  being  which  performs  it,  the  series  of  assimilating  phe- 
nomena commences  in  the  plant  by  absorption,  since  it  draws  immediate- 
ly from  the  earth,  the  juices  which  it  is  to  appropriate  to  itself.  Its  ab- 
sorbing system,  at  the  same  time,  performs  the  functions  of  a  circulatory 
organ,  or  rather,  the  circulation  does  not  exist  in  plants,  and  the  direct 
and  progressive  motion  of  the  sap  which  ascends  from  the  root  towards 
the  branches,  and  sometimes  in  a  retrograde  course,  from  the  branches, 
towards  the  'roots,  cannot  be  compared  to  the  circulation  of  the  fluids 
which  takes  place  in. man,  and  in  the  animals  which  most  resemble  him, 
by  means  of  a  system  of  vessels  which  every  moment  bring  back  the  flu- 
ids to  the  same  spot,  and  convey  them  over  the  whole  body,  by  making 
them  describe  a  complete  circle,  frequently,  even,  a  double  rotation  (ani- 
mals with  a  single  or  double  circulation,  that  is,  whose  heart  has  one  or 
tv/o  ventricles.)  Plants  breathe  after  their  own  manner,  and  produce  a 
change  in  the  atmospherical  air.  by  depriving  it  of  its  carbonic  acid  gas, 
the  result  of  combustion  and  of  animal  respiration,  so  that  by  a  truly  ad- 
mirable reciprocity,  plants,  which  decompose  carbonic  acid,  and  allow 
oxygen  to  exhale,  continually  purify  the  air,  which  combustion  and  animal 
respiration  are  incessantly  contaminating*. 

The  functions  preservative  of  the  species  are  common  to  animals  and 
plants.  The  organs  by  which  these  functions  are  performed,  when  com- 
pared in  these  two  kingdoms  of  nature,  offer  a  resemblance  which  has 
struck  all  naturalists,  and  has  led  them  to  observe,  that  of  ail  these  acts 
of  vegetable  life,  no  one  is  more  analogous  to  the  animal  oeconomy,  than 
that  by  which  fecundatio'n  is  effected. 

*  This  opinion  originated  with  PHIESTLEY,  and  was  generally  adopted,  in  opposition 
to  the  experience  of  his  cotemporary,  the  celebrated  SCHEELE.  Subsequent  physiolo- 
gists, especially  ELLIS,  GILBT,  and  T.  DE  SAUSSURE,  have  shown,  by  well  conducted  ex- 
periments, that  all  plants,  whether  growing-  in  absolute  darkness,  in  the  shade,  or  when 
not  exposed  to  the  direct  rays  of  the  sun,  "  are  constantly  removing  a  quantity  of  oxygen 
from  the  atmosphere,  and  substituting-  an  equal  volume  of  carbonic  acid."  Thus  far 
these  philosophers  nearly  agree.  They  differ,  however,  very  widely  respecting  the 
manner  in  which  this  change  is  effected.  ELLIS  supposes  that  the 'leaves,  flowers, 
fruits,  stems,  and  roots  of  plants,  emit  carbonaceous  matter,  which  combines  with  the 
oxygen  of  the  surrounding  air.  GILBT  and  SAUSSUHE  are  of  opinion,  that  the  oxygen  is 
absorbed  by  the  respiratory  organs,  and  that  the  carbonic  acid  is  formed  within  the 
plant. 

Although  vegetables,  under  the  ordinary  circumstances  of  their  growth,  consume  oxy- 
gen during  respiration,  and  disengage  carbonic  acid,  yet,  according  as  their  situation  and 
particular  condition  may  require,  they  partially  absorb  the  carbonic  acid  from  the  air, 
convert  it  to  their  use,  decompose  it,  and  emit  the  oxygen  which  results  from  the  de- 
composition, especially  when  they  are  exposed  to  the  sun's  rays.  The  illustration  of 
this  subject  belongs  to  vegetable  physiology. — Copland, 


65 

We  shall  not  here  explain  the  general  characters  of  the  two  orders  of 
functions  which  are  subservient  to  the  preservation  of  the  species :  the 
differences  which  belong  to  them  are  pointed  out  in  several  parts  of  this 
work*.  I  shall  merely  observe  with  the  authors  who  have  considered 
them  generally,  that  they  are  in  an  inverse  ratio  to  each  other,  so  that,  in 
proportion  as  the  activity  of  the  assimilating  functions  increases,  that  of 
the  external  functions  is  abated.  Grimaud  has,  in  the  most  complete 
manner,  illustrated  this  idea  of  the  constant  opposition  which  exists  be- 
tween those  two  series  of  actions,  over  which,  in  the  opinion  of  that  phy- 
sician, there  preside  two  powers  which  he  calls  loco-motive  and  diges- 
tive. It  is  in  no  kind  of  animals  more  distinct  than  in  the  carnivorous, 
which  possess  organs  of  sense  of  the  greatest  delicacy,  together  with 
muscles  capable  of  prodigious  efforts,  and  yet  powers  of  assimilation  so 
feeble  that  their  food  cannot  be  digested,  unless  it  be  composed  of  mate- 
rials analogous  in  composition  to  their  own  organsf. 

Too  much  importance  should  not  be  attached  to  this  classification  like 
all  other  divisions,  it  is  purely  hypothetical.  All  is  connected  together, 
all  is  co-ordinate  in  the  animal  oeconomy ;  the  functions  are  linked  toge- 
ther, and  depend  on  one  another,  and  are  performed  simultaneously;  all 
represent  a  circle  of  which  it  is  not  possible  to  mark  the  beginning  or  the 
end.  In  circulum  abeunt  (Hippocrates.)  In  man,  while  awake,  digestion, 
absorption,  circulation,  respiration,  secretion,  nutrition,  sensation,  mo- 
tion, voice,  and  even  generation  may  be  performed  at  the  same  time ;  but, 
whoever  in  the  study  of  the  animal  oeconomy  should  bestow  his  attention 
on  this  simultaneous  exertion  of  the  functions,  would  acquire  but  a  very 
confused  knowledge  of  themj. 

By  becoming  familiar  with  these  abstractions,  one  might  soon  mistake 
them  for  realities;  one  might  even  go  the  length  of  seeing  two  distinct 
lives  in  the  same  individual ;  one  would  be  apt  to  assign  as  the  character 
of  internal  life,  that  it  is  carried  on  by  organs  independent  of  the  will.— 
Althongh  this  faculty  of  the  soul  presides  over  the  phenomena  of  respi- 
ration, of  mastication,  of  the  expulsion  of  the  urine  and  faeces,  one  might 
consider  life  as  intrusted  to  unsymmetrical  organs,  although  the  heart,  the 
lungs,  and  the  kidneys,  are  evidently  symmetrical;  one  might  fancy  it  to 

*  Especially  in  the  account  of  living  beings,  §  V.  of  the  Preliminary  Discourse ;  arti- 
cles sleep  said  fetus.  It  is  impossible  at  present  to  go  over  all  these  distinctions,  without 
entering  into  useless  and  disagreeable  repetitions. — Authors  Note. 

f  In  carnivorous  animals,  the  power  of  digestion  is  exceedingly  weak ;  but  their  mus- 
cles are  very  powerful.  This  relative  force  of  the  muscles  was  necessary  in  carnivorous 
animals;  as  they  live  by  depredations  and  slaughter,  as  their  instinct,  'in  unison  with 
their  organization,  sets  them  constantly  at  war  with  every  thing  that  has  life,  and  as  their 
subsistence  depends  on  their  being  victorious  in  the  battles  to  which  Nature  incessantly 
calls  them.  GmMAun/r^  jlfemoir  on  Nutrition  — Author's  Note. 

t  The  division  which  I  lay  down,  is  not  to  be  strictly  adopted,  and  as  being  absolutely 
true.  It  is  a  mere  hypothesis  to  be  attended  to,  only  in  so  far  as  it  assists  in  arranging 
one's  ideas  in  a  more  orderly  manner.  For,  every  arrangement,  even  when  arbitrary, 
is  useful  in  laying  before  us  a  great  number  of  ideas,  and  in  thereby  facilitating  the  com- 
parison that  is  to  be  instituted  among  them.  All  the  acts  of  Nature  are  so  connected, 
and  are  linked  together  in  so  close  an  union,  and  she  passes  from  the  one  to  the  other, 
by  such  uniform  motions,  and  by  gradations  so  insensible  and  so  adjusted,  as  to  leave 
no  space  rbr  us  to  lay  down  the  lines  of  separation,  or  demarcation,  which  we  may 
choose  to  draw.  All  our  methods  of  classing  and  arranging  the  productions  of  Nature, 
are  mere  abstractions  of  the  mind,  which  does  not  consider  things  as  they  really  are, 
but  which  attends  to  certain  qualities,  and  neglects  or  rejects  all  the  rest. 
Lectures  on  Plntsiol*:?". — Jluthr>ryfs  Note. 


66 

exist  in  the  foetus,  which  neither  breathes,  nor  digests',  £c.  Nothing  in 
the  animal  oeconomy,  said  Galen,  is  ruled  by  invariable  laws,  or  can  be 
subject  to  the  same  accurate  results  and  calculations,  as  an  inanimate  ma- 
chine, (Nilestin  corpore  viventi  filane  sincerum.  GALEN.)  Thus,  respiration, 
which  connects  the  external  and  assimilating  function,  furnishes  the  blood 
with  the  principle  which  is  to  keep  up  the  action  of  the  brain,  and  to  ex- 
cite musculai  contractions.  On  the  other  hand,  the  motion  of  the  mus- 
cles is  of  use  in  the  distribution  of  the  humours,  and  concurs  in  the  phe- 
nomena of  assimilation.  The  brain,  by  means  of  the  eighth  part  of  nerves, 
holds  influence  over  the  stomach.  The  sensations  of  taste  and  smell  seem 
to  preside,  in  an  especial  manner,  over  the  choice  of  food  and  of  air,  and 
to  belong  rather  to  the  digestive  and  respiratory  functions,  than  to  those 
of  the  intellect,  or  of  thought. 

We  have  seen  in  this  kind  of  general  introduction  of  the  study  of  phy- 
siology, what  idea  is  to  be  formed  of  that  science  as  well  as  of  life,  the 
study  of  which  is  its  object ;  into  how  many  classes  the  beings  in  nature 
may  be  divided,  and  into  how  many  elements  they  are  resolvable;  what 
differences  exist,  between  inorganized,  organized  and  living  bodies, 
between  plants  and  animals;  how  life  is  complicated,  modified,  and  ex- 
tended, in  the  immense  series  of  beings  which  are  endowed  with  it, from 
the  plant  to  man ;  anc4  in  further  particularizing  the  object  under  our 
consideration,  we  have  examined,  what  are  the  organs  which,  by  their 
union,  form  the  human  machine ;  what  powers  govern  the  exercise  of 
their  functions  :  then,  we  have  laid  down  the  fundamental  laws  of  sensi- 
bility and  contractility,  we  have  spoken  of  sympathies  and  habits,  of  the 
internal  nervous  apparatus,  which  unites,  collects,  and  systematizes  the 
organs  of  the  assimilating  function ;  we  have  endeavoured  to  determine 
from  facts,  the  existence  of  the  cause  which  subjects  living  beings  to  a 
set  of  laws  very  different  from  those  which  inorganic  matter  obeys.  The 
knowledge  of  these  laws  is  the  light  which  is  to  guide  us  in  the  applica- 
tion to  physiology  of  the  accessory  sciences.  Finally,  in  the  arrangement 
of  the  objects  which  this  science  considers,  I  have  adopted  a  more  sim- 
ple and  natural  division  than  any  hitherto  employed. 

I  shall  close  this  preliminary  discourse,  by  saying  a  few  words  on  the 
order  adopted  in  the  distribution  of  the  chapters.  I  might  have  begun  by 
a  view  of  the  external  functions,  as  well  as  those  of  assimilation  or  nutri- 
tion, of  sensation,  or  of  digestion.  I  have  given  preference  to  the  func- 
tions of  assimilation,  because  of  all  others,  they  are  the  most  essential  to 
existence,  and  their  exercise  is  never  interrupted,  from  the  instant  in 
which  the  embryo  begins  to  live,  till  death.  In  beginning,  with  an  ac- 
count of  them  we  imitate  nature  therefore,  who  imparts  to  man  this  mode 
of  existence,  before  she  has  connected  him  with  outward  objects,  and  who 
does  not  deprive  him  of  it,  until  the  organs  of  sense,  of  motion,  and  of 
the  voice,  have  completely  censed  to  act. 

As  to  the  course  which  has  been  followed  in  the  arrangement  of  the 
functions  that  belong  to  the  same  order,  or  which  concur  in  the  same  end, 
it  was  too  well  laid  down  by  nature,  to  .allow  us  to  depart  from  it.  I  have* 
thought  it  right  that  the  consideration  of  the  voice  should  immediately 
precede  that  of  generation,  in  order  that  the  arrangement  might,  at  a 
glance,  show  the  connexion  which  exists  between  their  phenomena. — 
Several  animals  us.e  their  voice  only  during  the  season  of  love ;  the  birds 
which  sing  at  all  times  have,  during  that  period,  a  more  powerful  and  so- 
norous voice.  When  man  becomes  capable  of  reproduction,  his  vocal 


67 

organs  suddenly  become  evolved,  as  though  nature  had  wished  to  inform 
him,  that  it  is  through  them  he  is  to  express  his  desires  to  the  gentle  be- 
ing who  may  sympathize  in  them.  The  voice,  therefore,  serves  as  a  na- 
tural  connexion  between  the  external  functions,  and  those  which  are  em- 
ployed in  the  preservation  of  the  human  species. 

The  voice,  which  leads  so  naturally  from  the  functions  which  establish 
our  external  relations,  to  those  whose  end  is  the  preservation  of  the  spe- 
cies, is  still  more  intimately  connected  with  motion.  It  is,  in  a  manner, 
the.  complement  of  the  phenomena  of  locomotion ;  by  means  of  it,  our  com- 
munication with  external  objects  is  rendered  easier,  more  prompt,  and 
more  extensive  :  it  depends  on  muscular  action,  and  is  the  result  of  vo- 
luntary motion.  Finally,  these  motions  sometimes  supply  the  place  of 
speech,  in  pantomime,  for  example,  and  in  the  greater  number  of  cases, 
the  language  of  action  concurs  in  adding  to  its  effect.  Every  thing-,  there- 
fore, justifies  me  in  placing  this  function  after  motion,  in  separating  it 
from  respiration,  with  which  every  other  author  has  joined  it,  without 
considering  that  the  relation  between  the  voice  and  respiration  is  purely 
anatomical,  and  can,  therefore,  in  nowise  apply  to  physiology. 

I  have  placed  after  generation,  an  abridged  account  of  life  and  death, 
in  which  will  be  found,  whatever  did  not  belong  to  any  of  the  preceding 
divisions.  The  necessity  of  this  appendix,  containing  the  history  of  the 
different  periods  of  life,  that  of  the  temperaments  and  varieties  of  the  hu- 
man species,  that  of  death  and  putrefaction,  arises  from  the  impossibility 
of  introducing  into  the  particular  history  of  the  functions,  these  general 
phenomena  in  which  they  all  participate. 


.FIRST  CLASS. 


LIFE  OF  THE  INDIVIDUAL, 


FIRST  ORDER. 


FUNCTIONS  OF  ASSIMILATION, 


OB,  JTTKCTIOSrS  WHICH  ABE  SUBSBBVIENT  TO  THE  PBESEBVATIOW  Ofc  TH£ 
INDIVIDUAL,  Bt  ASSIMILATING  TO  HIS  SUBSTAJTCEfHi:  JOOI> 
BY  WHICH  HE  IS  HQUBISHEID 


NEW  ELEMENTS 


OF 


PHYSIOLOGY 


CHAPTER    I. 


OF  DIGESTION. 

I.  Digestion  is  a  function  common  to  all  animals,  by  which  substances 
extraneous  to  them,  are  introduced  into  their  body,  and  subjected  to  the 
action  of  a  peculiar  system  of  organs,   their  qualities  altered,  and  a  new 
compound  formed,  fitted  to  their  nourishment  and  growth. 

II.  General  considerations  on  the  Digestive  organs.     Animals  alone  are 
provided  with  organs  of  digestion ;  all  of  them,  from  man  down  to  the 
polypus,  contain  an  alimentary  cavity,  variously  shaped.     The  existence 
of  a  digestive  apparatus  may,  therefore,  be  taken  as  the  essential  charac- 
teristic of  the  animal  kind.    In  man,  this  apparatus  consists  of  a  long  tube 
extending  from  the  mouth  to  the  anus  ;  within  this  canal,  there  empty 
themselves  the  excretory  ducts  of  several  neighbouring  glands,  that  secrete 
fluids  fit  for  changing,  for  liquefying,  and  animalizing  the  alimentary  sub- 
stance.    The  different  parts  of  this  digestive  tube  are  not  of  equal  capaci- 
ty; at  first,  enlarged  in  the  part  whjch  forms  the  mouth  and  pharynx,  it 
becomes  narrower  in  the  oesophagus;  this  last,  dilating  considerably, 
forms  the  stomach,  which  again  contracting,  is  continued  down  under  the 
name  of  intestine.     The  tube  itself  varies  in  size  in  different  parts  of  its 
extent:  and  it  is  by  the  consideration  of  these  differences  of  size,  that 
anatomists  have  principally  been  guided  in  their  divisions. 

The  length  of  the  digestive  tube  is  from  five  to  six  times  the  length  of 
the  whole  body,  in  an  adult:  it  is  greater  in  proportion  in  a  child.  At 
this  age,  likewise,  digestion  is  more  active,  and  proportioned  to  the  ne- 
cessities of  growth  in  the  individual.  The  digestive  cavity  is  in  man  open 
<it  both  extremities ;  in  some  animals,  in  the  zoophyte  for  example,  one 
opening  serves  the  purpose  of  mouth  and  of  anus,  receives  the  food,  and 
ejects  the  excrementitious  remains. 

The  extent  of  the  digestive  canal  is  according  to  the  nature  of  the  ali- 
ments on  which  the  animals  feed  :  the  less  those  aliments  are  analogous 
in  their  nature  to  the  substance  of  the  animal  they  are  to  nourish, 
the  longer  must  they  remain  in  his  body  to  undergo  the  necessary  changes. 
Therefore,  it  is  observed,  that  the  intestine  of  graminivorous  animals  is 
very  long,  their  stomach  very  capacious,  and  often  complex,  while  carni- 
vorous animals  have  their  intestinal  canal  short  and  strait, and  so  arranged, 


72 

that  the  animal  substances  which  are  most  nourishing,  in  least  bulk,  of 
easy  and  rapid  digestion,  which,  by  too  long  a  stay  in  the  intestines, 
might  become  putrid,  pass  readily  through  it.  In  this  respect,  man  holds 
a  middle  station  between  those  animals  which  feed  on  vegetables,  and 
those  which  feed  on  animal  substances.  He  is,  therefore,  equally  fitted 
for  these  two  kinds  of  food;  he  is  neither  exclusively  herbivorous,  nor 
nor  carnivorous,  but  omnivorous  or  polyphageus.  This  question,  of  such 
easy  solution,  has  long  employed  physicians,  naturalists,  and  philoso- 
phers; each  bringing,  in  favour  of  his  opinion,  very  plausible  arguments, 
drawn  from  the  form  and  number  of  the  teeth,  from  the  length  of  the  in- 
testinal canal,  from  the  force  of  its  parietes,  8tc. 

The  parietes  of  the  digestive  tube  are  essentially  muscular;  a  mucous 
membrane  lines  its  inside,  forming  within  it  various  folds ;  lastly,  a 
a  third  coat  is  accidentally  placed  over  the  other  two ;  and  is  furnished 
by  the  pleura  to  the  oesophagus,  by  the  peritoneum  to  the  stomach,  as 
well  as  to  the  intestinal  canal. 

The  characteristic  of  this  third  coat  is,  that  it  does  not  cover  the  whole 
surface  of  the  parts  of  the  tube  to  which  it  is  applied.  The  muscular  coat 
may  be  considered  as  a  long  hollow  muscle,  extending  from  the  mouth  to 
the  anus,  and  formed  throughout  almost  all  the  whole  of  its  length,  by  two 
layers  of  fibres,  the  one  set  longitudinal,  the  other  circular.  The  will  di- 
rects the  motions  of  the  two  extremities,  while  the  rest  of  its  course  is 
not  under  its  controul.  In  the  cells  of  the  tissue  which  unites  its  surfaces 
to  the  other  coats,  fat  never  accumulates,  which  might  have  impeded  its- 
contractions,  and  straitened  and  even  obliterated  the  tube  along  which  the 
food  was  to  pass*. 

III.  Of  food,  solid  and  liquid.  The  aliments  which  nourish  man  are  ob- 
tained from  vegetables,  or  from  animals.  The  mineral  kingdom  furnishes 
only  condiments,  medical  substances,  or  poisonsj. 

By  aliment  is  meant  whatever  substance  affords  nutrition,  or  whatever 
is  capable  of  being  acted  upon  by  the  organs  of  digestion.  Substances 
which  resist  the  digestive  action,  those  which  the  gastric  juice  cannot 
sheathe,  whose  asperities  it  cannot  soften  down,  whose  nature  it  catvnot 
change,  possess  to  a  certain  degree  the  power  of  disturbing  the  action  of 
the  digestive  tube,  which  revolts  from  whatever  it  cannot  overcome:  there 
is  no  essential  difference  between  a  medical  substance  and  a  poison.  Our 
most  active  remedies  are  obtained  from  among  the  poisonous  substances; 
tartar  emetic,  corrosive  sublimate,  opium,  all  of  them  remedies  of  so 
much  efficacy  in  skilful  hands,  when  administered  unseasonably,  or  in  too 

*  The  digestive  tube  comprehends,  1.  the  mouth ;  2.  the  pharynx ;  3.  the  oesopha- 
gus; 4.  the  stomach;  5.  the  small  intestines;  6.  the  large  intestines;  7. the  anus.  The 
commencement  and  termination  of  this  apparatus  are  subjected,  but  not  completely, 
to  the  influence  of  the  will.  Volition  and  sensation  are  distinctly  evinced  in  the  mouth 
and  pharynx  ;  in  the  oesophagus  and  stomach  the  influence  of  the  will  gradually  disap- 
pears, and  sensation  becomes  imperfect  and  peculiar.  It  is  in  consequence  of  the  dis- 
tribution of  voluntary  nerves,  in  greater  or  less  number,  to  certain  parts  of  the  digestive 
canal,  and  of  the  accession  thus  brought  to  the  ganglial  system  of  nerves  with  which  it 
is  chiefly  supplied,  that  many  of  the  sensations  and  operations  which  belong  to  its  upper 
portion,'as  the  pharynx,  oesophagus  and  the  stomach,  are  so  peculiar,  and  so  difficult  of 
explanation. —  Copland. 

\  MACKNJUE  arranges  the  aliments  which  nourish  man  according  to  the  immediate 
principle  which  predominates  in  their  composition.  After  this  manner  he  distinguishes 
nine  classes;  namely,  farinaceous,  mucilaginous,  saccharine,  acidulated,  oleaginous, 
milky  or  cheesy,  gelatinous,  album: nous.  f>Tv!  lihrinous  pTim.i'nts — Copland, 


73 

g-trong  doses,  act  as  most  violent  poisons;  they  forcibly  resist  the  diges- 
tive powers,  and  furnish  them  nothing  to  be  acted  upon,  while  mild  and 
inert  substances  yield  to  these  powers,  and  come  under  the  class  of  ali- 
ments. What  then  is  to  be  thought  of  our  ptisans,  of  chicken  and  veal 
broth,  and  other  such  remedies?  That  they  are  employed  to  deceive  the 
hunger  and  thirst  of  the  patient,  to  prevent  his  receiving  into  his  stomach, 
substances  whose  laborious  digestion  would  take  up  the  strength  requir- 
ed for  the  cure  of  the  disease;  that  they  are  mere  precautions'of  regimen, 
that  he  who  most  varies  this  kind  of  resource,  can  only  be  said  to  adopt 
a  treatment  of  expectation,  leaving  to  nature  alone,  the  care  of  exciting 
those  salutary  motions  which  are  to  bring  about  a  cure.  Why  do  cer- 
tain vegetable  purgatives,  as  manna  and  tamarinds,  produce  so  little  ef- 
fect, even  though  given  in  large  doses?  Because  these  substances  contain 
many  nutritious  particles  capable  of  being  assimilated,  so  that  strong 
constitutions  digest  them,  and  completely  neutralize  their  irritating  or 
purgative  qualities.  An  animal  or  vegetable  substance,  though  essential- 
ly nutritious,  may  act  as  a  medicine,  or  even  as  a  poison,  when,  in  con- 
sequence of  the  extreme  debility  of  the  digestive  tube,  or  because  it  has 
not  been  sufficiently  divided  by  the  organs  of  mastication*  it  resists  the 
digestive  action.  Thus  surfeits  are  brought  on  because  the  stomach  is 
debilitated,  because  it  is  oppressed  by  too  great  a  mass  of  substances,  or 
because,  having  been  imperfectly  triturated,  they  are  insoluble.  It  is  in 
considerations  of  this  kind,  that  the  true  foundations  of  materia  medica 
are  laid. 

Mineral  substances  are  of  a  nature  too  heterogeneous  to  our  own,  to  ad- 
mit of  being  converted  into  our  substance.  It  appears  that  their  elements 
require  the  elaboration  of  vegetable  life;  hence,  it  has  been  justly  ob- 
served, that  plants  are  laboratories  in  which  nature  prepares  the  food  of 
animals. 

Aliments  obtained  from  plants  are  less  nutritious  than  those  furnished 
by  the  animal  kingdom,  because  in  a  given  bulk,  they  contain  fewer  parts 
that  can  be  assimilated  to  our  own  substance.  Of  all  the  parts  of  vegeta- 
bles, the  most  nourishing  is  their  amylaceous  fecula,  but  it  yields  the 
more  readily  to  the  action  of  the  digestive  organs,  from  having  already 
experienced  an  incipient  fermentation ;  on  that  account,  leavened  bread 
is  the  best  of  vegetable  aliments.  The  flesh  of  young  animals  is  less 
nourishing  than  that  of  the  full  grown,  although,  at  an  early  age,  the  flesh 
of  the  former  abounds  more  in  gelatinous  juice's;  for,  this  abundant  gela- 
tine wants  the  necessary  degree  of  consistence. 

However  various  our  aliments  may  be,  the  action  of  our  organs  always 
separates  from  them  the  same  nutritious  principles ;  in  fact,  whether  we 
live  exclusively  on  animal  or  vegetable  substances,  the  internal  composi- 
tion of  our  organs  does  not  alter;  an  evident  proof,  that  the  substance 
which  we  obtain  from  aliments,  to  incorporate  with  our  o\\n,  is  always 
the  same,  and  this  affords  an  explanation  of  the  saying  of  the  father  of 
physic,  "  There  is  but  one  food,  but  there  exist  several  forms  of  food," 

Attempts  have  been  made  to  ascertain  the  nature  of  this  alimentary 
principle,  common  to  all  nutritive  substances,  and  it  is  conjectured,  with 
some  probability,  that  it  must  be  analogous  to  gummy,  mucilaginous,  or 
saccharine  substances ;  they  are  all  formed  from  hydrogen  and  carbon,  are 
well  known  to  differ  chemically  only  in  the  different  proportions  of  oxy- 
gen which  they  contain.  Thus, sugar  is  a  kind  of  gum,  containing  a  con- 
siderable quantity  of  oxygen;  and  which  is  reduced,  in  a  certain  degree, 

K 


74 

to  the  state  of  starch,  when  brought  lo  fine  powder  by  means  of  a  rasp, 
for,  the  friction  disengaging  a  portion  of  its  oxygen,  deprives  it  in  part  of 
its  flavour,  and  leaves  it  an  insipid  taste,  similar  to  that  of  farinaceous 
substances.  Nothing,  in  fact,  nourishes  better,  more  quickly,  and  from 
a  similar  bulk,  than  substances  of  this  kind.  The  Arab  crosses  the  vast 
plains  of  the  desert,  and  supports  himself  by  swallowing  a  small  quantity 
of  gum  arabic.  The  nourishing  quality  of  animal  and  vegetable  jellies  is 
well  known';  saccharine  substances  soon  cloy  the  appetite  of  those  who  arc 
fondest  of  them:  In  decrepid  old  age,  some  persons  live  exclusively  on 
sugar;  I  know  several  in  that  condition,  who  spend  the  day  in  chewing 
this  substance,  which  is  a  laborious  employment  for  their  feeble  and 
toothless  jaws*.  Lastly,  milk,  the  sole  nourishment  of  the  early  periods 
of  life,  contains  a  great  proportion  of  gelatinous  and  saccharine  matter. 

Though  man,  destined  to  live  in  all  latitudes,  is  formed  to  subsist  on 
all  kinds  of  food,  it  has  been  observed,  that  the  inhabitants  of  warm  cli- 
mates generally  prefer  a  vegetable  dietf.  The  Bramins  in  India,  the  in- 
habitants of  the  Canary  Islands,  and  of  the  Brazils,  Sec.  who  live  almost 


*  MAGEXIUE  concluded  from  his  experiments,  that  no  animal  seems  capable  of  deriv- 
ing nutriment  from  any  substance  that  does  not  contain  some  portion  of  azote.  There 
are,  however,  many  circumstances  which  prove  the  contrary — ADAXSOX  asserts,  that 
the  Nomadie  Moors  have  scarcely  any  other  food  than  gum  Senegal.  HASSEL<VUIST  re- 
lates, that  a  caravan  of  Abyssinians,  consisting  of  1000  persons,  subsisted  for  two  months 
on  a  stock  of  gum  arabic  alone,  which  they  found  among1  their  merchandize  ;  and  it  is 
well  known,  that  negroes,  and  individuals  otherwise  imperfectly  fed,  soon  become  fat 
from  the  mastication  of  the  sugar-cane.  A  case  lately  came  under  our  observation, 
which  fully  exemplifies  the  nutritious  quality  of  sugar,  in  a  lady,  about  the  middle  age, 
who  consulted  us  respecting  great  and  increasing  corpulency.  Her  countenance  was 
full,  clear,  and  florid;  her  pulse  strong;  her  health  excellent;  and  her  strength  very 
considerable.  She  partook  of  animal  food  only  once  in  a  day,  and  then  in  a  small  quan- 
tity. She  never  took  suppers,  and  WHS  very  moderate  in  the  use  of  fluids.  She  had  al- 
ways taken  considerable  exercise  on  foot,  and  even  up  to  the  period  at  which  we  saw 
her,  she  resorted  to  it  as  much  as  the  great  bulk  of  her  body  could  permit.  The  secret, 
however,  of  her  increasing  obesity  was  disclosed,  when  she  mentioned  her  insatiable  de- 
sire for  refined  sugar,  which  she  almost  hourly  made  use  of,  frequently  to  the  extent  of 
one  pound  we'.ght  daily.  She  considered  it  her  chief  article  of  diet.  She  reckoned  the 
average  quantity  which  she  used  at  about  three-fourths  of  a  pound  in  the  day.  Tea  or 
coii'ce  was  taken  by  her  sweetened  in  the  usual  way.  She  ate  the  sugar  in  the  solid  state, 
and  unaccompanied  with  any  other  article  of  diet :  the  finest  sort  only  was  relished. 
Her  digestive  functions  were  in  a  perfect  condition  ;  neither  cardialgia,  acidity,  nor  fla* 
tidence,  were  complained  of.  Her  teeth  were  sound.  She  found  her  corpulence  super- 
vene to  a  spare  habit  some  time  after  the  habit  of  eating  sugar  was  acquired.  She 
thought  that  the  obesity  increased  with  the  increase  in  the  quantity  of  sugar  she  consum- 
ed. The  habit  had  become  so  confirmed,  at  the  time  which  We  saw  her,  that  she  con- 
ceived it  to  be  quite  impossible  to  relinquish  it. —  Copland. 

-j-  These  inhabitants  of  warm  climates,  who  are  subjected,  in  consequence  of  the  na- 
ture of  the  situation  in  which  they  live,  to  a  moist  and  miasmatous  atmosphere,  generally 
adapt  their  vegetable  diet,  as  much  as  may  be  in  their  power,  to  the  circumstances  in 
which  they  are  placed.  They  endeavour,  by  adding  a  large  proportion  of  the  stimulant 
and  tonic  seeds  of  plants  to  their  aliments,  to  counteract  the  debilitating  and  septic  in- 
fluence of  the  air  which  they  breathe,  and  to  other  causes  to  which  they  are  more  or  less 
opposed.  To  them  the  hot  spices  are  the  chief  condiment,  and  even  prophylactic  ; 
without  the  use  of  these,  their  very  aliments  would  become  a  source  of  disease  ;  the 
various  kinds  of  parasitical  animals,  which  prey  on  man,  would  abound  to  the  most 
loathsome  degree,  and  they  would  be  continually  the  subject  of  dysentery,  and  the 
other  diseases  which  imperfect  or  improper  nourishment  and  an  unwholesome  climate 
induce.  The  hot  spices  are,  to  individuals  so  circumstanced,  more  requisite  than  salt 
is  to  the  inhabitants  of  temperate  or  cold  ctimates,  who  live  chiefly  on  animal  food,-^ 
Copland, 


75 

exclusively  on  herbs,  grain,  and  roots,  inhabit  a  climate,  against  the  ex 
cessive  heat  of  which  they  have  to  seek  means  of  protection ;  now,  the 
digestion  of  vegetables  is  attended  with  less  heat  and  irritation.  The 
philosophical  or  religious  sects,  by  which  the  abstinence  from  the  animal 
food  was  <3^^Hered  a  meritorious  act,  were  all  instituted  in  warm  cli- 
mates. The  school  of  Pythagoras  flourished  in  Greece,  and  the  ancho- 
rets, who,  in  the  beginning  of  the  Christian  religion,  peopled  the  solitudes 
of  Thebais,  could  not  have  endured  such  long  fastings,  or  supported  them- 
selves on  dates  and  water,  in  a  more  severe  climate.  So  that  the  monks 
that  removed  into  different  parts  of  Europe,  were  obliged  to  relax 
from  the  excessive  severity  of  such  a  regimen,  and  yielded  to 'the  irre- 
sistible influence  of  the  climate;  the  most  austere  came  to  add  to  vege- 
tables, which  formed  the  base  of  their  food,  eggs,  butter,  fish,  and  even 
water-fowl.  In  books  of  casuistry,  it  may  be  seen,  on  what  ridiculous 
grounds  there  was  granted  a  dispensation  in  favour  of  plovers,  of  water- 
hens,  wild  ducks,  snipes,  scoters,  birds  whose  brown  flesh,  more  animal- 
ized,  and  more  heating,  ought  to  have  been  proscribed  from  the  kitchen 
of  monasteries,  much  more  strictly  than  that  of  common  poultry. 

Consider  what  is  the  alimentary  regimen  of  the  different  nations  on  the 
face  of  the  earth,  and  you  will  see,  that  a  vegetable  diet  is  preferred  by  the 
inhabitants  of  warm  countries:  to  them,  sobriety  is  an  easy  virtue;  it  is 
a  happy  consequence  of  the  climate.  Northern  nations,  on  the  contrary, 
are  voracious  from  instinct  and  necessity.  They  swallow  enormousquan- 
tities  of  food,  and  prefer  those  substances  which  in  digestion  produce  the 
most  heat. — Obliged  to  struggle  incessantly  against  the  action  of  cold, 
which  tends  to  benumb  the  vital  powers,  to  suspend  every  organic  mo- 
tion, their  life  is  but  a  continual  act  of  resistance  to  external  influences. 
Let  us  not  reproach  them  with  their  voracity,  and  their  avidity  for  ardent 
spirits  and  fermented  liquors.  Those  nations  that  inhabit  the  confines  of 
the  habitable  world,  in  which  man  is  scarcely  able  to  withstand  the  seve- 
rity of  the  climate,  the  inhabitants  of  Kamtschatka,  the  Samoiedes,  live 
on  fish,  that  in  the  heaps  in  which  they  are  piled  up,  have  already  under- 
gone a  certain  degree  of  putrefactive  fermentation.  Does  not  the  use  of  a 
food  so  acrid  and  heating,  that  in  our  elimate  it  would  inevitably  be  at- 
tended with  a  febrile  action,  prove  plainly  the  necessity 'of  balancing,  by  a 
vigorous  inward  excitement,  the  debilitating  influence  of  powers  that  are 
operating  from  without?  The  abuse  of  spirituous  liquors  is  fatal  to  the 
European  transported  to  the  burning  climate  of  the  West  Indies.  The 
Russian  drinks  spirituous  liquors  with  a  sort  of  impunity,  and  lives  on  to  an 
advanced  age,  amidst  excesses  under  which  an  inhabitant  of  the  south  of 
Europe  would  sink. 

This  influence  of  climate  affects  alike  the  regimen  of  man  in  health,  and 
that  of  man  in  sickness,  and,  it  has  been  justly  observed  of  medicine,  that 
it  ought  to  vary  according  to  the  places  in  which  it  is  practised.  Barley, 
ptisan,  honey,  and  a  few  other  substances,  the  greater  part  obtained  from 
the  vegetable  kingdom,  sufficed  to  Hippocrates  in  the  treatment  of  dis- 
eases, his  therapeutic  treatment  was,  in  almost  every  case,  soothing  and 
refreshing.  Physicians,  who  practise  in  a  climate  such  as  that  of  Greece, 
may  imitate  this  simplicity  of  the  father  of  physic.  Opium,  bark,  wine, 
spirits,  aromatics,  and  the  most  active  cordials,  are,  on  the  other  hand, 
the  medicines  suited  to  the  inhabitants  of  the  North.  The  English  phy- 
sicians use,  freely  and  without  risk,  these  medicines,  which  elsewhere 
would  be  attended  with  the  utmost  danger. 


To 

Simple  aqueous  drinks  promote  digestion,  by  facilitating  the  solution 
of  the  solids;  by  serving  as  a  vehicle  to  their  divided  parts;  and  when 
rendered  active  by  saline  or  other  substances,  as  spirituous  liquors  are  by 
alcohol,  they  are  further  useful  in  stimulating  the  organs,  and  exciting 
their  action. 

The  least  compound  drinks  are  possessed,  in  different  degrees,  of  this 
double  property  of  dissolving  solid  aliments,  and  of  stimulating  the  diges- 
tive organs.  The  purest  water  is  rendered  stimulating  by  the  air,  and  by 
the  salts  which  it  contains,  in  different  proportions;  and,  to  the  want  of 
that  stimulating  quality  is  to  be  attributed  the  difficult  digestion  of  dis- 
tilled water. 

The  drinks  best  suited  to  the  wants  of  the  animal  economy,  are  those 
in  which  the  stimulating  principles  are  blended,  in  due  proportions,  with 
the  water  which  holds  them  in  solution.  But  almost  all  the  fluids  which 
we  drink,  contain  a  certain  proportion  of  nutritious  particles.  Wine,  for 
example,  contains  these  nutritive  particles  in  greater  quantity,  as  it  is  the 
produce  of  a  warmer  climate,  and  as  saccharine  matter  predominates  in 
its  composition.  Thus,  Spanish  wines  are  in  themselves  nourishing,  and 
are  perhaps  fitter  to  satisfy  hunger  than  to  allay  thirst,  while  the  acidu- 
lous Rhenish  wines,  which  are  merely  thirst  allaying,  scarcely  contain 
any  cordial  quality.  Between  the  two  extremes  are  the  French  wines, 
which  possess,  in  a  nearly^equal  degree,  the  treble  advantage  of  diluting 
the  fluids,  of  stimulating  the  organs,  and  of  furnishing  to  the  animal  eco- 
nomy materials  of  nutrition. 

IV.  Of  hunger  and  thirst.  By  the  words  hunger  and  thirst  are  meant  two 
sensations,  which  warn  us  of  the  necessity  of  repairing  the  loss  which  our 
body  is  continually  undergoing  from  the  action  of  the  vital  principle.— 
Their  nature,  as  is  well  observed  by  M.  Gall,  is  not  better  known  than 
that  of  thought.  Let  us  endeavour  to  explain  the  phenomena  by  which 
they  are  attended. 

The  effects  of  a  protracted  abstinence  are,  a  diminution  of  the  weight 
of  the  body,  a  dimunition  which  becomes  sensible  in  the  course  of  twenty- 
four  hours  5  a  wasting  of  the  body  from  the  loss  of  fat,  discoloration  of 
the  fluids,  especially  the  blood,  loss  of  strength,  excessive  sensibility, 
sleeplessness,  with  painful  sensations  in  the  epigastric  region*. 

Death  from  inanition  is  most  easily  brought  on,  in  those  who  are  young 
and  robust.  Thus,  the  unfortunate  father,  whose  horrible  story  has  been 
related  by  Dante,  condemned  to  die  of  hunger,  and  shut  up  with  his  chil- 
dren in  a  dark  dungeon,  died  the  last,  on  the  eighth  day,  after  having  wit- 
nessed, in  the  convulsions  of  rage  and  despair,  the  death  of  his  four  sons, 
unhappy  victims  of  the  most  execrable  vengeance  every  recorded  in  the 
history  of  man.  Haller  has  related,  in  his  great  work  on  physiology, 
several  instances  of  prolonged  abstinence :  if  we  are  to  give  credit  to 
these  accounts,  some  of  which  are  deficient  in  the  degree  of  authenticity 
required  to  warrant  belief,  persons  have  been  known  to  pass  eighteen 
months,  two,  three,  four,  five,  six,  seven,  and  even  ten  years,  without  ta- 
king any  nourishment.  In  the  Memoirs  of  the  Edinburgh  Society  is 
found  the  history  of  a  woman  who  lived  on  whey  only  for  fifty  years.  The 
subjects  of  these  cases  are  mostly  weak,  infirm  women,  living  in  obscuri- 
ty and  inaction,  and  in  whom  life,  nearly  extinct,  just  showed  itself  in  an 


*  See  APPENDIX.  Note  1. 


almost  insensible  pulse,  an  unfrequent  and  indistinct  respiration.  It  is  a 
iact  well  worthy  of  observation,  that  the  muscles  and  viscera  of  some  of 
them,  when  examined  after  death,  shone  with  a  light  evidently  phospho- 
ric*. Can  it  he  that  phosphorus  is  the  result  of  the  lowest  degree  of  ani- 
rndization?  It  may  be  easily  conceived,  that  living  in  a  manner,  on  their 
own  substance,  the  fluids  in  such  persons  have  been  frequently  subjected 
to  the  causes  which  produce  assimilation  and  animaiization,  and  have  un- 
dergone the  greatest  alteration  of  which  they  are  capable. 

The  proximate  cause  of  hunger  has  by  some  been  conceived  to  depend 
on  the  friction  of  the  nervous  papillae  of  the  empty  stomach  on  each  other; 
by  others,  it  has  been  imputed  to  the  irritation  produced  on  its  parietes, 
by  the  accumulation  of  the  gastric  juice.  It  has  been  thought  to  depend 
on  the  lassitude  attending  the  permanent  contraction  of  the  muscular 
fibres  of  the  stomach ;  and  on  the  compression  and  creasing  of  the  nerves, 
during  that  permanent  constriction;  on  the  dragging  down  of  the  dia- 
phragm by  the  liver  and  spleen,  when  the  stomach  and  intestines  being 
empty,  cease  to  support  those  viscera:  a  dragging  which  is  the  greater, 
as  a  new  mode  of  circulation  takes  place  in  the  viscera,  which  are  sup- 
plied with  blood  by  the  caeliac  artery,  and  while  the  stomach  receives  less 
blood,  the  spleen  and  liver  increase  in  weight  and  size,  because  their  sup- 
ply is  increasedf. 

Those  who  maintain  that  hunger  depends  on  the  friction  of  the  pari- 
etes of  the  stomach  against  each  other,  when  brought  together  in  an 
empty  state,  adduce  the  example  of  serpents,  whose  stomach  is  purely 
membranous,  and  who  endure  hunger  a  long  time,  while  fowls,  whose 
powerful  and  muscular  stomach  is  able  to  contract  strongly  on  itself,  en- 
dure it  with  difficulty.  But  to  say  nothing  of  the  great  difference  of 
vitality,  in  the  organs  of  a  bird  and  of  a  reptile,  the  stomach  which  con- 
tinues closing  on  itself  as  it  is  emptied,  may  contract  to  such  a  degree  as 
scarcely  to  equal  in  size  a  small  intestine,  without  its  following,  as  a  ne- 
cessary consequence,  that  the  parietes  which  are  in  contact  should  exert 
on  each  other  any  friction,  on  which  the  sensation  of  hunger  may  depend. 


*  Nitidissima  viscera  sunt  animalium  fame  enectorum,  ei  argcntei  Jibrarum  fasiculi.-— 
JUiiEB,  Elem.  Phys.  torn.  VI.  page  183. 

\  The  most  prevalent  opinions  respecting  the  proximate  causes  of  hunger  are,  that  it 
is  owing  to  the  action  of  the  gastric  juice  on  the  stomach,  or  that  it  is  a  sensation  con- 
nected with  the  contracted  state  of  this  organ  and  the  corrugation  of  its  internal  mem- 
brane. It  is  not  unlikely  that  both  causes  may  contribute  to  the  production  of  this  sen- 
sation, in  consequence  of  the  impression  which  they  make  on  the  sentient  extremities 
of  these  cerebral  nerves  which  reinforce  the  vital  operations  of  the  stomach.  The  state 
of  the  absorbent  vessels,  and  the  irritation  which  the  gastric  fluid  induces  on  the  ex- 
tremities of  these  vessels,  during  an  empty  state  of  this  viscus,  ought  also  to  be  taken 
into  consideration  in  our  speculations  respecting  the  origin  of  this  sensation. 

The  following  experiment  of  Dr.  \V.  PHILIP,  detailed  in  his  excellent  work  on  indi- 
gestion, appears  to  confirm  the  opinion  that  the  influence  of  the  gastric  juice  on  the 
stomach  is,  in  some  way  or  other,  productive  of  the  sense  of  hunger. 

"  A  person  in  good  health  was  prevailed  upon  to  abstain  from  eating  for  more  than 
twenty  hours,  and  further  to  increase  the  appetite  by  more  exercise  than  usual.  At  the 
end  of  this  time  he  was  very  hungry  ;  but,  instead  of  eatine:,  excited  vomiting  by  drink- 
ing; warm  water,  and  irritating  the  tauces.  The  water  returned  mixed  only  with  a  ropy 
fluid,  such  as  the  gastric  fluid  is  described  to  be  by  Spallanzani,  or  as  I  have  myself  ob- 
tained it  from  the  stomach  of  a  crow.  After  this  operation,  not  only  all  desire  to  eat  was 
removed,  but  a  degree  of  disgust  was  excited  by  seeing-  others  eat.  He,  however,,  was 
prevailed  upon  to  take  a  little  milk  and  bread,  which  in  a  very  short  time  ran  into  the 
acetous  fermentati oh,  indicated  by  flatulence  and  acid  eructations." — Copland. 


TS 

In  fact,  the  presence  cf  food  is  necessary  to  determine  an  action  fcf  the 
parietes  of  the  stomach,  and  as  long  as  it  is  empty,  there  is  nothing  to 
call  forth  such  action. 

Those  who  think  that  hunger  is  mechanically  produced  by  the  weight 
of  the  spleen  and  liver  that  keeps  pulling  down  the  diaphragm,  which  the 
empty  stomach  no  longer  bears  up,  observe,  that  it  may  be  appeased,  for 
a  time,  by  supporting  the  abdominal  viscera  by  means  of  a  tight  girdle  ; 
that  hunger  ceases  as  soon  as  the  stomach  is  full,  before  the  food  can 
have  yielded  to  it  any  materials  of  nutrition.  On  this  hypothesis,  which 
is  purely  mechanical,  as  that  which  explains  hunger  by  the  irritation  of 
the  gastric  juice,  by  the  lassitude  of  the  contracted  muscles,  by  the  com- 
pression of  the  nerves,  how  shall  we  explain  the  fact,  that  when  the  hour 
of  a  meal  is  over,  hunger  ceases  for  a  time  ?  Ought  not  hunger,  on  the 
contrary,  to  be  considered  as  a  nervous  sensation  which  exists  in  the  sto- 
mach, is  communicated  by  sympathy  to  all  the  other  parts,  and  keeping 
up  an  active  and  continuous  excitement  in  the  organ  in  which  it  is  prin- 
cipally seated,  determines  into  it  the  fluids  from  all  parts  ?  This  pheno- 
menon, like  all  those  which  depend  on  nervous  influence,  is  governed  by 
the  laws  of  habit,  by  the  influence  of  sleep,  and  of  the  passions  of  the 
mind,  whose  power  is  so  great,  that  literary  men,  absorbed  in  meditation 
and  thought,  have  been  known  entirely  to  forget  that  they  required  food. 
Every  thing  which  awakens  the  sensibility  of  the  stomach,  in  a  direct  or 
sympathetic  manner,  increases  the  appetite,  and  occasions  hunger.  Thus, 
bulimia  depends,  sometimes,  on  the  irritation  of  a  tape-worm  in  the  or- 
gans of  digestion.  The  application  of  cold  to  the  skin,  by  increasing, 
from  sympathy,  the  action  of  the  stomach,  has  been  known  to  "occasion 
fames  canina^  of  which  several  instances  are  related  by  Plutarch  (Life  of 
Brutus.)  Ardent  spirits  and  highly  seasoned  food,  excite  the  appetite, 
even  when  the  stomach  is  overfilled.  Whatever,  on  the  contrary, 
blunts  or  renders  less  acute  the  sensibility  of  the  stomach,  renders  more 
endurable  or  suspends  the  sensation  of  hunger.  Thus,  we  are  told  by 
travellers,  that  the  Turkish  dervises  and  the  Indian  faquirs,  endure  long 
fasts,  because  they  are  in  the  habit  of  using  opium,  and  lull,  in  a  manner, 
by  this  narcotic,  the  sensibility  of  the  stomach.  Tepid  and  relaxing 
drinks  impair  the  appetite;  the  use  of  opiates  suspends  suddenly  the  ac- 
tion of  the  stomach. 

V.  OfThirtt.  The  blood  deprived  of  its  serosity,  by  insensible  per- 
spiration and  by  internal  exhalation,  requires  incessant  dilution,  by  the 
admixture  of  aqueous  parts,  to  lessen  its  acrimony;  and  as  the  serosity 
is  incessantly  exhausting  itself,  the  necessity  for  repairing  that  loss  is  ever 
urgent*.  The  calls  of  thirst  are  still  more  absolute  than  those  of  hunger, 


*  As  hunger  seems  to  depend  upon  a  certain  condition  of,  or  impression  made  upon, 
these  cerebral  nerves  distributed  to  the  stomach,  so  thirst  appears  to  arise  from  an  alter- 
ed state  of  the  fluids,  which  state  modifies  the  functions  of  the  vessels,  diminishes  or 
otherwise  alters  the  condition  of  the  fluids  secreted  in  the  mouth  and  fauces,  and  im- 
presses the  nerves  of  sensation,  in  these  situations,  in  such  a  manner  as  to  give  rise  to 
tiie  phenomenon  under  consideration. 

As  the  sense  of  thirst  is  induced  by  a  state  of  the  circulating  fluids,  which  would  be- 
come hurtful  to  the  system  were  it  to  continue  for  any  .considerable  period,  so  this  sen- 
sation is  to  be.regarded  in  the  light  of  a  watchful  guardian,  which  both  points  out  that 
state,  and  the  only  way  in  which  it  can  be  removed. 

The  super-abundance  of  saline  or  stimulating  substances  in  the  blood,  is  readily  indi- 
cated by  the  sensation  induced  in  the  mouth  and  fauces,  which  are  the  first,  parts  to 


79 

and  it  is  much  less. patiently  endured.  If  it  be  not  satisfied,  the  blood,  and 
the  fluids  which  are  formed  from  it,  become  more  and  more  stimulating, 
from  the  concentration  of  the  saline  and  other  substances  which  they  con- 
tain. The  genera!  irritation  gives  rise  to  an  acute  fever,  with  heat  and 
parching  of  the  fauces,  which  inflame,  and  may  even  become  gangrenous, 
as  happens  in  some  cases  of  hydrophobia.  English  sailors,  who  were 
becalmed,  had  exhausted  all  their  stock  of  fresh  water,  and  were  at  a  dis- 
tance from  land;  not  a  drop  of  rain  had  for  a  long  time  cooled  the  at- 
mosphere: after  having  borne,  for  some  time,  the  agonies  of  thirst,  fur- 
ther increased  by  the  use  of  salt  provisions,  they  resolved  to  drink  their 
own  urine.  This  fluid,  though  very  disgusting,  allayed  their  thirst;  but 
at  the  end  of  a  few  days,  it  became  so  thick  and  acrid,  that  they  were  in- 
capable of  swallowing  a  mouthful  of  it.  Reduced  to  despair,  they  expect- 
ed a  speedy  death,  when  they  fell  in  with  a  ship  which  restored  them  to 
hope  and  life.  Thirst  is  increased  every  time  that  the  aqueous  secretions 
are  increased;  thus,  it  becomes  distressing  to  a  dropsical  patient,  in 
whom  the  fluids  are  determined  towards  the  seat  of  effusion.  It  is  ex- 
cessive in  diabetes,  and  in  proportion  to  the  increased  quantity  of  urine. 
In  fever,  it  is  increased,  from  the  effect  of  perspiration,  or  because  in 
some  of  these  affections,  for  example  in  bilious  fevers,  the  blood  seems 
to  become  more  acrid.  Hence  the  advantage  of  cooling,  diluting,  and 
refreshing  drinks,  administered  copiously,  with  a  view  to  correct  the 
temporary  acrimony  occasioned  by  the  absence  of  a  great  quantity  of  the 
serous  parts  of  the  blood,  and  to  lessen  the  over  excitement  of  a  fluid  be- 
come too  stimulating. 

The  use  of  aqueous  drink  is  not  the  most  effectual  method  of  allaying 
thirst.  A  traveller  exposed  to  the  scorching  heat  of  summer,  finds  it  ad- 
vantageous to  mix  spirits  to  plain  water,  which  alone  does  not  stimulate 
sufficiently  the  mucous  and  salivary  glands,  whose  secretion  moistens 
the  inside  of  the  mouth  and  pharynx,  and  covers  these  surfaces  with  the 
substance  best  calculated  to  suspend,  at  least  for  a  time,  the  erethism  on 
which  thirst  appears  to  depend. 

VI.  On  Mastication*.  The  organs  employed  in  the  mastication  of  the 
food,  are  the  lips,  the  jaws,  and  the  teeth;  with  these  are  furnished,  the 
muscles  by  which  they  are  moved,  and  those  which  form  the  parietes  of 
the  mouth.  The  motions  of  the  lips  are  extremely  varied,  and  depend  on 

evince  the  deleterious  effects  of  these  substances  upon  the  animal  economy :  hence  the 
state  of  these  organs  is  an  important  index  to  the  condition  of  the  circulating  fluids,  and 
of  the  whole  system,  in  a  number  of  diseases. 

Those  physiologists  who  refer  the  operations  of  the  livingbody  to  a  galvanic  process, 
carried  on  by  the  nervous  system  on  the  fluids  contained  in  the  vascular,  especially  in 
the  capillaries,  assign,  as  the  proximate  causes  of  thirst,  a  deficiency  of  oxygen  and  an 
abundance  of  the  inflammable  materials  amongst  these  elements  which  constitute  the 
fluids  circulating  at  the  time  in  which  the  sensation  is  induced,  ("  Oxygenii  autem  de- 
fectum  et  phlogisticorum  abundantium  sitim  adducere.")  This,  or  a  similar  opinion,  is 
entertained  by  SPHENGEI,,  PROCHASKA,  BCIIBACH,  and  LENHOSSECK.  The  arguments 
which  these  systematic  writers  on  physiology  adduce,  as  well  as  the  experiments  of 
Dr.  PHILIP,  in  support  of  the  theory  which  ascribes  the  vital  phenomena  to  galvanic 
processes  taking  place  in  the  system,  deserve  to  be  calmly  considered  before  they  are 
designated  to  be  either  visionary  or  untenable. Copland. 

*  The  following  operations  are  comprehended  under  the  process  of  digestion,  name- 
ly,  1.  mastication  ;  2.  insalivation ;  3.  deglutition  ;  4.  the  action  of  the  stomach  ;  5.  the 
action  of  the  small  intestines;  6.  the  action  of  the  large  intestines;  7.  the  expulsion  of 
the  faeces — Copland, 


80 

the  single  or  combined  action  of  their  muscles,  by  which  the  greater  part 
of  the  face  is  covered,  and  which  may  be  enumerated  as  follows  : — Eleva- 
tors of  the  upper  lip  (caninus,  incisvus,  leva-tores  communes  labiorum  el  my- 
rtiformes.}  Depressors  of  the  under  lip  (triangularis  labiomm,  quadratus 
genx.)  Abductors  (buccinator,  zygomaticus  major  et  minor  ^  platysma 
myoides.}  Constrictors  (orbicularis  or  is.} 

VII.  The  motions  of  the  upper  jaw  are  so  confined,  that  some  have  de- 
nied that  it  has  any  motion:  it  nevertheless  rises  a  little*,  when  the  low- 
er jaw  descends;  but  it  is  principally  by  the  depression  of  the  latter  that 
the  mouth  is  opened.  The  muscles  at  the  back  of  the  neck,  and  that  part 
of  the  digastric  muscle  nearest  the  mastoid  process,  produce  a  slight  ele- 
vation of  the  upper  jaw,  which  moves  with  the  whole  head,  to  the  bones 
of  which  it  is  firmly  united.  This  connexion  of  the  upper  jaw  with  the 
bones  of  the  head,  renders  this  jaw  less  move  able  in  man  than  in  the 
greater  number  of  animals,  in  which,  freed  from  the  enormous  weight  of 
the  skull,  it  stretches  out  in  front  of  that  cavity,  over  the  lower  jaw.  As 
we  follow  downwards  the  scale  of  animal  existence,  the  motions  of  the 
upper  jaw  is  seen  to  increase,  the  further  we  descend  from  the  human 
species;  it  is  equal  to  that  of  the  lower  jaw,  in  the  reptiles,  and  in  several 
fishes :  hence  the  enormous  dimensions  of  the  mouth  of  the  crocodile  and 
shark;  hence  serpents  frequently  swallow  a  prey  of  a  bulk  greater  than 
their  own,  and  would  be  stiffocated,  but  for  the  power  they  possess,  of 
suspending  respiration  for  a  long  time,  and  of  waiting  patiently,  till  the 
gastric  juice  dissolves  the  food,  as  it  is  swallowed. 

In  the  act  of  mastication,  the  upper  jaw  may  be  considered  as  an  anvil, 
on  which  the  lower  jaw  strikes  as  a  moveable  hammer,  and  the  motions 
of  the  under  jaw,  the  pressure  it  exerts,  and  its  efforts,  would  soon  have 
disturbed  the  connexion  of  the  different  bones  of  which  the  face  is  formed, 
if  this  unsteady  edifice,  merely  formed  of  bones,  in  juxta  position,  or 
united  by  sutures,  were  not  supported,  and  did  not  transmit  to  the  skull, 
the  double  effort  which  presses  on  it  from  below  upwards,  and  pushes  it 
out  literally.  Six  vertical  columns,  the  ascending  apophyses  of  the  supe- 
rior maxillary  bones,  the  orbital*  processes  of  the  malar  bones,  and  the 
vertical  processes  of  the  palate  bones,  support  and  transmit  the  effort 
which  takes  place  in  the  first  direction,  while  the  zygomatic  processes 
forcibly  press  the  bones  of  the  face  against  each  other,  and  powerfully  re- 
sist separation  outwardly  or  laterally.  The  lower  jaw  falls  by  its  own 
weight,  when  its  elevators  are  relaxed;  the  external  pterygoid  muscles, 
and  those  attached  to  the  os  hyoides,  complete  this  motion,  the  centre  of 
which  is  not  in  the  articulation  of  the  jaw  to  the  temporal  bones,  but  cor- 
responds to  a  line  that  should  cross  the  coronoid  processes,  a  little  above 
the  angles  of  the  jaw.  It  is  around  this  axis,  that,  in  falling,  the  lower 
jaw  performs  a  motion  of  rotation,  by  which  its  condyles  are  turned  for- 
wards, while  its  angles  are  carried  backwards.  In  children,  the  coro- 
noid processes  standing  off  at  a  smaller  distance  from  the  body  of  the 
bone,  of  which  they  have  nearly  the  same  direction,  the  centre  of  motion 
is  always  in  the  glenoid  cavities,  which  the  condyles  never  quit,  however 
much  the  jaw  may  be  depressed.  By  this  arrangement,  nature  has  guard- 
ed against  dislocation,  which  would  have  been  frequent  at  an  early  period 


*  This  can  only  be  from  a  motion  of  the  whole  head  on  the  atlas ;  the  action  of  the 
posterior  belly  of  the  digastricus  is  a  mere  assumption.— Godman> 


81 

of  life  from  crying,  during  which,  the  jaw  is  depressed  beyond  measure, 
or  when  not  knowing  the  just  proportion  between  the  capacity  of  the 
mouth,  and  the  size  of  the  bodies  they  would  put  into  it,  children  endea- 
vour to  introduce  those  which  it  cannot  receive.  The  lower  jaw  forms 
a  double  bended  lever  of  the  third  kind,  in  which  the  power,  represented 
by  the  temporal,  masseter  and  internal  pterygoid  muscles,  lies  between 
the  fulcrum  and  the  resistance,  at  a  smaller  or  greater  distance  from 
the  chin. 

The  mode  of  articulation  of  the  jaw  to  the  temporal  bones,  allows  it 
only  a  motion  upwards  and  downwards,  in  which  the  teeth  of  both  jaws 
meet  like  the  blades  of  scissars,  and  a  lateral  motion*  in  which  the  teeth 
glide  on  each  other,  producing  a  friction  well  calculated  to  grind  the  food, 
which  in  the  first  part  of  the  act  of  mastication  was  torn  or  divided. 

VIII.  In  carnivorous  animals,   the  levator  muscles  of  the  under  jaw, 
especially  the  temporals  and  massetcrs,  are  prodigiously  large  and  pow- 
erful.    In  them,  the  coronoid  processes,  to  which  the  temporal  muscles 
are  attached,  are  very  prominent;  the  condyles  are  received  into  a  very 
deep  cavity  ;  while  in  herbivorous  animals,  on  the  contrary,  they  are  less 
strong  and  bulky,  and  the  pterygoid  muscles,  by  whose  action  the  lateral 
or  grinding  motion  is  performed,  are  stronger  and  more  marked.     The 
glenoid  cavities  are  also  in  them  wide  but  shallow,  so  that  they  allow  the 
condyles  to  move  freely  on  their  surface.     The  comparative  power  of  the 
levator  and  abductor  muscles  of  the  lower  jaw,  may  be  easily  appreciated, 
by  viewing  the  temporal  and  zygomatic  fossse.     Their  depth  is  always  in 
an  inverse  ratio,  and  proportioned  in  the  bulk  of  the  muscles  which  they 
contain.     In  carnivorous  animals,  the  zygomatic  arch,  to  which  the  mas- 
seter is  attached,  is  depressed,  and  seems  to  have  yielded  to  the  effort  of 
the  muscle.     In  the  point  of  view  which  we  have  just  taken,  man  holds  a 
middle  station  between  carnivorous  animals  and  those  which  feed  on  ve- 
getable substances ;  nothing,  however,  determines  his  nature  better  than 
the  composition  of  his  dental  arches. 

IX.  The  small  white  and  hard  bones  which  form  the  dental  arches,  are 
not  alike  in  the  animals  whose  jaws  are  furnished  with  them.     All  have 
not,  as  man,  three  kinds  of  teeth.     The  laniary*  teeth  are  not  to  be  met 
with,  in  the  numerous  class  of  rodentia,     Some  are  without  incisors;  the 
former  appear  more  fitted  to  tear  fibrous  tissues  which  offer  much  resist- 
ance.    In  carnivorous  animals,  they  are  likewise  very  long,  and  bent  like 


*  After  the  example  of  several  naturalists,  I  have  thought  it  right  to  give  that  name  to 
the  canine  teeth ;  in  the  first  place,  because  their  principal  use  being  to  lacerate  or 
tear  fibrous  tissues,  it  is  fit  that  they  should  have  a  name  from  their  manner  of  acting  on 
the  food,  as  is  the  case  with  the  incisors  and  molares ;  in  the  second  place,  because  thq 
word  canine  may  lead  to  an  erroneous  conception,  by  leading  to  a  belief  that  this  kind 
of  tooth  belongs  only  to  one  kind  of  carnivorous  animals,  while  they  are  stronger  and 
more  distinct  in  the  lion,  the  tyger,  Sec. 


The  teeth  differ  essentially  from  the  other  bones,  by  the  acute  sensibility  with  which 
they  are  endowed  ;  2dly,  by  the  nerves  which  may  be  traced  into  them,  while  they  seem 
to  be  wanting  in  every  other  part  of  the  osseous  system  ;  3dly,  by  the  mode  of  distribu- 
tion of  the  blood-vessels :  these  penetrate  into  them  at  an  aperture  which  is  seen  at  the 
extremity  of  their  root,  and  they  expand  in  the  mucous  membrane  contained  in  the 
tooth,  and  which  forms  the  most  essential  part  of  the  bone  ;  4thly,  by  their  not  under- 
going any  change  from  exposure  to  the  air,  a  property  which  they  owe  to  the  elmmel 


82 

Curved  pincers.  The  grinders  are  principally  employed  in  grinding  sub- 
stances  previously  divided  by  the  laniary  teeth,  which  tear  them,  or  by  in- 
cisors, which,  in  meeting  as  the  blades  of  scissars,  fairly  cut  them  through: 
the  latter,  of  which  each  jaw  contains  four,  acting  only  on  bodies  which 
present  but  a  slight  resistance,  are  placed  at  the  extremity  of  the  maxilary 
lever.  The  grinders  are  brought  nearer  to  the  fulcrum,  and  it  is  on  them 
that  the  great  stress  of  mastication  rests.  If  we  wish  to  crush  a  very  hard 
substance  v,  e  instinctively  place  it  between  the  last  large  grinders,  and  by 
thus  shortening  considerably  the  lever,  between  the  resistance  and  the  ful- 
crum, we  improve  on  the  lever  of  the  third  kind,  which  though  most  em- 
ployed in  the  animal  economy,  acts  the  most  unfavourably.  Xhe  laniary 
teeth  have  very  long  fangs;  which  lying  deeply  buried  in  the  alveolar  pro- 
cesses, give  them  a  degree  of  firmness  to  enable  them  to  act  powerfully, 
without  danger  of  being  loosened  from  their  situation, 

The  enamel  which  covers  the  teeth,  preserves  the  substance  of  the 
bone  exposed  to  the  contact  of  the  air,  from  the  injurious  effects,  which 
would  not  fail  to  result  from  direct  exposure,  and  as  enamel  is  much  hard- 
er than  hone,  it  enables  the  teeth  to  break  the  hardest  bodies  without  in- 
jury. The  concentrated  acids  soften  this  substance,  and  occasion  a  pain- 
ful affection  of  the  teeth.  The  sensibility  possessed  by  these  bones,  is 
seated  in  the  mucous  membrane  which  lines  their  inward  cavity,  through 
which  are  distributed  the  vessels  and  nerves,  which  enter  by  openings  at 
their  roots.  This  membrane  is  the  seat  of  a  great  number  of  diseases, 
to  which  the  teeth  are  subject.  The  enamel,  incessantly  worn  by  repeat- 
ed friction,  grows  and  repairs  its  waste.  The  alveolar  processes  which 
receive  the  fangs  of  the  teeth,  firmly  embrace  them,  and  all  of  them  be- 
ing exactly  conical  in  form,  every  point  of  these  small  cavities,  and  not 
merely  their  lower  part  at  which  the  nerves  and  vessels  enter,  supports 
the  pressure  which  is  applied  to  these  bones.  When  from  accidental 
causes,  or  in  the  progress  of  age,  the  teeth  are  gone,  their  alveoli  con- 
tract*, then  disappear;  the  gums,  a  reddish  and  dense  membranous  sub- 
stance, which  connects  the  teeth  to  the  sockets,  harden  and  become  cal- 
lous over  their  thinned  edges.  Old  men  who  have  lost  all  their  teeth, 
masticate  but  imperfectly,  and' this  circumstance  is  one  of  the  causes  of 
their  slow  digestion,  as  the  gastric  juice  acts  with  difficulty  on  food, 
whose  particles  are  not  sufficiently  divided. 

X.  Salivary  Solution.  The  above  mechanical  trituration  is  not  the  only 
change  which  the  food  undergoes  in  the  mouth.  Subjected  to  the  action 
of  the  organs  of  mastication,  which  overcome  the  force  of  cohesion  of 
its  molecules,  it  is  at  the  same  time  imbued  with  the  saliva.  This  fluid 
secreted  by  the  glands  placed  in  the  vicinity  of  the  mouth,  is  poured,  in 
considerable  quantity,  into  that  cavity  during  mastication. 

The  saliva  is  a  transparent  and  viscous  fluid,  formed  of  about  four  parts 
of  water  and  one  of  albumen,  in  which  are  dissolved,  phosphates  of  soda, 
of  lime,  and  of  ammonia,  as  well  as  a  small  quantity  of  muriate  of  soda; 

which  covers  them  externally.  It  has  been  said,  with  justicef,  that  Nature,  in  sheath- 
ing- the  tooth  with  this  covering,  hatf  imitated  the  process  of  tempering1,  by  means  of 
which,  we  harden  the  edge  of  steel  or  iron  tools. — Author's  Note. 

*  When  the  teeth  of  old  persons  are  removed,  or  fall  out,  the  alveoli  are  gradually, 
and  entirely  absorbed ;  this  is  what  is  meaiit  by  their  contraction. — Godman. 

f  We  should  say  very  ricTiculouslv,  as  no  analogy  exists  between  the  «  processes." — 


83 

like  all  other  albuminous  fluids,  it  froths  when  agitated,  by  absorbing 
oxygen,  for  which  it  appears  to  have  a  strong  affinity.  Its  affinity  for 
oxygen  is  such,  that  one  may  oxydize  gold  and  silver,  by  triturating 
in  saliva,  thin  leaves  of  those  metals  which  are  of  such  difficult  oxy- 
dizement. 

The  irritation  occasioned  by  the  presence  or  the  desire  of  food,  excites 
the  salivary  glands;  they  swell  and  become  so  many  centres  of  fluxion, 
towards  which  the  humours  flow  abundantly*.  Bordeu  first  called  the 
attention  of  physiologists,  to  the  great  quantity  of  nerves  and  vessels  re- 
ceived by  the  parotid,  maxillary  and  sublingual  glands,  from  the  carotid, 
maxillary  and  lingual  arteries,  from  the  portio  dura  of  the  seventh  pair  of 
nerves,  from  the  lingual  nerve  of  the  fifth  pair,  which  penetrate  their  sub- 
stance, or  pass  over  a  portion  of  their  surface.  This  great  number  of 
vessels  and  nerves  is  proportioned  to  the  quantity  of  saliva  which  is  se- 
creted, and  this  is  estimated  at  about  six  ounces  during  the  average  time 
of  a  meal.  It  flows  in  greater  quantity,  when  the  food  that  is  used  is 
acrid  and  stimulating:  it  mixes  with  the  mucus,  copiously  secreted  with 
the  mucous,  buccal,  labial,  palatine,  and  lingual  glands,  and  with  the  se- 
rous fluid,  exhaled  by  the  exhalent  arteries  of  the  mouth.  The  saliva 
moistens,  imbues,  and  dissolves  the  ball  formed  by  the  aliment,  brings  to- 
gether its  divided  molecules,  and  produces  on  them  the  first  change. 
There  can  be  no  doubt,  that  the  saliva  mixing  with  the  food  by  the  mo- 
tion of  the  jaws,  absorbs  oxygen,  and  unites  to  the  alimentary  substances, 
a  quantity  of  that  gas  fit  to  bring  about  the  changes  which  they  are  ult> 
mately  destined  to.  undergof. 

*  The  intimate  sympathy  or  consent  of  action  that  exists  between  the  functions  of 
the  stomach  and  the  salivary  apparatus,  by  means  of  the  nerves  which  chiefly  preside 
over  the  process  of  digestion  and  all  the  operations  of  secretion  and  nutrition,  is  strong-. 
ly  evinced  by  the  following1  fact.     An  individual,  in  an  attempt  to  commit  suicide,  divi- 
ded the  oesophagus  to  a  considerable  extent.   During  the  attempts  to  preserve  his  exist- 
cnce,  food  was  conveyed  into  the  stomach  by  means  of  a  tube.     As  soon  as  the  aliments 
were  received  into  this  viscus,  the  salivary  secretion  became  abundant,  although  the 
process  of  mastication  was  not,  of  course,  attempted. —  Copland. 

f  The  specific  gravity  of  saliva  is  1,038.  It  mixes  with  water  only  by  trituration,  has 
a.  strong  affinity  for  ox\gen,  absorbs  it  readily  from  the  air,  and  gives  it  out  again  to 
ether  bodies.  Whether  it  possesses  any  affinity  for  nitrogen,  has  not  been  shown  ;  nor 
has  the  absorption  of  oxygen  by  this  fluid,  during  t'.ie  process  of  mastication,  been  suf- 
ficiently attended  to  in  our  speculations  respecting  the  pi-ocess  of  digestion.  We  can 
hardly  suppose  that  it  takes  up  oxygen  without  a  portion  of  nitrogen,  or  of  common  air. 
If  any  quantity  of  the  latter  be  mixed  with  it  during  the  insalivation  of  the  food,  an  evi- 
dent source  is  disclosed  from  which  nitrogen  may  be  conveyed  into  the  circulating1 
fluids,  in  addition  to  that  which  is  derived  from  the  ordinary  aliments. 

The  affinity  which  the  saliva  has  for  oxygen,  and  the  readiness  with  which  it  gives 
out  this  substance  to  other  bodies,  explains  the  reason  why  gold  or  silver  triturated  with 
it  is  oxydized  ;  and  why  mercury  soon  disappears  when  triturated  with  saliva.  Hence, 
also,  the  reason  why  the  application  of  saliva  to  sores  is  an  useful  remedy,  and  one  to. 
which  the  lower  animals  have  constant  recourse. 

The  constituents  of  saliva,  according  to  BE  RZ  EMUS,  are  as  follows  : 

Water, 992.9 

Peculiar  animal  matter  (precipitated  by  acet.  plumbi)  mucus  of  BOSTOCK,      2.9 

Mucus* — albumen  of  BOSTOCK  and  TUOMPSOX, 1.4 

Alkaline  muriates, 1.7 

Lactate  of  soda  and  animal  matter, 0.9 

Pure  soda, : 0.2 

1000.0 

*  The  mucous  or  albuminous  portion  lias  all  the  characters  of  albumen.    On  incine- 


84 

XI.  The  muscular  parietes  of  the  mouth  are,  during  mastications,  in 
perpetual  action.     The  tongue  presses  on  the  food,   in  every  direction, 
and  brings  it  under  the  teeth  ;  the  muscles  of  the  cheek,  especially  the 
buccinator,  against  which  the  food  is  pressed,  force  it  back  again  under 
the  teeth,  that  it  may  be  duly  triturated.     When  the  food  has  been  suf- 
ficiently divided,  and  imbued  with  saliva,  the  tip  of  the  tongue  is  carried 
to  every  part  of  the  mouth,  and  the  food  is  collected  on  its  upper  surface. 
The  food  having  been  thus  completely   gathered  together,  the  tongue 
presses  it  against  the  roof  of  the  mouth,  and  turning  its  tip  upwards  and 
backwards,  at  the  same  time  that  its  base  is  depressed,  there  is  offered 
to  the  food  an  inclined  plane,  over  which  the  tongue  presses  it  from  be- 
fore backwards,  to  make  it  clear  the  isthmus  of  the  fauces,  and  to  thrust 
it  into  the  oesophagus.     In  this  course  of  the  food  along  the  pharynx, 
and  into  the  oesophagus,    cosists  deglutition,   a  function   which  is  as- 
sisted by  the  co-operation  of  several  organs  whose  mechanism  is  rather 
complicated. 

XII.  Deglutition.    In  the  process  of  deglutition,  the  mouth  closesby  the 
approximation  of  both  jaws ;  at  the  same  time,  the  submaxillary  muscles, 
the  digastrici,  the  genio-hyoidei^  the  mylo-hyoidci^   Sec.  elevate  the  larynx 
and  pharynx,  by  drawing  down  the  os  hyoides  together  with  the  lower 
jaw,  which  is  fixed  by  its  levator  muscles.     The  hyoglossus  muscle,  at 
the  same  time  that  it  elevates  the  os  hyodies,  depresses  and  carries,  back- 
wards the  base  of  the  tongue*.     Then  the  epiglottis,  situated  between 
these  two  parts,  which  are  brought  together,  is  pushed  downwards  and 
backwards  by  the  base  of  the  tongue,  which  lays  it  over  the  opening  of 
the  larynx.     The  alimentary  mass,  pressed  between  the  palate  and  the 
upper  surface  of  the  tongue,  slides  on  the  inclined  plane  formed  by  the 
latter,   and  pressed  by  its  tip,  which  bends  back,  clears  the  isthmus  of 
the  fauces.     The  mucous  substance  which  excludes  from  the  surface  of 
amygdalae  further  facilitates  the  passage  of  the  food.     When  the  food 
has  thus  drooped  into  the  pharynx,  the  larynx,  which  had  risen,  and  had 
come  forward,  and  which  in  that  motion  had  drawn  the  pharynx  along 
with  it,  descends  and  falls  backwards.    This  last  organ  stimulated  by  the 

*  In  a  memoir  read  before  the  French  Institute,  in  1813,  M.  Magendie  related  two 
cases  in  which  deglutition  was  performed  without  difficulty,  although  the  epiglottis  was 
destroyed.  He  attributes  the  closure  of  the  larynx  to  the  action  of  the  arytenoid  mus- 
cles, which  are  generally  thought  to  be  exclusively  appropriated  to  the  Voice. — God- 


ration  its  ashes  contain  a  considerable  portion  of  phosphate  of  lime,  although  none  of 
that  salt  can  be  detected  in  it  before  incineration.  It  is  this  pecular  substance  which 
adheres  to  the  teeth,  and  gives  origin  to  the  tartar  which  surrounds  them.  This  deposi- 
tion, according  to  BERZELITJS,  is  composed  of 

Earthy  phosphates, 79.0 

Undecomposed  mucus, 12.5 

Peculiar  salivary  matter, 1,0 

Animal  matter  soluble  in  mur.  acid, 7.5 

100 

It  cannot  be  doubted,  that,  like  the  other  animal  fluids,  the  constitution  of  this  is  lia- 
ble to  changes  from  disease.  It  is,  however,  a  subject  which  has  excited  little  atten- 
tion among  chemists  and  physiologists.  BHrGsrAT.Ei.Lr  found  the  saliva  of  a  patient 
labouring  under  an  obstinate  venereal  disease,  impregnated  with  oxalic  acid. 

The  concretions  which  sometimes  form  in  the  salivary  ducts,  chiefly  consist  of  phos- 
phate of  lime  ia  coagulated  albumen. —  Copland 


85 

pi-esence  of  the  food,  contracts,  and  would  in  part  send  it  back  in  a  re- 
trograde direction,  by  the  nasal  fossae,  if  the  velum  palati,  elevated  by 
the  action  of  the  levatorcs  palati,  stretched  transversely  by  the  tensores 
palati,  was  not  applied  to  their  posterior  apertures,  and  towards  the 
openings  of  the  Eustachian  tubes.  Sometimes  this  obstacle  is  overcome, 
and  the  food  returns,  in  part  by  the  nostrils.  This  happens,  when  during 
the  act  of  deglutition,  we  attempt  either  to  laugh  or  speak.  At  such 
times,  the  air,  expelled  from  the  lungs  with  a  certain  degree  of  force, 
elevates  the  epiglottis,  and  meeting  the  alimentary  mass,  pushes  it  back 
towards  the  nostrils  through  which  it  is  to  pass.  The  isthmus  faucium 
is  closed  against  the  return  of  the  food  into  the  mouth,  by  the  swelling 
of  the  base  of  the  tongue,  raised  by  the  action  of  the  constrictor  fauciura, 
and  of  the  constrictor  pharyngis  superior,  which  are  small  muscles  con- 
tained in  the  thickness  of  the  pillars  of  the  velum. 

The  alimentary  mass  is  directed  towards  the  oesophagus,  and  is  thrust 
into  that  canal,  by  the  peristaltic  contractions  of  the  pharynx,  which  may 
be  considered  as  the  narrow7  part  of  a  funnel-like  tube.  The.  solid  food 
passes  behind  the  uperture  of  the  larynx,  which  is  accurately  covered 
over  by  the  epiglottis.  The  liquids  flow  along  the  sides  of  that  opening, 
along  two  channels  easily  distinguished.  They  are  always  of  a  more 
difficult  deglutition  than  the  solids  ;  the  molecules  of  a  fluid  have  an  in- 
cessant tendency  to  separate  from  one  another,  and  to  prevent  this  sepa- 
ration, the  organs  are  obliged  to  use  greater  exertion,  and  to  embrace 
with  more  precision  the  substance  that  is  swallowed.  Thus,  it  is  to  be 
observed,  in  those  cases  in  which  deglutition  is  prevented  by  some  or- 
ganic affection  of  the  oesophagus,  that  the  patients,  though  they  have  the 
power  of  swallowing  solid  food,  find  it  difficult  to  swallow  a  few  drops  of 
a  liquid,  and  are  tortured  with  thirst,  though  they  have  still  the  power 
of  satisfying  their  hunger*. 

The  deglutition  of  air  and  of  gaseous  substances,  is  still  more  difficult, 
than  that  of  liquids,  because  these  elastic  fluids  are  much  less  coercible, 
and  it  requires  considerable  practice,  to  transmit  a  mouthful  of  air-  into 
the  stomach.  M.  Gosse,  of  Geneva,  had  acquired  that  power  from  re- 
peated experience,  and  he  made  use  of  it  to  induce  vomiting  at  pleasure, 
and  by  the  application  of  that  faculty  to  the  interests  of  science,  he  as- 
certained the  digestibility  of  the  articles  of  food  in  most  common  use. 

-The  food  descends  into  the  oesophagus,  propelled  by  the  contractions 
of  that  musculo-membranous  duct,  situated  along  the  vertebral  column, 
from  the  pharynx  to  the  stomach.  Mucus  is  secreted,  in  considerable 
quantity,  by  the  membrane  which  lines  the  inner  part  of  the  oesophagus, 
it  sheathes  the  substances  which  pass  along  it,  and  renders  their  passage 
more  free.  The  longitudinal  folds  of  their  inner  membrane,  allow  the 
oesophagus  to  dilate  ;  nevertheless,  when  it  is  stretched  beyond  measure, 
severe  pain  is  experienced,  occasioned,  no  doubt,  by  thedistention  of  the 
nervous  plexuses,  formed  by  the  nerves  of  the  eighth  pair,  which  embrace 
the  oesophagus,  as  they  course  along  its  sides — I  purposely  avoid  speak- 

*  Hydrophobia,  presents  us  with  the  most  distressing  examples  of  this  kind  The 
very  sight  or  sound  of  fluids  produce  dreadful  spasms  of  the  muscles  of  deglutition  ; 
sometimes,  even  speaking  of  fluids  has  the  same  effect.  Dr.  Fothergill's  case,  pub- 
lished in  the  London  Medical  Observations  and  Inquiries,  may  be  particularly  referred 
to,  as  the  patient  throughout  had  not  the  slightest  suspicion  of  the  nature  cf  his  disease, 
and  the  dread  could  not  have  beeai  imaginary. — Godman. 


86 

ing  of  the  weight  of  the  food,  as  one  of  the  causes  which  enable  it  to  pass 
along  the  oesophagus*.  Although,  in  man  as  in  quadrupeds,  that  weight 
is  no  object  to  deglutition,  it  favours  that  function  in  so  slight  a  degree, 
that  the  diminution  of  muscular  contractility  at  the  approach  of  death, 
is  sufficient  altogether  to  prevent  it.  The  act  of  drinking  is  then  attend- 
ed with  a  noise  of 'unfavourable  omen.  This  noise  consists  in  a  gurgling 
of  the  fluid  which  has  a  tendency  to  get  into  the  larynx,  whose  opening 
is  not  covered  ever  by  the  epiglottis;  and  if  it  be  insisted  upon,  that  the 
patient  shall  swallow  some  pitsan,  tfce  deglutition  of  which  is  impractic- 
able, it  flows  into  the  trachea,  and  the  patient  dies  of  suffocation. 

XIII.  Of  the  Jlbdoimn\.  Before  inquiring  any  farther  into  the  pheno- 
mena of  digestion,  let  us  shortly  attend  to  the  cavity  which  contains  its 
principal  organs.  The  abdomen  is  almost  entirely  filled  by  the  digestive 
apparatus,  of  which  the  urinary  passages  form  a  part:  its  size,  the  struc- 
ture of  its  parietes,  are  evidently  adapted  to  the  functions  of  that  appara- 
tus. The  capacity  of  the  abdomen,  exceeds  that  of  the  other  two  great 
cavities;  its  dimensions  are  not  invariably  fixed,  as  those  of  the  skull, 
whose  size  is  determined  by  the  extent  of  its  osseous  and  inelastic  pari- 
etes. They  are  likewise  more  varying  than  those  of  the  chest,  because 
the  degree  of  dilatation,  of  which  the  latter  is  susceptible,  is  limited  by 
the  extent  of  motion,  of  which  the  ribs  and  sternum  are  capable.  The 
abdomen,  on  the  contrary,  enlarges  in  a  sort  of  indefinite  mariner,  by  the 
yielding  of  its  soft  and  extensible  parietes.  In  some  cases  of  ascites,  the 
abdomen  has  been  known  to  contain  as  much  as  eighty  pints  of  liquid, 
and  yet  death  has  not  followed  as  a  consequence  of  so  enormous  an  accu- 
mulation; while  in  consequence  of  the  delicate  texture  of  the  brain,  of 
the  exact  fulness  of  the  skull,  and  especially  of  the  inflexibility  of  its  pa- 
rietes, the  slightest  effusions  within  that  cavity  are  attended  with  so  much 
danger;  while  the  collection  of  a  few  pints  of  fluid,  within  the  chest,  oc- 
casions suffocation.  This  vast  capacity  of  the  abdomen,  capable  of  being 
easily  increased,  was  required  in  a  cavity  whose  viscera,  for  the  most  part 
hollow,  and  admitting  of  dilatation,  contain  substances  varying  in  quanti- 
ty, and  from  which  are  disengaged  gases  occupying  a  considerable 
space.  What  a  difference  is  there  not,  in  the  capacity  of  the  abdomen 
of  animals,  according  to  the  quality  of  the  food  on  which  they  feed] 

*  A  very  curious  instance  of  deglutition  may  be  seen  in  the  Java  bat ;  vespertilio  vam- 
pi/rns,  ofLinnsus.  The  specimen  of  this  animal,  lately  living- in  the  Philadelphia  Mu- 
seum, was  continually  pendent,  by  the  hooks  of  one  or  both  leg's.  In  this  situation  it 
took  food,  which,  when  masticated,  was  forced,  by  a  peculiar  muscular  movement,  to 
ascend  perpendicularly  to  the  stomach. —  Godman. 

•}-  It  is  requisite,  in  physiology,  as  well  as  in  medical  practice,  to  have  an  artificial  di- 
vision of  the  abdominal  cavity,  in  order  to  point  out  the  exact  and  relative  situations  of 
the  viscera  which  it  contains.  With  this  view,  it  has  been  usually  divided  into  three 
regions,  called  the  upper,  middle,  and  under  region  :  each  of  these  is  subdivided  into  three 
others.  The  UPPKH  region  begins  at  the  ensiform  cartilage,  and  extends  downwards  to 
about  four  inches  from  the  umbilicus ;  the  middle  of  it  is  termed  the  epigastrium^  and 
the  t\vo  lateral  portions  hypochondria,  from  their  situation  under  the  cartilages,  of  the. 
false  ribs. 

The  MIDDLE  region  occupies  about  four  inches  above  and  below  the  umbilicus.  Its 
middle  portion  is  called  the  umbilieul,  uncl  its  lateral  parts  the  loins  or  lumbar  regions. 
The  TI.VDER  division  of  the  abdominal  cavity  commences  where  the  former  one  termi- 
nates, or  at  a  line  drawn  between  the  superior  and  anterior  spinous  process  of  the  ossa 
ilii,  and  forms,  in  the  middle,  the  hupogaatrium,  or  bottom  of  the  belly ;  and  at  the  sides, 
the  iliac  regions. —  Copland. 


Compare  the  slender  body  of  the  tyger,  of  the  leopard,  and  of  all  carni- 
vorous animals,  with  the  heavy  mass  of  the  elephant,  of  the  ox,  and  of 
all  animals,  that  wholly  or  principally  live  on  animal  food.  In  the  child, 
who,  for  his  growth  and  clevelopement,  digests  a  considerable  quantity  of 
food,  the  abdomen  is  much  more  capacious  than  in  the  adult,  or  the  old 
man.  In  the  child,  the  ensiform  cartilage  is  situated  opposite  to  the 
body  of  the  eigth  or  ninth  dorsal  vertebra.  In  old  men,  it  descends  to 
the  tenth  or  even  the  eleventh,  so  that  the  capacity  of  the  abdomen  de- 
creases with  the  want  of  food,  and  with  the  activity  of  digestion. 

The  internal  organs  of  the  body  are  incessantly  called  into  action  by 
different  causes,  and  excited  to  different  motions*.  The  action  of  the  ar- 
terial system  tends  to  raise  the  cerebral  mass,  and  to  impart  to  it  mo- 
tions of  elevation  and  depression.  The  motion  of  the  ribs  brings  about 
the  expansion  and  the  compression  of  the  pulmonary  tissue;  the  heart, 
which  adheres  to  the  diaphragm,  drawn  down  by  that  muscle,  when  it 
descends,  strikes  against,  the  parietes  of  the  chest,  every  time  its  ventri- 
cles contract.  The  abdominal  viscera  are  not  less  agitated  by  the  mo- 
tions of  respiration,  they  experience  from  the  diaphragm  and  from  the 
abdominal  muscles  a  perpetual  action  and  re-action,  by  means  of  which, 
the  circulation  of  the  fluids  in  their  vessels  is  promoted,  the  course  of 
the  food  in  the  alimentary  canal  is  accelerated,  the  activity  of  digestion 
increased,  and  several  excretions,  as  of  the  urine  and  fseces,  performed. 

XIV.  Of  Digestion  in  the  Stomach^.  The  food  which  is  taken  into  the 
stomajch  accumulates  gradually  within  its  cavity,  and  separates  its  pari- 
etes, which  are  always  in  contact  with  each  other  when  it  is  empty.  The 
stomach,  in  that  mechanical  distention  by  the  food,  yields  without  re- 
acting. It  is  not,  however,  absolutely  passive;  its  parietes  apply  them- 
selves, by  a  general  contraction,  by  a  kind  of  tonic  motion  to  the  food 
which  lies  within  it,  and  to  this  action  of  the  whole  stomach,  the  ancients 
gave  the  name  of  peristok\.  As  the  stomach  dilates,  its  great  curvature 
is  thurst  forward,  the  two  folds  of  the  omentum  recede  from  each  other, 
receive  it  between  them,  and  embrace  its  outer  and  dilated  part.  In 
man,  the  principal  use  of  this  fold  of  the  peritoneum,  appears  to  be  to 
facilitate  the  dilatation  of  the  stomach,  which  expands  chiefly  at  its  fore- 
part, as  may  be  observed  by  inflating  it  in  a  dead  body.  As  this  viscus 
becomes  distended  with  air,  the  two  folds  of  the  omentum  apply  them- 
selves to  its  surface,  and  if  this  membrane  is  pierced  with  a  pin,  at  the 
distance  of  an  inch  from  its  great  curvature,  the  pin  is  observed  to  get 
nearer  to  this  curvature;  but  the  .upper  portion  of  the  omentum  can 
alone  be  employed  in  this  use,  and  the  whole  of  this  membranous  fold  is 
never  entirely  occupied  by  the  stomach.  Shall  we  say  with  Galen,  that 

*  Before  the  skull  is  ossified,  or  after  parts  of  the  scullcap  have  been  removed.  When 
the  bone  is  entire,  we  have  no  reason  to  believe,  that  there  is  the  slightest  elevation  or 
depression  of  the  brain. — Godman. 

f  See  APPENDIX,  Note  K. 

*  In  order  to  explain  correctly  the  functions  of  the  stomach  either  in  their  healthy 
or  disordered  state,  the  conformation  of  the  muscular  coat  requires  to  be  pointed  out. 
This  tunic  is  composed  of  three  strata  ;  the^rrf,  or  the  exterior,  consists  of  longitudi- 
nal fibres,  proceeding  from  the  oesophagus  along  the  axis  of  the  stomach  and  continued 
to  the  duodenum  ;  the  second,  or  middle  stratum,  which  is  the  thickest,  is  composed  of 
fibres  that  have  an  oblique  direction,  and  which,  surrounding  the  stomach,  decussate 
one  another ;  the  third,  or  interior  stratum,  consists  entirely  of  circular  fibres,  which  ex- 
tend from  one  curvature  of  this  viscus  to  the  other Copland. 


88 

the  omentum  guards  the  intestines  against  cold,  and  preserves  in  them  a 
gentle  warmth,  necessary  to  digestion  ;  or  shall  we  admit  the  opinion  ot" 
those  who  maintain,  that  it  answers  the  purpose  of  a  fluid,  filling  up 
spaces,  and  lessening  the  effect  of  friction  and  pressure  from  the  anterior 
parietes  of  the  abdomen  ;  or  shall  we  assert  with  others,  that  the  use  of 
the  omentum  is  to  allow  the  blood  to  flow  into  it,  when  the  stomach,  in 
a  state  of  contraction,  is  incapable  of  receiving  it.  May  not  the^blood 
which  flows  so  slowly  in  its  long  and  slender  vessels,  acquire  some  olea- 
ginous quality  which  renders  it  filter  to  supply  the  materials  of  bile*? 

The  stomach  likewise  stretches,  though  in  a  less  distinct  manner, 
towards  its  lesser  curvature,  and  the  laminse  of  the  gastro-hepatic 
omentum  are  separated  from  each  other,  as  those  of  the  omentum 
majus.  ^  Such  is  the  utility  of  the  gastro-hepatic  omentum,  which  may 
be  considered  as  a  necessary  result  of  the  manner  in  which  the  peritoneum 
is  disposed  in  relation  to  the  viscera  of  the  abdomen.  This  membrane, 
which  extends  from  the  stomach  to  the  liver,  so  as  to  cover  it,  could  not 
fill  the  space  which  separates  those  organs,  were  it  not  for  a  kind  of 
membranous  communication  which  connects  them,  ami  in  which  are  con- 
tained the  vessels  and  nerves,  which,  fro  pi  the  lesser  curvature,  or  the 
posterior  edge  of  the  stomach,  course  towards  the  concave  surface  of  the 
liver.  This  gastro-hepatic  epiploon,  may  besides,  by  the  separation  of 
the  t\Vo  laminae  of  which  it  is  formed,  favour  the  dilation  of  the  hepatic 
vein,  which  is  situated,  as  well  as  the  vessels,  the  nerves,  and  the  excre- 
tory ducts  of  the  liver,  in  the  thickness  of  its  right  border. 

The  stomach  has  ever  been  considered  as  the  principal  organ  of  diges- 
tion, yet  its  function  in  that  process  is  but  secondary  and  preparatory;  it 
is  not  in  the  stomach  that  the  principal  and  most  essential  phenomenon 
of  digestion  takes  place,  I  mean  the  separation  of  the  nutritive  from  the 
excrementitious  part  of  the  food.  The  food,  when  received  into  the 
stomach,  is  prepared  for  this  separation  which  is  soon  to  be  performed, 
it  becomes  fluid,  and  undergoes  a  material  alteration ;  it  is  converted  into 
a  soft  and  homogeneous  paste,  known  under  the  name  of  chyme.  What 
is  the  agent  that  brings  about  this  change?  or  in  other  words,  in  what 
does  digestion  in  the  stomach  consist? 

As  it  is  frequently  necessary  to  clear  a  spot  on  which  one  means  to 
build,  we  will  bring  forward  and  refute  the  hypotheses  that  have  been 
successively  broached,  to  explain  the  mechanism  of  digestion.  They 
may  be  enumerated  as  follows : — concoction,  fermentation,  putrefaction, 
trituration,  and  maceration  of  the  food  taken  into  the  cavity  of  the 
stomach. 

XV.  The  first  of  these  opinions  was  that  of  the  ancients  and  of  the  fa- 
ther of  physic ;  but,  by  the  term  concoction,  Hippocrates  did  not  mean 
a  phenomenon  similar  to  that  which  takes  place,  when  food  is  put  into  a 
vessel,  and  exposed  to  the  influence  of  heat.  The  temperature  of  the 


*  The  omentum  seems  to  lubricate  the  intestines  by  means  of  its  adipose  halitus, 
and  to  aid  in  facilitating  the  continual  movements  of  the  intestines.  It  also  appears  to 
assist  in  the  reciprocal  motion  which  takes  place  between  the  digestive  tube  and  the 
anterior  abdominal  parietes,  especially  in  preventing  the  natural  and  increased  action 
of  the  latter,  during  respiration  and  muscular  exertion,  from  impeding  or  injuring  the 
function  of  the  former.  It  likewise  obviates  the  adhesion  of  the  intestines  to  the  peri- 
toneum during  disease,  and  the  consequent  impediment  to  the  operations  of  the 
primse  vise.—  Copland. 


89 

stomach,  which  does  not  exceed  that  of  the  rest  of  the  body,  (32  degrees 
of  Reaumur's  scale)  would  be  insufficient.  Cold-blooded  animals  digest 
equally  with  the  warm-blooded,  and,  as  Vanhelmont  observes,  febrile 
heat  impairs,  instead  of  increasing  the  powers  of  digestion.  In  the  lan- 
guage of  the  ancients,  concoction  means  the  alteration,  the  maturation, 
the  animalizationof  alimentary  substances,  assimilated  to  our  nature,  by 
the  changes  which  they  undergo  in  the  cavity  of  the  stomach.  It  is,  how- 
ever, a  verified  fact,  that  the  natural  heat  of  the  stomach  promotes  and 
facilitates  those  changes.  The  experiments  of  Spallanzani  on  artificial 
digestion,  show,  that  the  gastric  juice  is  not  of  more  efficacy  than  plain 
water,  in  softening  and  dissolving  alimentary  substances,  when  the  heat 
is  below  seven  degrees  (of  Reaumur's  scale;)  that  its  activity,  on  the  con- 
trary, is  greatly  increased  when  the  heat  is  ten,  twenty,  thirty,  or  forty 
degrees  above  the  freezing  point.  The  digestion  in  the  cold-blooded  ani- 
mals is,  besides,  slower  than  in  the  hot-blooded. 

XVI.  The  abettors  of  the  theory  of  fermentation  admit  that  the  food 
taken  into  the  stomach  undergoes  an  inward  and  spontaneous  motion,  in 
virtue  of  which  it  forms  new  combinations;  and  as  the  process  of  fer- 
mentation is  promoted,  by  adding,  to  the  substance  th-at  is  undergoing 
that  change,  a  certain  quantity  of  the  same  that  has  already  undergone 
the  process ;  some  have  supposed  that  there   continually  exists  in  the 
stomach   a  leaven,  formed,  according  to  Vanhelmont,   by  a  subtle  acid, 
and  consisting,  in  the  opinion  of  others,  of  a  small  quantity  of  the  food 
that  remains  from  the  former  digestion.     But,  independently  of  the  cir- 
cumstance that  the  stomach  empties  itself  completely,  and  presents  no 
appearance  of  leaven,  when  examined  a  few  hours  after  digestion,  sub- 
stances undergoing  fermentation  require  to   be  kept  perfectly   at  rest, 
whereas  the  food  is  exposed  to  the  oscillatory  circulations  and  to  the  pe- 
ristaltic contractions  of  the  stomach,  and  this  viscus  is  shaken  by  the 
pulsations  of  the  neighbouring  arteries;  it  is  besides  kept  in  continual 
motion  by  the  act  of  respiration.     In  fermentation  gases  are  either  ab- 
sorbed or  extricated,  neither  of  which  circumstances  takes  place  when 
the  stomach  is  not  out  of  order. 

It  should,  however,  be  stated,  in  support  of  the  opinion  that  accounts 
for  digestion  on  the  principle  of  fermentation,  that  we  can  derive  nourish- 
ment, only  from  substances  capable  of  undergoing  fermentation,  and  that 
the  substances  which  have  undergone  the  panaryand  saccharine  fermen- 
tation are  more  easily  digested,  and  in  less  time.  This  imperceptible 
fermentation,  if  it  really  take  place,  must  bear  a  greater  analogy  to  these 
two  last  processes,  to  those  which  are  called  vinous  and  acetous  fer- 
mentation: but  no  one  can  differ  from  it  more  than  the  putrid  fermen- 
tation. 

XVII.  There  have  been  physiologists,  however,  from  the  time  ofPlis- 
tonicus,  the  disciple  of  Pruxagoras,  who  maintain,  that  digestion  is,  in 
fact,  the  consequence  of  putrefaction.   But,  not  only  is  ammonia  not  dis- 
engaged during  that  process,  but  our  digestive  organs  have  the  power, 
as  will  be  seen  presently,  of  retarding,  or  of  suspending,  the  putrefaction 
of  the  substances  which  are  submitted   to  their  action.     In  serpents, 
which  in  consequence  of  the  great  power  of  dilatation  of  the  oesophagus, 
and  from  the  power  of  holding  asunder  their  jaws,  both  of  which  are 
moveable  nearly  in  an  equal  degree,  frequently  swallow  larger  animals 
than  themselves,  and  take  several  days  to  digest  them;  that  part  of  the 
animal  which  is  exposed  to  the  action  of  the  stomach,  is  observed  to  be 

M 


90 

perfectly  fresh,  and  dissolved  to  a  certain  extent,  while  the  part  which 
remains  out,  exhibits  signs  of  incipient  putrefaction,  In  fine,  notwith- 
standing the  heat  and  moisture  of  the  stomach,  the  food  does  not  remain 
in  it  long-  enough,  to  allow  putrefaction  to  come  on,  even  though  every 
thing  else  should  favour  that  process.  Animals  which  have  by  chance 
swallowed  putrescent  animal  substances,  either  reject  them  by  vomiting, 
or,  as  Spallanzani  has  observed  in  some  birds,  deprive  them  of  their 
putridity. 

XVIII.  Tine  system  of  fermentation  was  invented  by  the  chemists; 
that  of  trituration,  by  the  mechanical  philosophers,  who  compare  the 
changes  which  substances  undergo  in  a  mortar  from  the  action  of  the 
pestle,  to  the  changes  which  the  food  undergoes  in  the  stomach.  But  how 
different  is  the  triturating  action  of  a  pestle,  which  crushes  a  substance 
softer  than  itself  against  a  resisting  surface,  to  the  gentle  and  peristaltic 
action  of  the  fibres  of  the  stomach,  on  the  substances  which  it  contains. 
Trituration,  which  is  a  mechanical  effect,  does  not  alter  the  nature  of  the 
substance  exposed  to  its  action;  but  the  food  is  decomposed,  and  no 
longer  the  same  substance,  after  it  has  remained  some  time  in  the  sto- 
mach. As  this  evidently  absurd  hypothesis  has  long  been  heid  in  high 
estimation,  it  will  not  be  improper  to  spend  a  little  time  in  the  refutation 
of  the  proofs  which  are  adduced  in  its  support. 

The  manner  in  which  digestion  is  brought  about  in  birds,  whose  sto- 
mach is  muscular,  and  especially  in  the  gallinaceous  fowls,  is  the  most 
specious  argument  adduced  by  the  abettors  of  mechanical  digestion. 
Those  granivorous  birds  all  have  a  double  stomach,  the  first  is  culled  the 
crop,  its  sides  are  thin  and  almost  entirely  membranous;  a  fluid  is  abun- 
dantly effused  on  its  inner  surface,  the  seeds  on  which  they  feed  get 
softened,  and  undergo  a  kind  of  preliminary  maceration  in  the  crop,  after 
which  they  are  more  easily  ground  by  the  gizzard,  which  is  a  truly  mus- 
cular stomach,  that  fulfils  the  office  of  organs  of  mastication,  almost  en- 
tirely deficient  in  that  class  of  animals.  The  gizzard  acts  so  powerfully, 
that  it  crushes  the  solid  substances  exposed  to  its  action,  reduces  into 
dust  balls  of  glass  and  crystal,  flattens  tubes  of  tin,  breaks  pieces  of  me- 
tal, and  what  is  much  more  extraordinary,  breaks  with  impunity  the 
points  of  the  sharpest  needles  and  lancets.  Its  internal  partis  lined  with 
a  thick  semicartilaginous  membrane,  incrusted  with  a  number  of  small 
stones  and  gravel,  taken  in  with  the  food  of  those  birds.  The  turkey  cock 
is,  of  all  other  fowls,  that  in  which  this  structure  is  most  apparent ;  be- 
sides the  small  pebbles  which  line  its  inner  membrane,  its  cavity  contains, 
almost  in  all  cases,  a  number  of  them.  The  rubbing  together  of  these 
hard  substances,  exposed  along  with  the  seeds  among  which  they  are 
mixed,  to  the  action  of  the  stomach,  may  assist  in  breaking  them  down. 
The  pieces  of  iron  and  the  pebbles  which  the  ostrich  swallows,  some  of 
which  Valisnieri  met  with'  in  the  stomach  of  that  bird,  are  destined  to 
the  same  use.  But  this  mechanical  division  which  the  gizzard  performs 
in  the  absence  of  organs  of  mastication,  does  not  constitute  digestion;  the 
food  softened  and  divided  by  the  action  of  the  crop  and  of  the  gizzard, 
passes  into  the  duodenum,  and  exposed  in  that  intestine  to  the  action  of 
the  biliary  juices,  undergoes  within  it  the  changes  most  essential  to  the 
act  of  digestion. 

The  singular  structure  of  the  lobster's  stomach  is  not  more  favourable 
to  the  hypothesis  of  trituration.  In  that  crustaceous  animal,  the  stomach 
is  furnished  with  a  real  mandibular  apparatus,  destined  to  break  down 


91 

the  food.  There  are  found  in  it,  besides,  at  certain  times  of  the  year, 
two  roundish  concretions,  on  each  side,  under  its  internal  membrane. 
These  concretions,  improperly  termed  crabs'  eyes,  consist  of  carbonate 
of  lime  joined  to  a  small  quantity  of  gelatinous  animal  matter;  they  dis- 
appear, when,  after  the  annual  shedding  of  the  shell,  the  external  cover- 
ing, at  first  membranous,  becomes  solid  from  the  deposition  of  the  calca- 
reous matter  of  which  they  are  formed. 

The  very  great  difference  between  the  stomach  of  these  animals  and 
that  of  man,  ought  to  have  precluded  every  idea  of  comparing  them  toge- 
ther. Spallanzani  has  justly  observed,  that  in  regard  to  the  muscular 
power  of  the  parietes  of  the  stomach,  animals  might  be  divided  into  three 
classes,  the  most  numerous  of  which  consists  of  those  creatures,  whose 
stomach  is  almost  entirely  membranous,  and  furnished  with  a  muscular 
coat  of  very  little  thickness.  In  thi§  class  are  contained,  man,  quadru- 
peds, birds  of  prey,  reptiles,  and  fishes.  Notwithstanding  the  weakness 
of  that  muscular  coat,  Pitcairn,  by  a  misapplied  calculation,  has  estimated 
its  power  at  12,951  pounds;  he  reckons  at  248,335  pounds,  that  of  the 
diaphragm  and  of  the  abdominal  muscles  which  act  on  the  stomach,  and 
compress  it  in  the  alternate  motions  of  respiration.  What  does  so  exag- 
gerated a  calculation  prove,  except,  as  Garat  observes,  that  this  vain 
show  of  axioms,  definitions,  scholia,  and  corollaries,  with  which  works 
not  belonging  to  mathematics  have  been  disfigured,  have  served  only  to 
protect  vague,  confused,  and  false  notions,  under  the  cover  of  imposing 
and  respected  forms.  One  need  only  introduce  one's  hand  into  the  abdo- 
men of  a  living  animal,  or  a  finger  into  a  wound  of  the  stomach,  to  as- 
certain that  the  force  of  that  viscus  on  its  contents,  does  not  exceed  a 
few  ounces. 

XIX.  The  learned  and  indefatigable  Haller  thought,  that  the  food  was 
merely  softened  and  diluted  by  the  gastric  juice.  This  maceration  was, 
in  his  opinion,  promoted  and  accelerated  by  the  warmth  of  the  part,  by 
the  incipient  putrefaction,  by  the  gentle  bui  continual  motions  which  the 
alimentary  substance  undergoes.  Maceration,  in  time,  overcomes  the 
force  of  cohesion  of  the  most  solid  substances ;  but  by  dilution  it  never 
changes  their  nature. — Haller  rested  on  the  experiments  of  Albinus, 
on  the  conversion  of  membranous  tissues  into  mucilage,  by  protracted 
maceration. 

In  ruminating  animals,  the  cavity  of  the  stomach  is  divided  into  four 
parts,  which  open  into  one  another,  and  of  which  the  three  first  commu- 
nicate with  the  oesophagus.  When  the  grass,  after  imperfect  trituratiou 
by  the  organs  of  mastication,  whose  power  is  inconsiderable,  has  reached 
the  paunch,  which  is  the  first  and  largest  of  the  four  stomachs,  it  under- 
goes a  real  maceration,  together  with  an  incipient  acid  fermentation. — 
The  contractions  of  the  stomach  propel  the  food,  in  small  quantities  at  a 
time,  into  the  bonnet,  which  is  smaller  and  more  muscular  than  the 
paunch;  it  coils  on  itself,  covers  with  mucus  the  already  softened  food, 
then  forms  it  into  a  ball,  which  rises  into  the  mouth,  by  a  truly  antiperi- 
staltic  motion  of  the  oesophagus.  The  alimentary  bolus,  after  having 
been  chewed  over  again  by  the  animal,  which  seems  to  enjoy  that  pro- 
cess, descends  along  the  oesophagus  into  the  third  stomach,  called  the 
manyplus,  on  account  of  the  large  and  numerous  folds  of  its  inner  mem- 
brane. From  this  cavity  the  food  enters  into  the  abomasum,  in  which 
the  stomachic  digestion  is  completed.  Such  is  the  mechanism  of  rumi- 
nation, a  function  peculiar  to  animals  that  have  four  stomachs:  they  do 


not,  however,  ruminate  at  all  periods  of  their  life.  The  sucking  lamb 
does  not  ruminate  :  the  half  digested  milk  does  not  pass  along  the  paunch 
or  the  bonnet,  which  are  useless,  but  at  once  descends  into  the  third 
stomach*.  Some  men  have  been  capable  of  a  kind  of  rumination;  the 
alimentary  ball,  after  descending  into  the  stomach,  shortly  alter  rose  in- 
to the  mouth,  to  be  there  chewed  a  second  time,  and  to  be  anew  imbued 
with  saliva.  Conrad  Peyer  has  made  this  morbid  phenomenon  the  sub- 
ject of  a  dissertation,  entitled  Mericologia,  sine  fa  t&r-inantibm\. 

This  fourfold  division  of  the  stomach,  so  favourable  to  Mailer's  theory, 
is  observed  only  in  ruminating'  animals.  But  though  animal*  are  in  ge- 
neral monogastric,  as  map?  that  is,  provided  with  only  one  stomach,  this 
viscus  offers  a  number  of  varieties,  the  most  remarkable  of  which  refer 
to  the  relative  facility  which  the  food  meets,  in  remaining  within  its  ca- 
vity. The  insertion  of  the  oesophagus  is  nearer  to  its  left  extremity,  and 
the  great  fundus  of  that  viscus  is  smaller,  as  animals  feed  more  exclusive- 
ly on  flesh,  which  is  a  substance  of  remarkably  easy  decomposition,  and 
not  requiring  for  its  digestion  a  long  stay  in  the  stomach.  In  herbivo- 
rous quadrupeds,  which  do  not  ruminate,  this  great  fundus  forms  nearly 
one  half,  sometimes  even  the  greater  part  of  the  stomach,  as  the  oesopha- 
gus enters  into  it  very  near  the  pylorus.  In  some,  as  in  the  hog,  the  sto- 
mach is  divided  into  two  parts  by  a  circular  contraction.  The  food 
which  is  received  into  the  great  fundus  of  the  stomach,  may  remain 
longer  in  that  viscus,  as  this  part  of  its  cavity  lies  out  of  the  course  of 
the  aliment. 

XX.  Of  the  Gastric  Juice.  Of  all  the  organs,  the  stomach  probably  re- 
ceives, in  proportion  to  its  bulk,  the  greatest  number  of  blood-vessels  j 
in  its  membrane-muscular  parietes,  which  are  little  more  than  the  twelfth 
part  of  an  inch  in  thickness,  there  is  distributed  the  coronary  artery  of 
the  stomach,  entirely  destined  to  that  organ  ,  the  pyloric,  the  right 
gastro-epiploic,  given  off  by  the  hepatic  artery.  The  greater  part  of  the 
blood,  therefore,  which  passes  from  the  aorta  to  the.  cseliac  artery  goes  to 
the  stomach,  for  thougr11  ot  tne  arteries  into  which  that  trunk  is  divided, 
the  coronary  of  tne  stomach  is  the  least,  the  arteries  of  the  liver  and 
spleen  send  to  the  stomach  several  pretty  considerable  blanches,  before 
entering  the  viscera  to  which  they  are  more  particularly  allotted.  One 
need  only  observe  the  great  disproportion  between  the  stomach  and  the 
quantity  of  blood  which  it  receives,  to  conclude,  that  this  fluid  is  not 
merely  subservient  to  its  nutrition,  but  is  destined  to  furnish  the  materi- 
als of  some  secretion. 

The  secretion  in  question,  is  that  of  the  gastric  juice,  which  is  most 
abundantly  supplied  by  arterial  exhalation,  from  the  internal  surface  of 
the  stomach  ;  it  is  most  active  at  the  instant  when  the  food  received  \ 
within  its  cavity,  excites  irritation,  transforms  it  into  a  centre  of  fluxion^ 
towards  which  the  fluids  flow  from  all  directions.  The  state  of  fulness 
of  the  stomach,  favours  the  afflux  of  the  fluids  into  the  vessels,  as,  in  con- 
sequence of  the  extension  of  its  parietes  previously  collapsed,  the  vessels 
are  no  longer  bent  and  creased.  The  arteries  of  the  stomach,  of  the 
spleen  and  liver,  arising  from  a  common  trunk,  it  may  be  easily  under- 


*  Seethe  Journal  of  Foreign  Medicine  published  in  Philadelphia*  No.  4,  p.  472".. — 
Godman. 
|  See  APPENDIX,  Note  K. 


stood  how,  \frhen  the  stomach  is  empty,  little  biood  enters  into  it,  in  that 
state  of  contraction  ;  how  at  the  same  time,  the  spleen  which  is  less  com- 
pressed, and  the  liver,  must  receive  a  larger  supply  of  blood,  and  again  a 
smaller  quantity,  when  the  stomach  is  full. 

The  gastric  juice,  the  result  of  arterial  exhalation,  mixes  with  the  mu- 
cus poured  out  by  the  mucous  follicles  of  the  internal  membrane  of  the 
stomach.  This  mixture  renders  it  viscous  and  ropy,  like  the  saliva,  to 
which,  in  man,  the  gastric  juice  bears  a-great  analogy.  It  is  very  difficult 
to  obtain  it  pure,  so  as  to  analyze  it,  and  even  if  by  long  fasting,  the  sto- 
mach should  be  deprived  of  the  alimentary  residue,  which  might  affect  its 
purity,  (5ne  could  not  prevent  its  being  mixed  with  a  certain  quantity  of 
liquid  bile,  which  always  flows  back  through  the  pyloric  orifice,  turns 
yellow  the  inner  surface  of  the  stomach,  in  the  neighbourhood  of  that 
orifice,  and  even  imparts  a  certain  degree  of  bitterness  to  the  gastric 
juice.  The  passage  of  the  bile  from  the  duodenum  into  the  stomach,  can- 
not be  looked  upon  as  morbid;  it  occurs  in  the  most  perfect  health, 
which  has  led  to  a  well  founded  opinion,  that  a  small  quantity  of  the  bili- 
ary fluid  is  a  useful  stimulus  to  the  stomach.  This  opinion  is  confirmed 
by  an  observation  of  Vesalius,  who  relates,  that  he  found  the  ductus 
communis  choledochus,  opening  into  the  stomach,  in  the  body  of  a  con- 
vict noted  for  his  voracious  appetite.  It  is  further  confirmed  by  what  is. 
observed  in  birds  of  prey,  in  the  pike,  Sec.  who  digest  easily  and  with 
great  rapidity,  because  the  termination  into  the  duodenum  of  the  ductus 
communis  choledochus,  being  very  near  to  the  pylorus,  the  biie  easily 
ascends  into  the  stomach,  and  is  always  found  there  in  considerable 
quantity. 

To  obtain  some  of  this  gastric  juice,  it  is  necessary,  either  to  open  a 
living  animal  under  the  influence  of  hunger,  or  to  oblige  a  night  bird  of 
prey,  as  an  owl,  to  swallow  small  spunges  fastened  to  a  long  thrend. 
When  the  spunge  has  remained  for  a  s  >ort  time  in  the  stomach,  it  is 
withdrawn  soaked  with  gastric  juice,  of  which  the  secretion  has  been  pro- 
moted by  its  presence  in  the  stomach. 

The  gastric  juice,  in  its  natural  state,  is  neither  acid  nor  alkaline  :  it 
does  not  turn  red  or  green,  vegetable  blue  colours*.  Its  most  remarka- 
ble quality  is,  its  singularly  powerful  solvent  faculty,  the  hardest  bones 
cannot  withstand  its  action;  it  acts  on  those  on  which  the  dog  feeds;  it 
combines  with  all  their  organized  and  gelatinous  parts,  reduced  them  to 
a  calcareous  residue,  forming  those  excrementitious  substances  so  ab- 
surdly called  album  graseujn,  by  the  older  chemists.  The  solvent  energy 
of  the  gastric  juice,  is  in  inverse  ratio  of  the  muscular  strength  of  the 

*  There  is  some  difference  of  opinion  on  this  point.  Carminati  declares  that  in  car- 
nivorous animals  the  gastric  fluid  is  add,  that  in  phytivorous  it  is  alkaline,  and  that  in 
those  which  live  indiscriminately  on  animal  and  vegetable  food,  it  is  neither  acid  nor 
alkaline.  By  BrugnatelU  it  is  said  that,  in  all  animals,  it  is  uniformly  acid.  That  the 
gastric  hquor  is  occasionally  acid  in  the  human  species,  cannot  be  denied.  It  has  in- 
deed been  found  so  both  by  Reaumur  and  Hunter,  and  in  subjects  where  there  was  no 
reason  to  presume  it  had  become  vitiated  by  a  disordered  condition  of  the  stomach. 

We  are  inclined  to  believe  that  the  gastric  fluid  has  pretty  nearly  the  same  proper- 
ties in  all  animals.  In  support  of  this  conclusion  we  may  appeal  to"  the  fact  which  has 
been  verified  by  repeated  experiments,  that  both  carnivorous  and  phytivorous  animals 
digest  and  thrive  well  on  an  exchange  of  food,  the  one  being-  made  to  feed  exclusively 
on  vegetable,  and  the  other  on  animal  matter.  Vide  Experiments  of  J.  Hunter  and 
Spallanzam. — Chapman. 


94 

parietes  of  the  stomach,  and  in  those  animals  in  which  the  parietes  of 
that  viscus  arc  very  thin,  and  almost  entirely  membranous,  it  has  most 
power  and  activity.  In  the  numerous  class  of  zoophytes,  it  alone  suffices 
to  effect  decomposition  of  the  food,  always  more  prompt,  when  accom- 
panied by  warmth  of  the  atmosphere,  as  \vas  observed  by  du  Trembly,  in 
the  polypi,  which  in  summer,  dissolve  in  twelve  hours,  what  in  colder 
weather  it  would  take  three  days  to  digest.  In  the  actinia,  in  the  holo- 
thuda,  the  gastric  juice  destroys  even  the  shells  of  the  muscles  which 
they  swallow.  Are  we  not  all  acquainted  with  the  peculiar  flavour  of 
oysters,  how  much  they  tend  to  whet  the  appetite  ?  this  sensation  de- 
pends less  on  the  salt  water  contained  in  the  shell,  than  on  the'  gastric 
juice  which  acts  on  the  tongue,  which  softens  its  tissue,  and  quickens  its 
sensibility*.  This  mucous  substance,  when  received  into  the  stomach, 
promotes  the  digestion  of  the  food  which  is  afterwards  taken  into  it,  for 
the  oyster  itself  is  very  little  nutritious,  and  is  used  rather  as  a  condi- 
ment, than  as  affording  nourishment. 

The  gastric  juice  not  only  pervades  and  dissolves  the  food  received  in- 
to the  stomach,  but  it  unites  and  intimately  combines  with  it,  completely 
alters  its  nature,  and  changes  its  composition.  The  gastric  juice  acts,  in 
a  manner  peculiar  to  itself,  on  the  food  exposed  to  its  action,  and  far  from 
inducing  a  beginning  of  putrefaction,  suspends  on  the  contrary,  and  cor- 
rects putrescency.  This  antiseptic  quality  of  the  gastric  juice,  suggest- 
ed the  practice  of  moistening  ulcers  with  it  to  accelerate  their  cure,  and 
the  experiments  made  at  Geneva  and  in  Italy,  have,  it  is  said,  been  fully 
successful.  I  have  made  similar  experiments  with  saliva,  which,  there 
is  every  reason  to  consider,  is  very  similar  to  the  gastric  juice,  and  I  have 
seen  old  and  foul  ulcers  assume  a  better  appearance,  the  granulations  be- 
come healthy,  and  the  affection  rapidly  advance  towards  a  cure,  from  the 
use  of  that  irritating  fluid.  I  had  under  my  care  an  obstinate  sore  on  the 
inner  ankle  of  the  left  leg  of  an  adult;  notwithstanding  the  external  ap- 
plication of  powdered  bark,  and  of  compresses  soaked  in  the  most  deter- 
gent fluids,  this  sore  was  improving  very  slowly,  when  I  bethought  my- 
self of  moistening  it  every  morning  with  my  saliva,  the  secretion  of  which 
was  increased  by  the  hideous  aspect  of  the  sore.  From  that  time,  the 
patient  evidently  mended,  and  his  wound  contracting  daily,  at  last  became 
completely  cicatrized. 

However  powerful  the  efficacy  of  the  gastric  juice,  to  dissolve  the  ali- 
mentary substances,  it  does  not  direct  against  the  coats  of  the  stomach 
its  active  solvent  faculty.  These  parietes  endowed  with  life,  powerfully 
resist  solution.  The  lumbrici  so  tender  and  delicate,  for  the  same  rea- 
son, can  exist  within  it,  without  being  in  the  least  affected  by  it,  and  such 
is  this  power  of  vital  resistance,  that  the  polypus  rejects  unhurt  its  arms, 
when  it  happens  to  swallow  them  among  its  foodf.  But  when  the  stomach 
and  the  other  organs  have  lost  their  vitality,  its  parietes  yield  to  the  sol- 
vent power  of  the  juices  which  it  may  contain,  they  become  softened,  and 


*  The  whole  of  this  sentence,  and  the  subsequent  one,  is  inapplicable.  When  we 
swallow  raw  oysters,  we  do  not  wait  for  them  to  soften  tlie  tongue  ,•  and  in  this  country, 
at  least,  daily  experience  teaches  that  they  are  extremely  nutritious. — Godman. 

•j-  It  had  been  thought,  that  no  animal  could  live  on  the  flesh  of  his  own  kind,  and 
this  circumstance  was  explained  on  the  same  principle  ;  but  to  refute  it,  we  need  only 
quote  the  instance  of  cannibals,  and  of  several  tribes  of  carniverous  animals,  who,  in  the 
absence  of  other  prey,  devour  one  another. — Author's  Note. 


95 

even  in  part  destroyed,  if  we  may  believe  Hunter,  who  found  its  inner 
membrane  destroyed  in  several  points  in  the  body  of  a  criminal,  \vhofor 
some  time  before  his  execution,  had  been  prevailed  upon,  in  considera- 
tion of  a  sum  of  money,  to  abstain  from  food*. 

The  gastric  juice  is  capable,  even  after  death,  of  dissolving  food  intro- 
duced into  the  stomach,  by  a  wound  made  into  it,  provided  the  animal 
still  preserves  some  degree  of  animal  heat.  It  acts  on  vegetable  and  ani- 
mal substances  triturated  and  put  into  a  small  vessel,  such  as  those  under 
which  Spallanzani,  in  his  experiments  on  artificial  digestion,  kept  up  a 
moderate  heat.  Let  us  not,  however,  consider  as  the  same,  this  solution 


.at  The  following  case  of  solution  of  the  stomach  after  death  came  under  the  observa- 
tion of  Professor  Haviland.  The  subject  was  a  young- man  whose  body  was  opened 
twelve  hours  after  death,  and  the  stomach,  on  being  examined  after  its  removal  from 
the  body,  presented  the  following  appearances: — The  mucous  membrane  seemed  more 
red  and  vascular  than  usual  throughout  its  whole  extent,  and  here  and 'there  were 
small  spots  of  what  seemed  to  be  extravasated  blood,  lying  beneath  the  mucous  coat, 
as  they  could  not  be  washed  oft,  nor  removed  by  the  edge  of  the  scalpel.  There  were 
two  holes  in  the  stomach  ;  the  larger  very  near  to  the  cardiac  end  of  the  small  curva- 
ture, and  on  the  posterior  surface ;  this  was  more  than  an  inch  in  length,  and  about 
half  an  inch  in  breadth  The  other,  not  far  from  the  former,  and  likewise  upon  the 
posterior  surface,  was  about  the  size  of  a  sixpence.  The  edges  of  these  holes  were 
smooth,  well  defined,  and  slightly  elevated.  The  coats  of  the  stomach  were  thin  in 
many  other  spots,  and  in  one  part  nothing  was  left  but  the  peritoneum,  the  mucous 
and  muscular  coats  being  entirely  destroyed  There  was  a  hole  in  the  diaphragm 
through  the  muscular  portion,  where  it  is  of  considerable  thickness,  large  enough  to 
admit  the  end  of  the  finger.  There  was  no  appearance  of  ulceration  or  of  pus  adher- 
ing to  the  edges  of  this  perforation  of  the  diaphragm.  Dr.  Haviland  concludes,  that, 
owing  to  the  activity  of  the  solvent  power  of  the  gastric  juice,  it  sometimes  not  only 
corrodes  the  parietesof  the  stomach,  but  even  the  thick  muscle  of  the  diaphragm,  and 

that  within  the  space  of  twelve  hours  after  death,  as  was  exemplified  in  this  case. 

Transactions  of  the  Cambridge  Philosophical  Society ,  Vol.  I.  Pan  II.  1S22. 

Hunter's  view  of  this  subject  has  been  disputed,  to  the  present  day,  by  several  emi- 
nent pathologists ;  but  Dr.  Philip's  observations  are  qualified  to  prove  it  in  a  very  satis- 
factory manner  to  those  who  yet  required  uriore  convincing  arguments.  On  opening 
the  abdomen  of  rabbits  which  had  been  killed  immediately  after  having  eaten,  and 
which  were  allowed  to  lie  undisturbed  for  some  time  before  the  examination,  he  has 
found  "the  great  end  of  the  stomach  soft,  eaten  through,  sometimes  altogether  con- 
sumed, the  food  being  only  covered  by  the  peritoneum,  or  lying  quite  bare  for  the 
space  of  an  inch  and  a  half  in  diameter;  and  part  of  the  contiguous  intestines,  In  the 
last  case,  also  consumed,  while  the  cabbage,  \\  hich  the  animal  had  just  taken,  lay  in 
the  centre  of  the  stomach  unchanged,  if  we  except  the  alteration  which  had  taken 
place  in  the  external  parts  of  the  muss  it  had  formed,  in  consequence  of  imbibing  gas- 
tric fluid  from  the  half-digested  food  in  contact  with  it." 

The  following  are  Dr.  Philip's  observations :— «  We  sometimes  found  the  great  end 
of  the  stomach  dissolved  within  an  hour  and  a  half  after  death.  It  was  more  frequently 
found  so  when  the  animal  bad  lam  dead  .for  many  hours.  This  effect  does  not  always 
ensue,  however  long  it  has  kin  dead.  It  seems  only  to  take  place  when  there  happens 
to  be  a  greater  than  usual  supply  of  gastric  fluid  ;  for  we  always  observed  it  most  apt 
to  happen  when  the  animal  had  eaten  voraciously. 

«  Why  it  should  take  place  without  the  food  being  digested,  is  evident  from  what 
has  been  said.    Soon  after  death,  the  motions  of  the  stomach,  which  are  constantly 
carrying  on  towards  the  pylorus  the  most  digested  food,  cease.     Thus,  the  food  which 
lies  next  to  the  surface  of  the  stomach,  becoming  fullv  saturated  with  gastric  fluic 
neutralizes  no  more,  and  no  new  food  being  presented  to  it,  it  necessarilf  acts  on  the 
tomach  itself,  now  deprived  of  life,  and,  on  this  account,  as  Mr.  Hunter  justly  observes 
equally  subject  to  its  action  with  other  dead  an-mal  matter.    It  is  remarkable  that  ti'e 
gastric  fluid  of  the  rabbit,  which  in  its  natural  state  refuses  animal  food,  should  so  com 
pletely  digest  its  own  stomach  as  not  to  leave  a  trace  of  the  parts  acted  on     T  never 

endi  in  ou'erparts> "*  intemal 


96 

of  the  food  in  the  gastric  juice,  out  of  the  stomach,  and  that  which  oc- 
curs in  digestion  within  the  organ.  Every  thing  tends  to  show,  that  the 
stomach  ought  not  to  be  considered  as  a  chemical  vessel,  in  which  there 
takes  place  a  mixture  giving  rise  to  new  combinations.  The  tying  the 
nerves  of  the  eighth  pair,  the  use  of  narcotic  and  of  opium,  intense 
thought,  every  powerful  affection  of  the  mind,  trouble  or  even  gaiety, 
entirely  suspend  digestion  in  the  stomach,  which  cannot  take  place  inde- 
pendently of  nervous  influence.  Yet  this  nervous  influence  may  possi- 
bly not  concur  directly,  and  of  itself,  to  stomachic  digestion;  it  is  perhaps 
merely  relative  to  the  secretion  of  the  gastric  juice,  which  the  ligature  of 
the  nerves,  the  action  of  narcotics  or  of  other  substances  may  impede, 
alter,  or  even  completely  suspend. 

It  is  now  very  generally  admitted,  that  digestion  in  the  stomach  c£n- 
sists  in  the  solution  of  the  Ibod  in  the  gastric  juice.  This  powerful  sol- 
vent penetrates,  in  every  direction,  the  alimentary  mass,  removes  from 
one  another,  or  divides  its  molecules,  combines  with  it,  alters  its  inward 
composition,  and  imparts  to  it  qualities  very  different  from  those  which 
it  possessed  before  the  mixture.  If,  in  fact  a  mouthful  of  wine  or  of 
food  is.  rejected,  a  few  minutes  after  being  swallowed,  the  smell,  the  fla- 
vour, all  the  sensible  and  chemical  qualities  of  such  substances,  are  so 
completely  altered,  that  they  can  scarcely  be  recognized;  the  vinous 
substances  turned,  to  a  certain  degree,  sour,  are  no  longer  capable  of  the 
acetous  fermentation.  The  energy  of  the  solvent  power  of  the  gastric 
juice,  perhaps  over-rated  by  some  physiologists,  is  sufficient  to  dissolve 
and  reduce  into  a  pulp,  the  hardest  bones  on  which  some  animals  feed. 
It  is  highly  probable,  that  its  chemical  composition  varies  at  different 
times;  that  it  is  acid,  alkaline  or  saponaceous,  according  to  the  nature  of 
the  food.  Although  the  gastric  juice  be  the  most  powerful  agent  of  di- 
gestion, its  solvent  power  requires  to  be  aided  by  several  secondary 
causes,  as  warmth,  which  seems  to  increase,  and,  in  a  manner,  to  concen- 
trate itself  in  the  epigastric  region  as  long  as  the  stoti'.ach  is  engaged 
in  digestion  ;  a  sort  of  inward  fermentation  which  cannot  be,  strictly 
speaking,  compared  to  the  decomposition  which  substances,  subject  to- 
putrefaction  and  acescency  undergo.  The  gentle  and  peristaltic  action 
of  the  muscular  fibres  of  the  stomach,  which  press  in  every  direction,  on 
the  alimentary  substance,  performs  on  it  a  slight  trituration,  while  the 
moisture  of  the  stomach  softens  and  macerates  the  food,  before  it  is  dis- 
solved ;  one  might  therefore  say,  that  the  process  of  digestion  is  at  once 
chemical,  mechanical,  and  vital ;  in  that  case,  the  authors  of  the  theories 
that  have  been  broached,  have  been  wrong,  only  in  ascribing  to  one  cause, 
such  as  heat,  fermentation,  putrefaction,  trituration,  maceration,  and  the 
action  of  the  gastric  juice,  a  process  which  is  the  result  of  a  concurrence 
of  these  causes  united*. 

The  food  remains  in  the  stomach,  during  a  longer  or  shorter  space  of 


*  Dr.  A.  Wilson  Philip  has  lately  made  some  experiments  to  prove,  that  when  the 
nerves  going-  to  the  stomach  are  divided,  the  digestion  of  the  food  may,  notwithstand- 
ing, be  produced,  by  passing*  a  current  of  the  galvanic  fluid,  so  as  to  form  a  communi- 
cation between  the  ends  of  the  cut  nerves.  We  are  not,  however,  so  willing  to  draw 
the  inference,  that  the  nervous  power,  or  influence,  is  identical  with  the  galvanic  agent. 
The  nerves,  in  his  experiments,  were  not  all  divided ;  and  we  can  readily  conceive  how 
so  powerful  a  stimulus  as  galvanism,  might  excite  the  remaining  nerves  sufficiently  to 
produce  the  effect  reported  by  Dr.  Wilson. —Godman. 


97 

time,  according  as  by  its  nature,  it  yields  more  or  less  readily  to  the 
changes  which  it  has  to  undergo.  Gosse  of  Geneva,  ascertained,  by  ex- 
periments performed  on  himself,  that  the  animal  and  vegetable  fibre,  con- 
crete albumen,  white  and  tendinous  parts,  paste  containing  fat  or  butter, 
substances  which  have  either  not  undergone  fermentation,  or  which  do 
not  readily  undergo  that  process,  remain  longer  in  the  stomach,  offer 
more  resistance  to  the  gastric  juice,  than  the  gelatinous  parts  of  animals 
or  vegetables,  fermented  bread,  Sec.;  that  the  latter  required  but  an  hour 
for  their  complete  solution,  while  the  former  were  scarcely  dissolved,  at 
the  end  of  several  hours. 

XXI.  The  following  case  throws,  I  think,  some  light  on  the  mechan- 
ism and  importance  of  the  action  of  the  stomach  in  digestion.  The  pa- 
tient was  a  woman  whom  I  had  frequent  opportunities  of  examining  at 
the  "  hopital  de  la  charite,"  at  Paris,  in  the  clinical  wards  of  Professor 
Corvisart,  in  which  she  died  on  the  9tn  Nov.  of  the  year  1807,  after  six 
months'  stay  in  the  hospital* 

A  fistulous  opening,  of  an  oval  form,  an  inch  and  a  half  in  length,  and 
upwards  of  an  inch  in  breadth,  situated  at  the  lower  part  of  the  chest,  at 
the  upper  and  left  side  of  the  epigastric  region,  afforded  an  opportunity 
of  viewing  the  inner  part  of  the  stomach,  which,  when  empty  of  food, 
appeared  of  a  vermilion  colour,  was  covered  with  mucus,  its  surface 
wrinkled  over  with  folds  about  half  an  inch  deep,  and  enabled  one  to  dis- 
tinguish the  vermicular  undulations  of  these  folds,  and  of  all  the  parts 
which  were  in  sight.  The  patient,  who  was  then  forty-seven  years  of 
age,  had  this  fistula  since  she  was  in  her  thirty-eighth  year.  Eigh- 
teen years  before,  she  had  fallen  on  the  threshold  of  a  door,  the  blow 
had  struck  against  her  epigastric  region.  The  place  remained  affected 
with  pain,  and  she  became  incapable  of  walking  or  of  sitting,  otherwise 
than  bent  forward  and  to  the  left  side.  At  the  end  of  this  long  interval 
a  phlegmonous  and  oblong  tumour  appeared  on  the  injured  spot :  during 
the  nausea  and  vomiting  which  came  afterwards,  the  tumour  broke,  and 
there  escaped  at  the  wound,  which  was  left  by  this  rupture,  two  pints  of 
a  fluid  which  the  patient  had  just  swallowed  to  obtain  relief.  From  that 
time,  the  fistula,  which  at  first,  would  scarcely  have  admitted  the  tip  of 
the  little  finger,  increased  daily  j  at  first  it  allowed  only  the  fluids  to  pass, 
but,  on  the  eighth  day,  the  solid  food  came  away  freely,  and  continued  to 
do  so  till  she  died.  When  admitted  into  the  hospital,  she  ate  as  much  as 
three  women  of  her  age,  she  voided  about  a  pint  of  urine,  and  went  to 
stool  only  once  in  three  days.  Her  faeces  were  yellowish,  dry,  rounded, 
and  weighed  more  than  a  pound.  Her  pulse  was  very  feeble  and  ex- 
tremely slow,  its  pulsation  scarcely  exceeding  forty-five  or  forty-six  beats 
in  a  minute.  Three  or  four  hours  after  a  meal,  an  irresistible  desire 
obliged  her  to  take  off  the  lint  and  compresses  with  which  she  covered 
the  fistulous  opening,  and  to  give  vent  to  the  food  which  her  stomach 
might  happen  to  contain;  it  came  out  rapidly,  and  there  escaped  at  the 
same  time,  and  with  a  noise,  a  certain  quantity  of  gases.  The  food  thus 
evacuated,  exhaled  an  insipid  smell,  was  neither  acid  nor  alkaline,  for,  the 
chymous  and  greyish  coloured  pulp  into  which  they  were  reduced,  when 
suspended  in  a  certain  quantity  of  distilled  water,  did  not  affect  vegetable 
blues.  The  digestion  of  the  food  was  far  from  being  always  complete  ; 
sometimes,  however,  the  smell  of  wine  could  not  be  recognized,  and 
the  bread  formed  a  viscid,  thick,  and  soft  substance,  similar  to  fibrine 

N 


98 


newly  precipitated  by  the  acetous  acid,  and  it  floated  in  a  tenacious  liquid 
of  the  colour  of  common  broth*. 

It  follows,  from  the  experiments  performed  at  the  Ecole  de  Medicine, 
on  these  half  digested  substances,  and  on  the  same  before  their  admission 
into  the  stomach,  that  the  changes  which  they  undergo,  consist  in  the  in- 
crease of  gelatine,  in  the  formation  of  a  substance  which  has  the  appear- 
ance of  fibrine,  without  having  all  its  qualities,  in  a  greater  proportion  of 
muriate  and  phosphate  of  soda,  as  well  as  of  phosphate  of  lime. 

This  patient  was  unable  to  sleep,  till  she  had  emptied  her  stomach, 
which  she  cleared  by  swallowing  a  pint  of  infusion  of  chamomile.  In  the 
morning,  there  was  seen  in  the  empty  stomach  a  small  quantity  of  a  ropy- 
frothy  fluid,  like  saliva.  It  did  not  turn  vegetable  blues  to  a  green  or 
red  colour,  was  not  homogeneous,  but  exhibited  particles,  of  some  de- 
gree of  consistence,  among  the  more  fluid  parts,  and  even  albuminous 
flakes  completely  opaque.  The  experiments  performed  on  this  fluid, 
showed  that  it  bore  a  considerable  analogy*4o  saliva,  which,  however,  is 
rather  more  liable  to  putrefaction. 

The  vermicular  motion  by  which  the  stomach  cleared  itself  of  its  con- 
tents, took  place  in  two  different,  but  not  in  opposite  directions,  the  one 
pressing  the  food  towards  the  fistulous  opening,  the  other  towards  the 
pylorus,  through  which  the  smaller  quantity  was  allowed  to  pass. 

On  opening  the  body,  it  was  found,  that  the  fistula  extended  from  the 
cartilage  of  the  seventh  left  rib,  as  high  as  the  osseous  termination  of  the 
sixth ;  its  edges  were  rounded,  and  from  three  to  four  lines  in  thickness; 
they  were  covered  with  a  thin  moist  skin,  of  a  red  colour,  and  similar  to 
that  of  the  lips.  The  peritoneal  coat  of  the  stomach  adhered  so  firmly 
to  the  peritoneum  lining  the  fore  part  of  the  abdomen,  around  the  open- 
ing, that  the  line  of  adhesion  would  notbe  observed.  The  opening  was 


*  Dr.  Prout  has  made  several  experiments  in  order  to  ascertain  the  chemical  com- 
position of  the  chyme,  from  which  he  obtained  the  following  results  : — • 

No.  1.  Chyme  of  a  dog  fed  on  vegetable  food.  Composed  of  a  semi-fluid,  opake,  yel- 
lowish white  part,  containing  another  portion  of  similar  colour,  but  of  firmer  consist- 
ence mixed  with  it.  Spec.  grav.  1.056.  It  showed  no  traces  of  a  free  acid,  or  alkali, 
but  coagulated  milk  completely,  when  assisted  by  a  gentle  heat. 

No.  3.  Chyme  of  a  dog1  fed  on  animal  food.  This  was  more  thick  and  viscid  than 
No.  1.  and  its  colour  was  more  inclining;  to  red.  Spec.  Grav.  1.022.  It  showed  no 
traces  of  a  free  acid,  or  alkali,  nor  did  it  coagulate  milk,  even  when  assisted  by  the 
most  favourable  circumstances. 

On  being  subjected  to  analysis,  these  two  specimen's  of  chyme  were  found  to  con- 
sist of — 


A.  Water,  ..... 

1.  Chyme  from 
vegetable  food. 
86-5 

2.  Chyme  from 
animal  food. 
80« 

B.  Gastric  principle,  or  mucus  united  with  aiimen- 
tary  matters,  and  apparently  constituting  the 
chyme,  properly  so  called,  mixed  with  excre- 
mentitious  matter,  ......  .  .'  

I 

6     • 

15-8 

C.  Albuminous  matter,  chiefly  fibrine,  

1-3 

1-6 

1*7 

E.  Vegetable  gluten,  

5- 

.7 

.7 

G.  Insoluble  residuum,  , 

.2 

•5 

100- 

100- 

F.  The  saline  matters  were  obtained  by  incineration,  and  consisted  chiefly  of  the  mu- 
riates, sulphates,  and  phosphates.— Copland. 


99 

in  the  anterior  part  of  the  stomach,  at  the  unienoi'  the  two-thirds  on  the 
left  side,  with  the  third  on  the  right  of  that  viscus  ;  that  is,  about  eight 
fingers'  breadth  from  its  greater  extremity,  and  only  four  from  the  py- 
lorus. It  extended  from  the  greater  to  the  lesser  curvature,  In  other 
respects,  it  was  the  only  organic  affection  of  that  vkcus. 

It  should  be  stated,  that  for  several  years,  the  patient  had  been  thin 
and  emaciated,  and  had  led  a  languid  life,  which  was  terminated  by  a  col- 
liquative  diarrhoea.  She  seemed  to  be  supported  only  by  the  small  quan- 
tity of  food  which  passed  through  the  pylorus,  into  the  duodenum,  where 
it  received  the  influence  of  the  bile,  whose  action  on  the  chyme,  is,  as 
we  shall  presently  state,  absolutely  essential  to  the  separation  of  the  nu- 
tritious parts*.  Not  that  there  was  any  thing  to  prevent  the  absorbents  of 
the  stomach  from  taking  up  a  certain  quantity  of  nutritious  particles,  but 
that  small  quantity  of  food  in  an  imperfect  condition,  was  of  very  little 
service  in  imparting  nourishment,  and,  in  that  respect,  she  was  in  similar 
circumstances  to  patients  who  are  affected  with  obstruction  of  the  pylo- 
rus, and  reject  the  greater  part  of  their  food,  when,  digestion  being  over, 
this  contracted  opening  can  no  longer  allow  any  food  to  passf. 

XXII.  While  the  alimentary  solution  is  going  on,  the  two  openings  of 
the  stomach  remain  perfectly  closed ;  no  gas  disengaged  from  the  food, 
escapes  along  the  oesophagus,  except  when  digestion  is  imperfect.  A 
slight  shivering  is  felt,  the  pulse  becomes  quicker,  and  more  contracted, 
the  vital  power  seems  to  forsake  the  other  organs,  to  concentrate  itself 
on  that  which  is  the  seat  of  the  digestive  process.  The  parietes  of  the 
stomach  are  soon  called  into  action ;  its  circular  fibres  contract  in  differ- 
ent points ;  these  peristaltic  oscillations,  at  first  irregular  and  uncertain, 
acquire  more  regularity,  and  act  from  above  downwards,  and  from  the 
left  to  the  right,  that  is  to  say,  from  the  cardiac  to  the  pyloric  orifice.  Be- 
sides, its  longitudinal  fibres  shorten  it,  in  the  fcv***imr6f  its  greatest  dia- 
meter, and  bring  nearer  to  each  other  it3  two  orifices.  In  these  different 
motions,  the  stomach  rises  over  che  pylorus,  so  that  the  angle  which  it 
forms  with  the  duoden«ru>  almost  entirely  ceases,  and  this  facilitates  the 
escape  of  the  food.  It  has  been  observed,  that  during  sleep,  digestion 
takes  place  much  more  readily,  when  we  lie  on  the  right,  than  on  the 
left  side,  and  this  circumstance  has  been  ascribed  to  the  compression  of 
the  liver  on  the  stomach.  It  is  much  more  likely  to  depend  on  the  cir- 
cumstance, that  when  we  He  on  the  right  side,  the  passage  of  the  food  is 
facilitated  by  its  own  weight,  the  natural  obliquity  of  the  stomach,  from 


*  This  is  very  satisfactorily  demonstrated  by  the  experiments  of  B.  C.  Brodie,  F.  R. 
S.  He  applied  ligature's  on  the  common  gall  duct  (choledochus  communis)  and  found 
that  the  change  of  the  materials  taken  into  the  stomach  was  affected  as  usual.  Chyme 
was  formed.  But  when  the  chyme  passed  into  the  intestines,  there  was  no  chyle  pro- 
duced, nor  could  any  trace  of  it  be  found  in  the  intestines  or  lacteal*.  As  the  mass  ap- 
proached the  larger  intestines,  is  became  thicker,  by  the  absorption  of  the  watery  parts, 
but  without  any  other  change. 

As  the  results  obtained  in  Mr.  Brodie's  experiments  were  uniformly  the  same,  we  be- 
lieve him  justified  in  concluding,  "  that  the  office  of  the  bile  is  to  change  the  nutritious 
part  of  the  chyme  into  chyle  ;  and  to  separate  from  it  the  excrementitious  matter."  See 
Phil,  and  Med.  Jour.  No.  12,  p.  400.— Godman. 

f  Cases,  in  many  respects  similar  to  the  above,  are  recorded  by  different  writers. — 
Haller,  in  his"  Chirurgical  Dissertations,"  has  the  history  of  a  woman  with  an  aperture 
in  her  stomach,  through  which  she  was  nourished  for  twenty-seven  years.  For  other  in- 
stances of  tistulous  openings  in  this  viscus,  consult  the  "  Irish  Transactions,"  and  "Me- 
dical Facts  and  Observations. " —  Chapman. 


100 

left  to  right,  being  increased  by  the  changes  attending  the  prts§Hce  of  the 
food. 

XXIII.  On  the  Uses  of  the  Pylorus.  The  pyloric  orifice  is  furnished 
with  a  muscular  ring,  covered  over  by  a  fold  of  the  mucous  membrane 
of  the  stomach.  This  kind  of  sphincter  keeps  it  perfectly  closed,  while 
digestion  is  going  on  in  the  stomach,  and  will  not  allow  a  free  passage  to 
the  food  which  has  not  yet  undergone  a  sufficient  change.  The  pylorus, 
which  is  endowed  with  a  peculiar  and  delicate  sensibility,  may  be  con- 
sidered as  a  vigilant  guard,  which  prevents  any  thing  from  passing  into 
the  intestinal  canal,  till  it  has  undergone  the  necessary  changes.  Seve- 
ral authors  quoted  by  Haller,  have,  very  justly,  observed,  that  the  ali- 
mentary substances  do  not  leave  the  stomach  in  the  same  order  that  they 
were  received  into  it,  but  that  they  are  evacuated  according  to  their  de- 
grees of  digestibility. 

One  may  say,  that  there  really  takes  place  in  the  stomach,  a  sorting  of 
the  different  substances  which  it  contains.  Those  that  are  most  readily 
dissolved,  get  near  to  the  pylorus,  which  admits  them,  rejecting  those 
which,  not  yet  sufficiently  digested,  cannot  produce  on  it  the  necessary 
affection.  To  this  delicacy  of  tact,  which  I  ascribe  to  the  pylorus,  will 
be  objected,  perhaps,  the  passage  it  allows  to  pieces  of  money  and  other 
foreign  indigestible  substances.  But  these  bodies,  which  have  always 
lain  some  time  in  the  stomach,  before  they  make  their  way  into  the  in- 
testines, repeatedly  attempt  the  orifice  of  the  pylorus,  and  pass  through, 
only  when  they  have  at  last  accustomed  it  to  their  contact.  The  gastric 
system  is  under  the  laws  of  a  secretory  gland;  and  as  the  roots  of  the 
excretory  ducts,  being  endued  with  a  sort  of  elective  sensibility,  will  not 
receive  the  secreted  fluid,  until  it  has  undergone  the  necessary  prepara- 
tion in  the  glandular  parenchyma,  in  the  same  manner,  the  pylorus  ad- 
mits aliments,  and  givc»  them  passage  into  the  intestines,  which  may  be 
regarded  as  the  excretory  ducia  of  the  stomach,  only  when  they  have 
been  sufficiently  elaborated  by  the  action  uf  this  organ. 

XXIV.  As  the  stomach  empties  itself,  the  spaatn  of  the  skin  goes  off; 
the  shivering  is  followed  by  a  gentle  warmth;  the  pulse  increases  in  ful- 
ness and  frequency;  the  insensible  perspiration  is  augmented.  Diges- 
tion brings  on,  therefore,  a  general  action  analogous  to  a  febrile  paroxysm; 
and  this  fever  of  digestion,  noticed  already  by  the  ancients,  is  particu- 
larly observable  in  women  of  great  sensibility.  Nothing  positive  can 
be  said  on  the  duration  of  stomachic  digestion;  food  passes  sooner  or 
slower  from  the  stomach,  according  as  its  nature  is  such  as  to  resist,  more 
or  less,  the  actions  which  tend  to  dissolve  it ;  according  too  to  the 
strength  and  vigour  of  the  stomach  at  the  time,  and  to  the  activity  of  the 
gastric  juices.  Yet  we  may  state  from  three  to  four  hours  as  the  mean 
time  of  their  remaining  there.  It  is  of  consequence  to  know  the  time  re- 
quired for  digestion  in  the  stomach,  that  we  may  not  disturb  it  by  baths, 
bleedings,  &c.  which  would  call  off  towards  other  organs,  those  powers 
which  ought,  at  that  time,  to  be  concentrated  upon  the  stomach. 

If,  as  is  indisputable,  the  stomach  carries  with  it,  into  its  action,  all  the 
other  organs  of  the  economy;  if  it  summons  to  its  aid,  so  to  say,  the 
whole  system  of  the  vital  powers;  if  this  sort  of  derivation  is  the  more 
conspicuous,  as  the  organization  is  more  delicate,  the  sensibility  more 
lively,  the  susceptibility  greater,  the  importance  is  apparent  of  enforcing 
a  strict  diet  in  acute  diseases,  and  in  all  cases  where  Nature  is  engaged 
in  an  organic  operation,  which  a  little  increase  of  irritation  could  not  fail 


101 

to  disorder,  or  to  break  oft'.  Those  who  have  practised  in  great  hospi- 
tals, know  to  how  many  patients  indigestions  are  fatal.  I  have  seen  some 
•with  large  ulcers;  suppuration  was  copious  and  healthy;  the  granula- 
tions florid,  and  all  promising  a  happy  issue,  when  ignorant  friends  bring 
them  by  stealth  indigestible  food,  with  which  they  cram  themselves,  in 
spite  of  the  utmost  watchfulness.  The  stomach,  used  to  mild  and  mode- 
rate regimen,  at  once  overloaded  with  food,  is  changed  into  a  centre  of 
fluxion,  towards  which  the  blood  all  tends.  An  irritation  is  produced 
beyond  that  on  the  ulcerated  surface ;  which,  in  a  little  time,  ceases 
to  secrete  pus,  the  fleshy  granulation  become  flabby,  extreme  op- 
pression is  felt ;  with  a  difficulty  of  breathing  comeson  a  pungent  pain  in 
the  side,  the  pain  sympathetically  felt  in  the  lungs,  makes  this  organ  the 
seat  of  an  inflammatory  and  purulent  congestion,  a  rattle  ensues,  and  the 
patients  die  of  suffocation,  at  the  end  of  two  or  three  days,  sometimes 
in  twenty-four  hours;  and  this  fatal  termination  is  especially  accelerated, 
when,  as  I  have  often  witnessed,  a  blister  is  applied  to  the  seat  of  the 
pain,  instead  of  the  ulcerated  surface. 

It  will  seem  surprising,  perhaps,  that  in  the  case  of  which  I  have  just 
been  speaking,  it  should  be  in  the  lungs,  and  not  the  stomach  itself,  that 
the  congestion  and  the  pain  take  place;  but  besides  that  the  most  per- 
meable organ  of  the  body,  is  the  lungs,  as  well  as  the  weakest,  and  the 
most  easily  yielding  to  fluctionary  motion* ',  a  host  of  instances  prove,  what 
a  close  sympathy  unites  it  to  the  stomach.  Let  us  but  call  to  mind  pleuri- 
sies and  bilious  peripneumonies,  those  acute  pains  of  the  side,  which, 
since  Stahl,  physicians  have  so  successfully  treated  with  vomits.  The 
rapidity  with  which  their  symptoms  go  off,  on  the  evacuation  of  the 
sordes  which  oppress  the  stomach,  shows  clearly  that  the  sympathetic 
diseases  are  not  owing  to  the  metastasis  of  bile  upon  the  lungs,  and  that 
they  do  not  consist  in  the  simultaneous  existence  of  a  gastric  affection, 
and  of  an  inflammatory  state  of  the  pleura  or  of  the  lungs,  but  that  they 
are  simple  gastric  affections,  in  which  the  lungs  are,  at  the  same  time, 
the  seat  of  a  sympathetic  pain. 

The  action  of  the  parietes  of  the  stomach  ceases,  only  when  this  viscus 
is  completely  cleared  of  the  food  it  contained.  The  gastric  juice,  no 
longer  secreted,  ceases  to  be  poured  so  freely  by  its  arteries,  and  the 
parietes,  which  close  upon  each  other,  are  chiefly  lubricated  by  the 
mucus  so  plentifully  secreted  by  the  inner  coat. 

At  times,  the  action  of  the  muscuiarfibresof  the  stomach  is  altogether 
inverted,  they  contract  from  the  pyloris,  towards  the  cardia,  and  this 
anti-peristaltic  motion,  in  which  the  contractions  are  effected  with  more 
force,  more  rapidly,  and  in  a  manner  really  convulsive,  produces  vomit- 
ing. Then,  the  action  of  the  abdominal  muscles  is  added  to  that  of  the 
stomach  ;  the  viscera  are  driven  upwards  and  backwards,  by  the  contrac- 
tion of  the  larger  muscles  of  the  abdomen ;  the  diaphragm  rises  up  to- 
wards the  chest.  If  it  sunk  as  it  contracted,  the  oesophagus,  which 
passes  in  the  interval  of  its  two  crura,  would  be  compressed,  and  the  pas- 
sage of  the  alimentary  substances  by  the  cardiac  orifice,  could  not  take 
place.  Accordingly  it  is  observecJ,  that  it  is  only  during  expiration,  that 
any  thing  passes  from  the  stomach  into  the  oesophagus.  Vomiting  may 

*  Of  all  the  erg-ads  it  is  that  in  which  we  most  meet  with  organic  injury;  and  those 
who  have  opened  many  bodies,  may  have  observed,  how  rare  it  is  to  find  the  lungs 
completely  sound  in  adults  and  in  old  men. — Author's  J\ *ote. 


102  .    ||| 

depend  upon  the  obstruction  of  the  pylorus*, on  the  too  irritating  impres- 
sion of  any  substance  on  the  coats  of  the  stomach ;  it  may  be  produced 
by  the  irritation  of  some  other  organ  with  which  the  stomach  is  in  sym- 
pathy, &c. 

Digestion  in  the  stomach  is  essentially  assistefl  by  nervous  influence. 
Many  physiologists,  since  Brunner,  have  found  that  the  tying  of  the  eighth 
pair  of  nerves  (the  pneumo-gastric)  provoked  vomiting  and  retarded 
the  work  of  digestionf.  As  it  is  impossible  to  make  this  experiment 
without  effecting  respiration,  a  function  of  very  different  importance,  it 
becomes  difficult  to  know,  whether  the  derangement  of  digestion  did  not 
proceed  from  the  general  disturbance  brought  upon  all  the  functions: 
however,  the  brain  does  appear  to  be  in  more  immediate  sympathy  with 
the  stomach,  than  with  any  other  part  of  the  digestive  tube.  Disgust 
from  the  recollection  of  loathed  food  excites  vomiting.  A  more  than 
ordinary  exertion  of  the  brain  relaxes,  disorders,  and  will  even  suspend, 
altogether,  the  functions  of  the  stomach:  an  unexpected  piece  of  news, 
a  violent  emotion,  are  attended  with  a  cessation  of  the  strongest  sensation 
of  hunger.  It  would  be  useless  to  bring  together,  in  this  place,  proofs  of 
the  intimate  connexion  subsisting  between  the  brain  and  the  stomach, 
through  the  intervention  of  the  pneumogastric  nerves,  for  the  connexion 
is  questioned  by  no  onej. 

XXV.  Of  Digestion  in  the  Duodenum.  The  food,  on  quitting  the  sto- 
mach, enters  the  duodenum,  and  there  experiences  new  changes,  as  es- 
sential as  those  which  were  produced  upon  it,  by  digestion  in  the  sto- 
mach. It  might  even  be  said,  that  as  the  essence  of  digestion  and  its 
principal  object  is  the  separation  of  the  food  into  two  parts,  the  one  re- 
crementitious  and  the  other  chylous  or  nutritious,  the  duodenum,  in 
which  that  separation  is  performed,  is  its  principal  organ.  In  fact,  how- 
ever carefully  one  may  examine  the  greyish  chyme  which  is  sent  out  of 
the  stomach,  it  will  be  discovered  to  be  a  mere  slimy  homogeneous  pulp ; 
and  in  more  than  a  hundred  animals  which  I  have  opened  during  the  pro- 
cess of  digestion,  I  never  observed  the  absorbents  of  the  stomach  filled 
with  real  chyle,  like  those  of  the  intestines. 

The  duodenum  may  be  considered  as  a  second  stomach,  very  distinct 
from  the  other  small  intestines,  by  its  situation  exterior  to  the  perito- 
neum, by  its  size,  and  by  its  readiness  of  dictation,  the  size  and  regula- 
rity of  its  curvatures,  the  great  number  of  valvulse  conniventes  with 
which  its  inner  part  is  furnished,  the  prodigious  quantity  of  chylous  ves- 
sels which  arise  from  it,  and  especially  by  its  receiving,  within  its  cavity, 
the  biliary  and  pancreatic  fluids.  If  the  situation  of  the  duodenum  and 
the  peculiarities  of  its  structure  are  attended  to,  it  will  be  readily  observ- 
ed, that  every  thing  in  that  intestine,  tends  to  slacken  the  course  of  the 


*  The  best  description  of  the  pyloris  is  given  by  BLUMEJTBACH  from   LEVELLING, 
who  designates  in  an  annular  fold,  "  consisting1  not,  like  the  other  i-ugac  of  the  stomach, 
of  merely  the  mucous,  but  also  of  fibres  derived  from  the  nervous  and  musular  coats. 
All  these,  united,  form  a  conoidal  opening'  at  the  termination  of  the  stomach,  project- 
ing- into  the  duodenum,  as  the  uterus  docs  into  the  vaginia,  and,  in  a  manner,  embraced 
by  it."—  Copland. 

•\  Dr.  Haig-hton  lias  proved,  in  the  most  satisfactory  manner,  that  a  lig-ature  on  the 
eighth  pair  of  nerves,  far  from  inducing-  vomiting-,  renders  the  stomach  incapable  of 
rejecting  its  contents,  even  though  excited  by  the  most  powerful  emetics. — See  Me- 
znoirs  of  the  London  Medical  Societv  Trans.  Vol.  II.  P-  512. — DeLvs. 

*  See  APPENDIX,  Note  L. 


103 

alimentary  substance,  and  to  prolong  its  stay  within  it,  that  it  may  re- 
main the  longer  exposed  to  the  action  of  these  fluids. 

The  duodenum  is,  in  fact,  almost  entirely  uncovered  by  the  peritoneum, 
a  serous  membrane,  which  like  all  those  that  line  the  inside  of  the  great 
cavities,  and  reflect  themselves  over  the  viscera  which  they  contain,  by 
furnishing  them  external  coverings,  admits  but  of  little  extension,  and 
seems  to  stretch,  when  these  viscera  become  dilated,  only  by  the  unfold- 
ing of  its  numerous  duplicaiures.  Fixed  by  a  rather  loos*  cellular  tissue 
to  the  posterior  side  of  the  abdomen,  the  duodenum  is  susceptible  of  such 
dilatation,  as  to  equal  the  stomach  in  size,  as  is  sometimes  seen  in  open- 
ing dead  bodies.  Its  curvatures  depend  on  the  neighbouring  organs,  and 
seem  almost  invariably  fixed;  lastly,  numerous  valyulse  line  its  inner  sur- 
face, so  as  to  add  to  the  friction,  and  to  increase  the  extent  of  surface,  and 
thereby  the  number  of  absorbents  destined  to  take  up  the  chyle  separated 
in  the  duodenum,  from  the  excrementitious  part  of  the  food,  by  the  action 
of  the  fluids  poured  into  it,  from  the  united  ducts  of  the  liver 'and  pan- 
creas*. 

XXVI.  Of  the  Bile  and  of  the  Organs  which  serve  for  its  secretion.  The 
bile  is  a  viscous,  bitter,  and  yellowish  fluid,  containing  a  great  quantity 
of  water,  of  albumen  to  which  it  owes  its  viscid  condition,  and  oil  to 
which  the  colouring  and  bitter  principle  is  united.  Soda,  to  which  the 
bile  owes  the  property  of  turning  vegetable  blues  to  a  green  colour,  phos- 
phates, carbonates,  and  muriates  of  soda,  phosphates  of  lime,  and  of  am- 
monia j  and,  lastly,  as  some  say,  oxide  of  iron,  and  a  saccharine  substance 
resembling  the  sugar  of  milk.  This  fluid,  which  the  ancients  Looked  upon 
as  animal  soap,  fitted  for  effecting  a  more  intimate  mixture  of  the  alimen- 

*  The  muscular  coat  of  the  duodenum  is  thicker  than  that  of  the  small  intestines, 
the  base  of  the  villi  of  the  mucous  tunic  is  more  thickly  set  with  glandular  follicles, 
and  the  wjiole  duodenum  presents  a  more  vascular  appearance  than  any  other  portion 
of  the  intestines. 

The  experiments  of  Dr.  PROUT  on  chyme,  taken  from  the  duodenum,  exhibit  the 
following1  results : — 

1.  VEGETABLE  FOOD. 

Composed  of  a  semi-fluid,  opake,  yellowish  white  part,  having-  mixed  with  it  an- 
other portion  of  similar  colour,  but  of  firmer  consistence.  It  coagulated  milk  com- 
pletely. 

AVater, 86-5 

Chyme,  &c g. 

"Biliary  principle,     .         .         .        ,  1-5 

Vegetable  gluten,    ....  5. 

Saline  matter,          «...  .7 

Insoluble  residuum,          ...  -2 

100 
2.  ANIMAL  FOOD. 

More  thick  and  viscid  than  chyme  from  vegetable  food,  and  its  colour  more  inclining: 
to  red.  Did  not  coagulate  milk. 

Water, 80- 


Chyme,  &c.     . 
Albuminous  matter 
Biliary  principle, 
Saline  matters, 
Isoluble  residuum, 


15-8 

1-3 

1-7 

•7 

•5 

100 


104 

tary  matter,  by  combining  its  watery  with  its  fat  and  oily,  parts,  is  there- 
fore, extremely  compound  :  it  is  at  once  watery,  albuminous,  oily,  alka- 
line, and  saline*.  The  liver  which  secretes  it,  is  a  very  bulky  vis- 
cus,  situated  in  the  upper  part  of  the  abdomen,  and  kept  in  its  place, 
chiefly  by  its  attachment  to  the  diaphragm,  of  which  it  follows  all  the 
motion. 

The  hepatic  artery,  which  the  creliac  sends  off  to  the  liver,  supplies  it 
only  with  the  blood  requisite  for  its  nutrition  :  the  materials  of  its  secre- 
tion are  brought  by  the  blood  of  the  vena  portse. 

This  opinion  on  the  uses  of  the  hepatic  artery,  which  I  take  up  with 
Haller,  cannot  rest  upon  the  experiments  of  those  who  pretend  to  have 
seen  the  secretion  of  the  bile  going  on,  after  it  was  tied.  Besides  that 
the  position  of  this  vessel  makes  the  operation  almost  impossible,  which 
gives  me  reason  to  doubt  if  ever  it  was  practised  ;  and  if  it  were,  by  in- 
tercepting the  course  of  the  arterial  blood  carried  to  the  liver,  this  viscus, 
even  under  the  received  hypothesis,  would  remain  deprived  of  nourish- 
ment and  of  action  :  and  the  vena  portse  would  supply  it,  in  vain,  with  a 
blood  on  which  it  could  exert  no  influence*  When  this  vein  is  tied,  which 
it  is  far  more  easily  done  than  the  artery,  the  secretion  of  bile  is  seen  to 
stop;  but  the  experiment  which  suspends  the  abdominal  venous  circula- 
tion, is  too  speedily  fatal,  to  justify  any  conclusive  inference.  It  is  on 
analogical  proofs,  that  the  received  hypothesis  rests,  touching  the  man- 
ner of  the  biliary  secretion.  The  hepatic  artery,  remarkably  lessened  by 
the  branches  it  has  sent  off  in  its  way  towards  the  liver,  is  to  that  organ 
what  the  bronchial  arteries  are  to  the  lungs;  and  in  the  same  manner, 
the  branches  of  the  vena  portae,  spread  through  its  substance,  may  be 
compared  to  the  system  of  pulmonary  vessels.  It  is  still  to  be  confessed, 
however,  that  the  enormous  bulk  of  the  liver,  its  being  found  in  almost 
all  animals,  and  the  quantity  of  blood  carried  into  it  by  the  vena  portae, 
compared  to  the  small  secretion  there  is  of  bile,  lead  to  the  belief  that  the 
blood  sent  to  it  from  all  the  other  organs  of  digestion,  undergoes  changes 
there,  on  which  science  possesses,  as  yet,  no  certain  data,  though  the 
chemists  maintain,  that  the  liver  is,  in  some  sort  the  supplementary 
organ  of  the  lungs,  and  assists  in  clearing  the  blood  of  its  hydrogen  and 
carbon. 


*  "  Human  bile  differs  considerably  from  that  of  all  other  animals.  Its  colour  is 
sometimes  green,  sometimes  yellowish  brown,  aud  sometimes  it  is  nearly  colourless. 
Its  taste  is  not  very  bitter.  It  is  seldom  completely  liquid,  but  usually  contains  some 
yellow  matter  suspended  in  it.  When  evaporated  to  dryness,  it  leaves  a  brown  mat- 
ter amounting  to  about  1-1 1th  of  the  original  weight.  When  this  matter  is  calcined, 
it  yields  all  the  salts  which  are  to  be  found  in  the  bile.  All  the  acids  decompose  hu- 
man bile,  and  throw  down  a  copious  precipitate,  consisting  of  albumen  and  resin."-— 
Thomson's  Chemistry,  &c. 
The  following  is  the  analysis  of  human  bile  according  to  BERZEMUS  :— 

Water, 908-4 

Picromel, 80- 

Albumen, 3' 

Soda, 4-1 

Phosphate  of  lime,   .... 

Common  salt,  ....        3-4 

Phosphate  of  soda  with  some  lime,  1  • 

1000 

Copland. 


105 

This  nanle  of  venaportx  is  given  to  a  peculiar  venous  system,  enclosed 
in  the  abdominal  cavity,  and  formed  as  follows:  The  veins  which  bring 
back  the  blood  of  the  spleen,  and  the  pancreas,  of  the  stomach  and  intes- 
tinal canal,  are  united  in  a  very  large  trunk,  which  ascends  towards  the 
concave  face  of  the  liver,  and  there  divides  into  two"  branches*.  These 
lie  in  a  deep  fissure  in  the  substance  of  this  viscus;  they  send  out, 
through  all  its  thickness,  a  multitude  of  branches,  which  divide  like  ar- 
terial vessels,  and  end,  in  part,  by  opening  into  the  biliary  ducts  or  pores, 
and,  in  part,  by  producing  the  simple  hepatic  veins.  These  veins,  situ- 
ated chiefly  towards  the  convex  or  upper  surface  of  the  liver,  bring  back, 
into  the  course  of  the  circulation,  the  blood  which  has  not  been  employ- 
ed in  the  formation  of  bile,  and  that  which  has  not  served  to  nourish  the 
substance  of  the  liver:  for^  they  arise  equally  from  the  extremities  of 
the  vena  portae,  and  from  the  extremities  of  the  ramifications  of  the  he- 
patic arteryf. 

The  liver  differs  from  all  organs  of  secretion,  in  this,  that  the  materi- 
als of  the  fluid  it  elaborates,  are  not  supplied  to  it  by  its  arteries.  It 
should  seem  that  the  bile,  a  fat  and  oily  fluid,  in  which  hydrogen  and  car- 
bon predominate,  could  be  drawn  only  from  venous  blood,  in  which,  as  is 
known,  these  two  principles  are  in  superabundance.  The  blood  acquires 
the  venous  qualities,  as  it  passes  along  the  circuitous  course  of  the  circu- 
lation, and  is  supplied  with  hydrogen  and  carbon  the  more  fully,  the 
slower  it  flows.  Now,  it  is  easy  to  see,  that  all  is  naturally  disposed  for 
slackening  the  circulation  of  the  hepatic  blood,  and  to  give  it,  eminently, 
the  distinguishing  properties  of  venous  blood.  The  arteries  which  fur- 
rush  blood  to  the  organs,  in  whkh  the  vena  portae  rises,  are  either  verv 
flexuous  as  the  splenic,  or  frequently  anastomose,  like  the  arteries  of  the 
intestinal  tube,  which  of  all  that  are  in  the  body,  abound  most  in  visible 
divisions  and  anastomoses.  It  will  be  seen  in  the  chapter  on  circula- 
tion, how  well  these  dispositions  are  adapted  for  retarding  the  course 
of  the  arterial  blood.  Once  carried  into  the  organs  of  digestion,  the 
blood  stays  there,  whether  it  be  that  the  coats  of  the  hollow  viscera  be- 
ing collapsed  or  closed  upon  themselves,  hardly  yield  it  passage,  or 
that  the  organization  of  some  one  of  these  viscera  is  favourable  to  its 
stagnation. 

The  spleen  seems  to  serve  this  purpose.  Does  this  dingy  and  soft 
viscus,  lodged  in  the  left  hypocondrium,  and  attached  to  the  great  fundus 
of  the  stomach,  receive  the  blood  into  the  minute  cells  of  its  spongy  pa- 
renchyma, or  does  this  fluid  merely  traverse,  very  slowly,  the  delicate 
and  tortuous  ramifications  of  the  splenic  vessels?  In  other  respects,  there 
is  no  organ  that  exhibits  more  variety  of  number,  of  bulk,  of  figure,  of 
colour,  and  of  consistence.  Sometimes  manifold,  often  divided  into  se- 


*  Professor  Louis  JACOBSOX,  has  made  a  very  important  discovery  in  comparative  ana- 
tomy relative  to  a  venous  system  going-  to  the  kidneys,  analogous"  to  the  portal  system 
ofthe  liver.  A  translation  ofhis  Observations  has  been  published  in  the  Philadelphia 
Medical  Journal,  vol.  6,  p.  87.  We  have  satisfied  ourselves  of  his  con-ectness,  espe- 
cially by  an  examination  of  these  veins  in  the  sturgeon. — Godman, 

In  two  instances  the  vena  ports  has  been  found  running,  not  to  the  liver  but  di- 
rectly to  the  vena  cava  inferior.  One  of  these  is  described  by  Mr.  AHERNETHT,  in  Vol. 
LXXXI1I.  of  the  Philosophical  Transactions,  and  the  other  by  Mr.  LAWRENCE,  in  Vol. 
IV.  ofthe  Medico-Chirurgical  Transactions.—  Copland. 

For  some  observations  on  the  structure  and  actions  ofthe  liver,  see  APPENDIX 
M. 


veral  lobes  by  deep  clefts;  its  bulk  varies,  not  only  in  different  individu- 
als, but  even  in  the  same,  at  different  times  of  the  day,  as  the  stomach, 
full  or  empty,  admits  or  rejects  the  arterial  blood,  and  compresses  the 
spleen  between  its  large  extremity,  and  the  ribs  under  which  it  is  situa- 
ted, or  leaves  it  free. 

The  blood  which  fills  the  tissue  of  the  spleen,  blacker,  more  fluid,  rich- 
er in  oily  principles,  owes  all  these  qualities,  which  led  the  ancients  to 
consider  it  as  a  peculiar  substance,  called  by  them  the  atra  bilis,  or  black 
bile,  to  its  long  protracted  continuance  within  that  viscus*  The  branches, 
which  by  their  union  form  the  vena  portse,  have  thinner  parietes  than 
the  other  veins  of  the  body,  they  are  not  furnished  with  valves,  and  they 
do  not  readily  free  themselves  of  the  blood  which  fills  them.  The  action 
of  these  veins  is,  in  fact,  so  feeble,  that  it  would  not  suffice  to  enable 
them  to  carry  the  blood  onward,  if  the  gentle  and  alternate  compression 
of  the  diaphragm  and  abdominal  muscles  on  the  viscera  of  the  abdomen, 
did  not  favour  its  circulation.  On  reaching-  the  liver,  the  blood,  which 
is  highly  venous,  is  further  slackened  in  its  circulation,  by  the  increased 
dimensions  of  the  space  in  which  it  is  contained,  the  united  calibre  of 
the  branches  of  the  hepatic  vena  portae,  exceeding  considerably  that  of 
the  principal  trunk.  Besides,  these  vessels  are  enveloped  in  the  paren- 
chymatous  substance  of  the  liver,  and  can  act  but  feebly.  It,  therefore, 
circulates  slowly  through  that  organ,  and,  with  difficulty,  returns  into 
the  course  of  circulation.  The  hepatic  veins,  which  are  of  rather  con- 
siderable calibre,  and  without  valves,  remain  constantly  open,  their  pa- 
rietes cannot  close  and  contract  on  tlie  blood  which  fills  them,  on  account 
of  their  adhesion  to  the  parenchymatoixs  substance  of  the  liver.  They 
open  into  the  vena  cava,  very  near  the  place' at  which  that  vein  termi- 
nates in  the  right  auricle.  The  regurgitation  of  the  blood,  during 
the  contraction  of  that  cavity  of  the  heart,  is  fek  in  the  veins,  and  the 
blood  forced  back  towards  the  liver,  is  exposed  for  a  longer  time  to 
its  action. 

The  spleen,  therefore,  performs  only  preparatory  functions,  and  may 
he  considered  as  the  auxiliary  of  the  liver,  in  the  secretion  of  the  bile*. 
It  is  observed,  that  the  quantity  of  the  latter  increases,  after  the  spleen 
has  been  extirpated,  and  that  it  is  less  yellow,  less  bitter,  and  always  im- 
perfect. The  blood  which  circulates  in  the  omentum,  is  very  similar  to 
that  of  the  spleen;  I  would  even  say,  that  it  contains  oily  particles,  if 
the  drops  which  I  have  clearly  noticed  on  its  surface,  might  not  have 
come  from  the  adipose  tissue  of  the  omentum,  which  allows  the  fluid  con- 
tained in  its  cells  to  flow,  when  a  small  puncture  is  made  into  it,  in  exa- 
mining the  blood  contained  in  its  veins. 

The  bile  secreted  in  the  tissue  of  the  liver  f  is  absorbed  by  the  biliary 
ducts,  the  union  of  which  forms  the  hepatic  duct.  The  latter  issues  from 
the  concave  surface  of  the  liver,  and  conveys  the  bile,  either  immediately 
into  the  duodenum,  by  means  of  the  ductus  communis  choledochus,  or 
into  the  gall  bladder.  This  small  membranous  pouch,  which  adheres  by 
means  of  cellular  tissue  to  the  lower  surface  of  the  liver,  is  in  some  ani- 
mals entirely  distinct  from  that  organ,  and  connected  to  it,  only  by  the  in- 


*  On  the  subject  of  cystic  and  hepatic  bile,  the  student  will  do  well  to  consult  BICHAT 
on  tJie  membranes,  p.  61,  &c. — Godman. 

•j-  See  APPENDIX,  Note  N,  for  an  account  of  the  latest  observations  and  opinions 
respecting  the  structure  and  functions  of  the  spleen. — Copland. 


107 

sertion  of  its  duct,  into  that  which  comes  from  the  liver.  Its  inner  mem- 
brane is  soft,  fungous,  plicated,  and  always  covered  with  the  mucus,  se- 
creted by  the  glandular  criptae  which  it  contains.  This  mucus  defends 
the  gall  bladder  against  the  action  of  the  bile  which  it  contains.  The  al- 
most parallel  course  of  the  hepatic  and  cystic  ducts,  the  acute  angle  at 
which  they  meet,  renders  it  difficult  to  account  for  the  passage  of  the 
bile  into  the  gall  bladder.  It  appears,  that  when  the  duodenum  is  empty, 
the  bile  regurgitates,  in  part,  from  the  hepatic  duct  in  the  gall  bladder, 
collects  within  it,  becomes  thicker  and  yellower,  and  requires  a  greater 
degree  of  bitterness.  Consequently,  the  use  of  the  gall  bladder,  is  to  serve 
as  a  reservoir  to  a  portion  of  the  bile,  whiclj,  by  remaining  within  it,  is 
improved  in  quality,  acquires  consistence  and  bitterness,  and  is  heighten- 
ed in  colour,  by  the  absorption  of  its  fluid  parts*. 

XXVII.   The  irritation  produced  on  the  parictes  of  the  duodenum, 
when  distended  by  the  chyme,    is  propagated  to  the  gall  bladder,  by  the 
cystic  and  common  ducts.    Its  parietes  then  contract,  and  oblige  the  bile 
to  flow,  along  this  cystic  duct   into  the  ductus  commimis  choledochus. 
The  pressure  of  the  distended  intestines  on  the  gall  bladder,  favours  the 
excretion  of  bile.     The  hepatic  bile  is  also  more  abundantly  poured  into 
the  duodenum  during  digestion,  from  being  secreted  in  greater  quantity 
by  the  liver,  which  participates  in  the  irritation  affecting  the  organs  of 
digestion,  and  secretes  a  greater  quantity.     The  cystic  and  hepatic  bile, 
mixed  in  the  ductus  communis  choledochus,  undergoes  a  change  before 
entering  the  duodenum,  by  uniting  with  the  fluid  of  the  pancreas.     The 
excretory  duct  of  the  pancreas,  a  glandular  organ,  which,  in  structure, 
bears  so  great  an  analogy  to  the  parotid  glands,  thatsonje  physiologists, 
assuming  an  identity  of  functions,  have  called  it  the  abdominal  salivary 
gland,  joins  the  biliary  duct,  before  the  latter  c>pens  in  the  duodenum, 
after  having  insinuated  itself  obliquely  between  the  coats  of  that  intes- 
tine.    It  arises  within   the   pancreas,   from<t  great  number  of  radicles 
which  join  it,  like  the  feathers  of  a  quill  t»  a  common  trunk.    Its  calibre 
increases  in  size  as  it  approaches  the  l^ge  end  of  the  pancreas,  situated 
on  the  right,  in  the  concavity  of  the  pecond  curvature  of  the  duodenum. 
Nothing  precise  is  known,  with  regard  to  the  nature  of  the  pancreatic 
fluid ;  the  striking  resemblance  of  the  pancreas  to  the  salivary  glands 
leads  to  a  presumption,  that  t^s  fluid  bears  considerable  analogy  to  the 
saliva.     The    quantity  of  fluid  secreted    by  the   pancreas    is    likewise 
unknown,  but  it  must  be  considerable,  if  one  may  judge  from  the  great 
number  of  nerves  and  vessels  which  pervade  its  glandular  tissue,  and  its 
quantity  is,  most  probably,  increased  by  the  irritation  of  the  food  in  the 
duodenumf. 

*  See,  in  the  cliapteron  secretion,  the  laws  which  that  function  obeys. —  Copland. 

•\  Opinions  are  various  respecting  the  quantity  of  the  secreted  fluid  which  the  pan- 
creas yields.  AUTEXIUETII  reckoned  the  quantity  at  nine  ounces  tiie  twenty-four 
hours.  It  has  been  generally  supposed  that  this  secretion  is  considerably  augmented 
At  the  time  that  the  chyme  flows  into  the  duodenum ;  and  the  intimate  connexion 
existing1  between  the  ganglial  nerves,  supplying-  these  viscera,  favours  the  conclusion. 
MAGENDIE,  however,  rejects  this  inference,  and  inserts,  without  stating  the  grounds 
of  his  opinion,  that  the  flow  of  the  pancreatic  juice  is  least  abundant  during  digestion. 

The  disordered  functions  of  this  organ  appear  to  be  very  essentially  concerned  in 
the  production  of  some  diseases  which  are  too  often  referred  entirely  to  the  stomach 
and  small  intestines,  which,  no  doubt,  become  consecutively  deranged  from  this  cause  ; 
or,  if  the  actions  of  the  pancreas  be  not  primarily  diseased,  a  co-existent  disorder  may  be 
present  in  these  allied  viscera,  and  be  equally  the  result  of  one  cause. —  Copland. 


108 

This  combination  of  the  united  pancreatic  and  biliary  fluids  poured  on 
the  chyme,  penetrates  it,  renders  it  fluid,  anamalizes  it,  separates  the 
chylous  from  the  excrementitious  part,  and  precipitates  whatever  is  no: 
nutritious.  In  bringing  about  this  separation,  the  bile  itself  seems  to  be 
divided  into  two  parts,  its  oily,  coloured,  and  bitter  portion  passes  along 
Avith  the  excrements,  sheathes  them,  and  imparts  to  them  the  stimulating 
qualities  necessary  to  excite  the  action  of  the  digestive  tube.  Its  albu- 
minous and  saline  particles  combine  with  the  chyle,  become  incorporated 
lo  it,  are  absorbed  along  with  it,  and  return  into  the  circulation.  There 
may,  in  fact,  be  noticed  in  the  alimentary  mass,  after  it  has  undergone 
this  combination,  two  very  ^distinct  parts,  the  one  is  a  whitish  milky  sub- 
stance, which  swims  to  the  surface,  and  is  the  least  in  quantity  ?  the 
other  is  a  yellowish  pulp,  in  which,  when  digestion  is  healthy,  it  is  not 
easy  to  recognize  the  nature  of  the  food.  When  the  liver  is  obstructed, 
and  the  bile  does  not  flow  in  sufficient  quantity,  the  faeces  are  dry  and 
discoloured;  the  patients  are  troubled  with  obstinate  costiveness,  the 
excrement,  uncombined  with  the  bitte?  and  colouring  matter  of  the  bile, 
not  proving  sufficiently  irritating  to  the  intestinal  canal. 

We  have  just  mentioned  how  the  separationof  the  chyle  is  performed; 
but  the  mechanism  of  that  separation  and  the  process  of  chylification  are 
absolutely  unknown.  How  does  the  union  of  the  bile  to  the  chyme  ope- 
rate, in  extracting- from  the  latter  the  recrementitious  part,  and  in  making 
it  swim  above  the  rest?  Is  there  any  connexion  between  that  process  and 
the  nature  of  the  constituent  principles  of  the  bile  ?  The  knowledge  of 
the  composition  of  the  bile,  affords  as  little  assistance  in  the  explanation 
as  does  the  knoAviedge  of  the  chemical  properties  of  the  semen,  in  under- 
standing the  admirable  function  of  generation.  All  these  acts  of  the  ani- 
mal economy,  are  as  mysterious  and  inexplicable,  as  the  action  of  the 
brain  in  producing  thought,  a  phenomenon  which  so  many  physiologists 
have  considered  as  exceeding  the  power  of  matter,  and  for  which  they 
seem  to  have  reserved  all  th-oir  admiration,  though  nil  mirari,  which  I 
would  translate  by  wondering  at  nothing,  ought  to  be  the  motto  of  any  one 
-who  has  made  some  progress  in  ti-e  study  of  the  laws  of  life. 

XXVIII.  Of  the  action  of  the  smalt  Intestines.  After  remaining  a  certain 
time  within  the  duodenum,  the  alimentary  mass  decomposed  by  the  bile, 
or  rather  by  the  pancreatico-biliary  fluid  separated  into  two  parts,  the 
one  chylous,  the  other  excrementitious,  passes  into  the  jejunum  and 
ileum,  which  are  not  easily  distinguished  from  each  other,  and  which  dif- 
fer in  their  relative  length,  according  to  the  elements  on  which  anato- 
mists ground  the  distinction*. 


*  The  redness  of  the  parietes  of  the  jejunum,  the  empty  condition  of  that  intestine, 
its  situation  in  the  umblical  region,  the  great  number  of  its  valvulze  conniventea,  do  not 
distinguish  it  from  the  ileum,  for,  the  colour  of  the  intestinal  canal  varies  in  different 
parts  (/fits  extent,  and  the  substances  which  fill  it  are  found  in  different  parts  of  the 
canal,  according  to  the  progress  of  digestion  at  the  time  the  parts  are  examined ;  ac- 
cordin0'  as  the  convolutions  are  situated  within  the  cavity  of  the  pelvis,  or  rise  towards* 
the  epigastric  region ;  according  to  the  full  or  empty  state  of  the  bladder  and  stomach  -r 
and  the  number  of  circular  folds,  called  valvulse  conniventes,  diminishes,  as  on-e  gets- 
near  to  the  termination  of  the  ileum.  Winslow  got  over  the  difficulty,  by  considering; 
tile  upper  two-fifths  of  the  small  intestines  as  jejunum,  and  the  remaining  three-fifths 
as  ileum.  This  last  division,  from  measurement,  is  wholly  arbitrary,  and  is  besides 
useless,  for  there  is  not,  perhaps,  above  one  occasion  in  which  it  would  be  interesting 
to  distinguish  the  jejunum  from  the  ileum.  In  operating  for  hernia,  when  the  intes- 


The  jejunum  and  the  ileum  alone  occupy  nearly  three-fourths  of  the 
whole  length  of  the  digestive  canal ;  they  are  straiter  than  the  duodenum, 
and  do  not  dilate  so  readily,  because  the  peritoneum,  which  forms  their 
outer  covering,  lies  over  their  whole  surface,  with  the  exception  of  the 
posterior  border  at  which  their  vessels  and  nerves  enter.  It  is  along 
that  border,  that  they  are  fixed  to  the  mesentery,  a  membranous  band 
formed  by  a  duplicature  of  the  peritoneum,  which  contains  the  vessels 
and  nerves  going-  to  the  jejunum  and  ileum,  which  prevents  knots  from 
forming  in  the  intestines,  and  is  a  security  against  the  occurrence  of 
intus-susceptio.  It  is  well  known,  however,  that  in  some  rare  cases,  in- 
tus-susceptio  does  take  place,  with  utmost  danger,  of  the  patient's  life, 
who  generally  dies  in  the  agonies  of  insufferable  cholic  pains,  which 
nothing  can  alleviate.  The  progress  of  the  food,  along  the  small  in- 
testines, is  retarded  by  its  numerous  curvatures,  very  aptly  compared 
by  some  physiologists  to  the  windings  of  a  meandering  stream  which  fer- 
tilizes the  soil  it  waters.  These  numerous  convolutions  of  the  intestinal 
canal  favour  the  long  continued  presence  of  the  food  within  its  cavi- 
ty, so  that  the  chyle  expressed  from  the  excrementitious  part  by  the 
peristaltic  contractions  of  the  intestine,  may  present  itself  to  the  inha- 
ling mouths  of  the  lacteals,  by  which  it  is  to  be  absorbed.  These  chy- 
lous  absorbents  are  in  greater  number  on  the  surface  of  the  valvulae 
conniventes,  which  are  circular  folds  of  the  inner  membrane,  and  these 
are  at  a  greater  distance  from  each  other,  the  nearer  they  are  to  the  ter- 
mination of  the  ileum.  The  valvulae  conniventes  not  only  slacken  the 
progress  of  the  food,  but  by  their  projections,  they  sink  during  the  con- 
traction of  the  bowels,  into  the  alimentary  mass,  and  the  lacteals  on  their 
surface  take  up,  from  its  inmost  part,  the  chyle  which  they  are  destined 
to  absorb*. 

The  number  of  the  valvulae  conniventes  diminishes  with  that  of  the 
lymphatics.  The  progress  of  the  alimentary  substance  is  gradually  ac- 
celerated, as  it  parts  with  its  nutritive  and  recrementitious  particles.  A 
quantity  of  mucus,  secreted  by  the  internal  membrane  of  the  small  intes- 
tines, envelopes  the  chymous  mass  and  promotes  its  progress,  by  lubri- 
cating it :  this  intestinal  mucus  thrown  out  by  the  exhalant  arteries,  im- 
bues it,  renders  it  liquid,  and  adds  to  its  bulk.  This  fluid  which  seems  to 
partake  of  the  nature  of  albumen  and  gelatine,  and  to  hold  several  saline 
substances  in  solution,  is,  for  the  greater  part,  recrementitious,  and  must 
be  very  considerable  in  quantity,  if  we  may  judge  from  the  calibre  of  the 
mesenteric  arteries,  and  from  the  extent  of  the  internal  surface  of  the  in- 
testines. It  is,  however,  scarcely  possible,  that  this  exhalation  should 
amount  to  eight  pounds  in  twenty-four  hours,  according  to  Haller's  cal- 
culation, who,  as  we  shall  observe,  when  we  treat  of  the  secretions,  has 
generally  over-rated  their  amount. 

The  peristaltic  contractions,  by  the  assistance  of  which,  the  alimentary 
mass  is  sent  along  the  whole  course  of  the  small  intestines,  do  not  occur 
in  a  regular  and  uninterrupted  succession,  from  the  stomach  to  the 
coecum.  This  undulatory  and  vermicular  motion  manifests  itself  at  once, 

tine  is  mortified,  one  would  decide  the  more  readily  to  leave  an  artificial  anus,  if  one 
could  be  sure  that  the  gangrenous  portion  belonged  to  the  latter  intestine  ;  but  of  this 
it  is  absolutely  impossible  to  be  certain.— -.Star's  Note. 

*  See  APPENDIX,  Note  O,  for  some  remarks  respecting1  the  mucous  coat  of  the 
digestive  eaual,  and  the  functions  of"  the  small  and  large  intestines Copland. 


110 

in  several  points  of  the  length  of  the  tube,  whose  curvatures  straighten 
themselves  at  intervals.  In  this  action,  the  intestinal  curves  are  decom- 
posed into  a  great  number  of  short  straight  lines  which  meet,  so  as  to 
form  obtuse  angles.  The  peristaltic  motion  which  affects  the  muscular 
fibres  of  the  intestines,  is  caused  by  the  irritation  of  the  alimentary  sub- 
stance on  the  sentient  parietes  of  the  canal  along  which  it  descends,  to- 
wards the  great  intestines.  The  jejunum  and  the  ileum,  covered  by  the 
peritoneum,  except  at  the  part  which  connects  them  to  the  mesentery,  at 
the  time  of  dilatation,  separate  the  two  peritoneal  laminae,  forming  the 
mesentery.  They  occupy  the  space  between  the  branches  of  the  mesen- 
teric  vessels,  whose  last  division  is  always  at  some  distance  from  the  ad- 
hering edge  of  the  intestine.  If  this  division  of  the  vessels  had  taken 
place,  nearer  to  the  union  of  the  intestine  and  mesentery,  the  intestinal 
canal  would  not  have  admitted  of  dilatation,  without  stretching  the  ves- 
sels situated  at  the  angle  of  separation.  It  is  likewise  observed,  that  in 
the  portions  of  the  digestive  tube  which  are  most  susceptible  of  dilata- 
tion, the  last  vascular  divisions  are  most  distant.  Hence  the  left  gastro- 
epiploic  artery  is  always  at  a  greater  distance  from  the  great  curvature  of 
the  stomach,  than  the  right,  a  circumstance  of  which  no  anatomist  has 
hitherto  taken  notice. 

XXIX.  Of  Digestion  in  the  Great  Intestines.  The  alimentary  mass,  after 
it  has  parted  with  nearly  the  whole  of  its  nutritive  particles,  passes  from 
the  ileum  into  the  coecum ;  it  then  is  received  into  the  great  intestines, 
which  aie  more  spacious,  though  shorter,  than  the  small,  forming  scarce- 
ly, a  fifth  of  the  whole  length  of  the  digestive  tube. 

A  musculo-membranous  valvular  ring  is  placed  at  the  oblique  insertion 
of  the  ileum  into  the  first  of  the  great  intestines.  This  valve,  called  after 
Eustachius  or  Bauhinus,  who  are  considered  as  its  discoverers,  though 
the  merit  of  the  discovery  belongs  to  Fallopius,  is  formed  of  two  semi- 
circular segements,  the  right  edge  of  which  is  free,  and  floats  towards  the 
cavity  of  the  coecum.  The  more  the  parietes  of  that  intestine  are  dis- 
tended by  the  substances  which  it  contains,  the  greater  is  the  difficulty  to 
the  retrograde  flow  of  such  substances,  for  under  those  circumstances, 
the  two  extremities  of  the  valve  are  at  a  distance  from  each  other,  and 
its  edges,  which  are  free,  close  on  each  other,  like  those  of  a  button-hole 
whose  angles  are  drawn  in  opposite  directions;  besides,  the  muscular 
fibres  which  enter  into  its  structure,  render  it  capable  of  exerting  con- 
striction. It  is,  therefore,  calculated  to  permit  the  ready  flow  of  matter, 
from  the  ileum  into  the  coecum,  and  forcibly  prevent  their  return  in- 
to the  small  intestines.  There  are  facts  which  lead  to  a  belief,  that  its 
resistance  is  sometimes  overcome,  and  that  a  clyster,  thrown  in  with 
violence,  would  force  the  valve,  and  be  thrown  up  by  vomiting.  The 
great  intestines  may  be  considered  as  a  kind  of  reservoir  destined  to 
contain,  for  a  certain  time,  the  excrementitious  residue  of  our  solid  ali- 
ments, so  as  to  save  us  the  disgusting  inconvenience  of  constantly  part- 
ing with  it. 

As  the  peritoneum  does  not  wholly  cover  the  great  intestines,  they 
are  capable  of  considerable  dUitation,  and  of  extending  into  the  cellular 
substance  which  connects  them  to  the  posterior  part  of  the  abdomen. 
Their  muscular  coat  which,  in  a  manner,  is  the  base  of  the  intestinal 
tube,  does  not  consist  throughout,  of  circular  and  longitudinal  fibres.  The 
latter,  collected  into  fasciculi,  form  three  narrow  bands,  in  the  intervals 
of  which,  the  parietes  of  the  gut  are  exceedingly  weakened,  and  conse- 


Ill 

quently  capable  of  greater  extension.  These  longitudinal  fibres  being* 
besides,  shorter  than  the  intestine,  crease  it  transversely,  and  form  with- 
in it  a  number  of  cavities  and  cells,  marked  outwardly  by  prominences, 
separated  by  depressions.  If,  in  addition  to  the  peculiarities  of  struc- 
ture, it  be  considered,  that  in  the  ccecum  and  a  great  part  of  the  colon, 
the  contents  of  the  bowels  have  to  ascend  against  their  own  weight;  that 
the  curvature  forming  the  sigmoid  flexure  of  the  colon  is  very  considera- 
ble, and  that,  in  short,  (he  rectum  before  its  outer  termination  in  a  nar- 
row aperture,  is  considerably  dilated,  it  will  be  evident,  that  in  the  great 
intestines,  every  thing  tends  to  protract  the  stay  of  the  excrements. 

The  appenclicula  vermi-formis  of  the  coecurn  is,  in  man,  too  small  to 
perform  this  office;  in  the  herbivorous  quadrupeds,  in  which  it  is  much 
larger,  and  sometimes  not  single,  it  may  serve  as  a  reservoir  to  the  faecal 
matter.  Its  existence  merely  shows,  in  man,  an  analogy  to  those  animals 
in  which  it  is  truly  useful,  and  it  concurs  in  manifesting,  that  Nature,  in 
the  formation  of  particular  organs,  in  certain  kinds  of  animals,  aims  at  a 
mere  outline  which  she  fills  up  in  others,  to  show,  as  it  were,  that  there 
are  points  of  resemblance  between  all  beings  whom  she  has  gifted  with 
life  and  motion*. 

While  in  the  great  intestines,  the  alimentary  substance  becomes  mere- 
ly faecal,  by  parting  with  the  small  quantity  of  chyle  which  it  may  yet 
contain.  The  number  of  the  absorbents  decreases  progressively  from 
the  coecum  to  the  rectum ;  the  small  number  of  these  vessels,  accounts 
for  the  difficulty  of  throwing  in  nourishment  by  means  of  clysters,  when 
there  is  an  obstruction  to  deglutitionf.  The  excrements  thicken,  harden, 
and  become  formed  or  moulded,  in  the  cells  of  the  colon,  they  are  then 
urged  by  the  peristaltic  action,  into  the  rectum,  in  the  cavity  of  which 
they  accumulate,  till  they  excite  on  its  parietes  an  action  which  deter- 
mines their  expulsion. 

XXX.  Of  the  evacuation  of  the  faces.  When  a  call  to  evacuate  the  faeces 
is  experienced,  the  rectum  contracts,  while  the  diaphragm  descending, 
.and  the  abdominal  muscles  receding  towards  the  spinej,  thrust  the  vis- 
cera of  the  abdomen  towards  the  cavity  of  the  pelvis,  and  compress  the 
intestines  which  are  filled  with  fsecal  matter.  During  these  efforts,  the 
perineum  perceptibly  descends,  and  the  fibres  of  the  levator  ani  are 
somewhat  elongated.  The  combined  action  of  the  rectum  and  of  the 
abdominal  muscles,  overcomes  the  resistance  of  the  sphincters,  and  the 


*  The  number  of  these  appendages  is  very  great  in  some  of  the  interior  animals, 
especially  in  some  of  the  fishes.   See  Cuvier,  An.  Comp. — Godman- 

\  Some  physiologists  have  considered  as  unnecessary,  this  concurrent  action  of"  the 
diaphragm  and  abdominal  muscles ;  they  ground  their  opinion  on  the  circumstance, 
that  animals  whose  abdomen  has  been  laid  open  are  capable  of  voiding  their  faeces. 
Astruc,  one  of  the  luminaries  of  Montpellier,  denies  the  action  of  the  abdominal  mus- 
cles, in  the  efforts  which  one  makes  at  stool,  and  in  support  of  his  opinion,  he  brings 
forward  this  geometrical  proposition,  "  that  a  cord  disposed  in  the  form  of  a  circle, 
can,  by  contracting,  shorten  itself  in  an  infinitely  small  degree,  and,  therefore,  not 
perceptibly."  On  which  Pitcairn  humorously  enough  observes,  that  Astruc  had  never 
practised  what  he  reasons  upon :— ."  credo  Jlstrucciwn  nunquam  cacasse. — Jluthor's 
Note. 

*  Tliis  is  one,  but  not  the  only  reason,  why  the  system  cannot  be  sustained  for  any 
length  of  time  by  injections.    For  the  formation  of  chyle,  containing  the  elements  of 
blood,  which  it  always  does  when  genuine,  it  is  indispensably  necessary  that  the  aliment 
should  be  previously  converted  into  chyme,  an  operation  -which  seems,  from  experi- 
ments, cannot  be  effected  in  the  great  intestines. —  Chapman. 


its 

alvine  evacuation  takes  place,  and  is  facilitated  by  the  secretion  of  the 
mucous  follicles  of  the  rectum:  these  glands,  squeezed  by  the  pressure 
of  the  faeces,  pour  out  their  contents,  and  lubricate  the  circumference 
of  its  lower  aperture.  When  the  faeces  have  been  voided,  the  dia- 
phragm rises,  the  large  muscles  of  the  abdomen  cease  to  press  backwards 
and  downwards  upon  the  viscera  of  that  cavity;  the  perineum  ascends 
and  the  sphincters  close,  till  a  renewal  of  the  same  call,  again  brings  on 
the  same  action. 

The  call  to  avoid  the  fseces,  is  more  frequent  in  children  than  in  adults, 
because,  at  an  early  period  of  life,  the  sensibility  of  the  intestinal  canal 
is  greater,  the  contents  of  the  bowels  more  fluid,  and  digestion  more  ac- 
tive. As  we  advance  in  years,  sensibility  becoming  impaired,  and  con- 
tractility experiencing  a  proportionate  loss  of  power ;  the  secretions  be- 
ing, likewise,  less  abundant,  the  bowels  become  sluggish,  the  stools  more 
scanty  and  indurated.  They  are,  likewise,  less  frequent  and  copious  in 
women  than  in  men,  whether  it  be,  that  the  digestive  power  extracts 
from  the  aliment,  a  greater  proportion  of  nutritious  matter,  or  that  the 
menstrual  evacuation  being  a  kind  of  substitute  for  the  intestinal  secre- 
tions, less  remains  to  add  to  the  bulk  of  the  excrementitious  mass.  The 
evacuation  of  the  faeces  may  be  brought  on  by  throwing  liquids  into  the 
rectum,  which  dilute  the  faeces,  detach  them  from  the  parietes  of  the  in- 
testines, and,  exciting  on  these  parietes  an  irritation  to  which  they  are 
not  accustomed,  determine  their  contraction. 

The  fetor  of  the  excrements  depends  on  their  incipient  putrefaction 
in  the  great  intestines.  This  decomposition  is,  almost  always,  attended 
with  the  extrication  of  gases,  in  which  sulphurated  hydrogen  prevails. 
This  gas,  which  at  times  escapes,  and  which  at  others  impregnates  the 
faeces,  is  the  cause  of  the  black  colour  which  they  give  to  silver  exposed 
to  their  action.  One  may  recognize  in  the  excrements  the  colouring- 
matter  of  vegetables,  such  as  the  green  colour  of  spinage,  the  red  of  beet- 
root; one  may,  likewise,  find  among  them,  the  fibrous  parts  of  plants  and 
animals,  the  indurated  bark,  and  the  seeds  covered  with  their  husks. 
The  digestive  juices  have  so  little  action  on  husks,  that  seeds  which 
have  not  been  broken  down  by  the  organs  of  mastication,  frequently  con- 
tinue capable  of  vegetation. 

During  the  process  of  digestion,  the  food  contained  in  the  stomach  and 
intestines  absorbs  or  extricates  different  gases.  M.  Jurine,  of  Geneva, 
opened  the  body  of  a  maniac  who  had  been  dead  a  few  hours,  and  collect- 
ed the  gases  which  escaped;  he  observed,  that  the  proportion  of  oxygen 
and  carbonic  acid  diminishes  from  the  stomach  towards  the  great  intes- 
tines, while  on  the  contrary,  there  is,  in  these,  an  increased  proportion  of 
azote ;  that  hydrogen  is  more  abundant  in  the  great  than  in  the  small  in- 
testines, that  it  is  less  in  quantity  in  these  than  the  stomach*.  Do  the 
oxygen  and  azote  form  a  part  of  the  atmospherical  air  which  is  taken  in 
with  the  food  and  with  the  saliva,  and  which  is  disengaged  by  the  heat 
of  the  intestinal  canal  ?  Or  are  these  gases  the  result  of  the  decomposi- 
tion of  the  food  and  of  the  intestinal  fluids?  Besides,  may  not  the  gas 
contained  in  the  intestines  of  a  dead  body,  have  been  formed  at  the 
moment  of  death  ?  We  know  that  in  several  instances,  at  the  moment 
contractility  is  forsaking  our  organs,  the  intestines  become  distended  by 


*  See  APPENDIX,  Note  C. 


113 

gas  which  hastens  the  approach  of  death,  by  impeding  the  descent  of  the 
diaphragm. 

Digestion,  when  healthy,  is  unaccompanied  by  the  production  of  gases. 
In  indigestion,  there  almost  always  escapes  carbonated  or  sulphureted 
hydrogen  gas,  which  produces  the  offensive  smell  of  the  air  which  es- 
capes at  the  anus:  this  smell  is  different  from  that  of  the  flatus  which  are 
brought  upwards,  these  contain  pure  hydrogen  or  carbonic  acid  gas.  The 
latter  is,  likewise,  sometimes  voided  by  the  rectum,  but  less  frequently 
than  hydrogen  combined  with  carbon,  sulphur,  or  even  phosphorus.  Is 
not  ammonia  itself  extricated,  and  does  it  not  accompany  the  evacuation 
of  the  faeces  in  certain  putrid  diarrhoeas,  as  indysg|tery  combined  with 
low  fever  ?  Though  the  formation  of  this  gas  implies  a  putrefactive  mo- 
tion opposed  to  the  vital  principle,  may  not  this  decomposition  com- 
mence in  substances  lying  in  the  great  intestines,  when  these  are  be- 
come almost  inert  from  the  impaired  condition  of  the  vital  power.  This 
would  riot  be  the  only  instance  of  a  chemical  process  taking  place  in  the 
intestinal  canal,  notwithstanding  the  counteracting  influence  of  vitality. 
Thus,  on  some  occasions,  grapes  eaten  in  too  great  quantity,  ferment  and 
produce  carbonic  acid  gas,  in  such  abundance,  that  this  elastic  fluid  over- 
comes the  resistance  of  the  intestines.  This  is  the  kind  of  distension 
from  flatulence  which  is  cured  by  drinking  plentifully  of  cold  water, 
which  dissolves  the  gas  naturally  soluble  in  that  fluid. 

XXXI.  Of  f/ie  secretion  and  excretion  of  the  Urine.     The  fluids  absorb- 
ed with  the  chyle,  and  taken  up  by  the  lymphatics  of  the  intestinal  tube, 
dilute  the  nutritive  part  extracted  from  the  solid  aliment,  and  serve  it  as 
a  vehicle.     When  they  have  reached  the  mass  of  the  bfood,  they  increase 
its  quantity,  diminish  its  viscidity,  and  render  it  more  fluid  ;  going  along 
with  it  throughout  the  whole  course  of  the  circulation,  they  supply  moist- 
ure to  all  the  parts  of  the  body,  and  become  loaded  with  the  molecules 
detached  from  them  by  the  vital  motion.     Then,  conveyed  to  the  urinary 
organs,  they  become  disengaged  from  the  rest  of  the  fluids,  carrying 
along  with  them  a  number  of  products  of  every  kind,  which  by  a  longer 
stay  in  the  animal  economy,  would  not  fail  to  occasion  a  manifest  distur- 
bance in  the  exercise  of  the  functions. 

XXXII.  The  rapidity  with  which  we  void,  with  the  urine,  certain  diu- 
retics, has  induced  several  physiologists  to  think,  that  there  exists  a  di- 
rect communication  between  the  stomach  and  bladder:  no  one,  however, 
has  ever  succeeded  in   pointing  out  those  peculiar  ducts,  which  might 
serve  to  convey  the  urine  from  the  stomach  to  the  urinary  organs,  with- 
out taking  the  circuitous  course  of  absorption  and  of  the  circulation,  and, 
besides,  the  learned  Haller  has  proved,  by  accurate  calculations,  that  the 
size  of  the  renal  arteries, 'whose  calibre  amounts  to  an  eighth  of  that  of 
the  aorta,  and  the  quickness  with  which  che  blood  flows,  sufficed  to  ac- 
count for  the  shortness  of  the  time  in  v-nich  certain  fluids  reach  the  uri- 
nary organs*. 

*  The  experiments  of  Dxnwnr  wit*  the  nitrate  of  potash,  and  of  BRAND B  with  the 
prussiate  of  potash,  have  led  severs'*  i'1  modern  times,  and  amongst  these,  Sir  EVERARD 
HOME,  to  support  the  opinion  allied  to  above.  MAGENDIE  made  experiments  in  order 
to  ascertain  this  matter,  and  deuced  from  them  the  following  inferences  :— 

1.  Whenever  the  prussiate  of  potash  is  injected  into  the  veins,  or  absorbed  from  the 
Intestinal  canal,  or  from  a  jerous  surface,  it  passes  quickly  into  the  bladder,  where  it 
may  be  easily  recognized  m  the  urine.  2.  Whenever  a  very  considerable  quantity  of 

P 


114 

A  thousand  ounces  of  blood  pass  through  the  renal  tissue  in  the  space 
of  an  hour :  supposing  that  this  fluid  contains  only  a  tenth  of  the  materi- 
als fit  for  supplying  urine,  a  hundred  ounces,  or  seven  pounds  and  a  quar- 
ter, may  be  given  out  in  this  short  time;  and  never,  with  the  most  co- 
pious and  diuretic  drinks,  does  more  of  it  pass  in  an  hour.  We  shall 
see,  however,  in  treating  of  absorption,  that  it  is  not  absolutely  impossi- 
ble, that  by  means  of  the  numerous  anastomoses  of  the  lymphatics,  this 
set  of  vessels  may  carry  a  liquid,  directly  from  the  stomach  into  the  blad- 
der. It  would  be  superfluous  to  mention,  in  this  place,  the  varieties  ob- 
servable in  the  kidneys,  in  point  of  number,  size,  and  situation.  These 
two  lobular  viscera,xomposed  of  the  union  from  twelve  to  fifteen  glan- 
dular bodies,  divided  in  the  foetus,  and  in  some  quadrupeds,  attached  to 
the  posterior  part  of  the  abdomen,  behind  the  peritoneum,  are  surround- 
ed with  a  cellular  covering  of  different  thickness,  and  particularly  remark- 
able by  the  consistence,  approaching  to  that  of  tallow,  of  the  fat  which 
fills  its  cells. 

If  ever  the  art  of  man  shall  penetrate  into  the  mystery  of  the  intimate 
structure  of  our  organs,  it  seems  probable  that  the  kidneys  will  furnish 
the  first  solution  of  the  problem*.  Even  coarse  injections  pass  readily 

the  prussiate  is  injected,  it  can  be  detected  in  the  blood  by  means  of  re-agents ;  but 
when  the  quantity  is  small,  it  is  impossible  to  discover  its  presence  by  any  of  the  usual 
tests.  3.  That  the  same  thing  takes  place  if  the  prussiate  be  mixed  with  blood  in  a 
vessel.  4.  That  this  salt  may  be  detected  in  the  urine  in  any  proportion,  and  therefore 
it  is  by  no  means  extraordinary,  that  DARWIW  and  BRAJTIJE  could  not  find  in  the  blood 
a  substance  which  they  easily  perceived  in  the  urine.  Mag.  Phys.  Vol.  II.  p.  380. 

The  existence  of  absorbent  vessels  which  open  into  veins  along  their  smaller  ramifi- 
cations, and  even  towards  their  terminations,  and  the  frequent  anastomoses  of  the  form- 
er set  of  vessels  with  the  latter,  all  which  appears  to  be  satisfactorily  shown,  (See  AP- 
PENDIX, Note  Q.)  sufficiently  explain  the  rapid  transit  of  liquids,  or  other  substances, 
from  the  stomach  and  other  parts  of  the  bo6y  into  the  circulating  fluid,  and  their  quick, 
but  subsequent,  appearance  in  the  secretions, 

In  consequence  of  the  activity  of  those  secreting  organs  whose  chief  function  it  is  to 
remove  substances  from  the  blood,  which  would  become  deleterious  from  their  accu- 
mulation in  it,  and  owing  to  the  stimulus  which  such  substances  give  these  organs  when 
conveyed  to  them  in  the  course  of  the  circulation,  they  are  eliminated  from  the  blood 
as  last  as  they  enter  it,  so  that  they  seldom  can  be  present  in  sufficient  quantity  to  be 
detected  by  the  usual  chemical  agents.  Copland. 

*  One  of  the  latest  and  most  minute  dissections  of  the  kidney,  has  been  made  by 
EYSENHABDT,  of  Berlin,  (De  structura  renum  Observationes  Anatomies,  Ber.  1818, 
4to.  His  observations  were  made  on  very  thin  slices  of  the  kidney  cut  longitudinally, 
and  also  in  the  short  diametet :  these  were  wetted  with  diluted  alcohol,  and  examined 
in  the  microscope.  •«  The  experiments  were  originally  made  to  discover  the  peculi- 
arity, it  any,  of  a  diabetic  kidnev;  but  no  perceptible  difference  was  found  to  exist  be- 
tween the  diabetic  and  healthy  sttte  of  this  organ. 

«  The  naked  eye  discovered  sm*i  p0mts  On  these  slices,  which  the  microscope  re- 
psesented  as  oval  and  sometimes  rtnnd  granulations,  situated  at  different  distances 
from  each  other,  and  varying  in  size,  i^th  in  the  same  kidney  and  in  the  kidneys  of 
different  sexes.  After  maceration,  thesx  g^n9  couid  be  detached  with  their  adher- 
ing vessels,  and  a  void  was  left.  They  wye  composed  of  knotty  vessels,  surrounded 
by  an  ash-grey  substance,  and  united,  not  j*,  much  by  frequent  anastomoses,  as  by 
numerous  meetings  with  each  other.  The  a^.coloured  substance  was  not  granular; 
it  appeared  as  if  traced  with  *  pencil.  Injectio,  by  the  renal  artery  made  these  cor- 
puscules wholly  red ;  but  still,  some  deeper  and  e\her  clearer  points  could  be  perceiv- 
ed in  them.  Dr.  E.  considered  these  corpuscules  u  be  the  glandules  and  glomerules 
of  MALPIGHI  and  of  SCHUMLANSKY.  He  could  not  tnce  the  veins  arising  from  these 
glandules ;  but  he  refers  to  an  observation  of  PIIOCHASCR<,  in  which  a  successful  injec- 
tion of  the  renal  vein  showed,  under  the  microscope,  a  \<?.ry  loose,  vascular  little  net, 
surrounding  the  isolated  corpuscules  of  the  cortical  substanc<  "  Dr.  Mapes,  of  Frank- 


115 

from  the  renal  arteries  into  the  ureters,  or  excretory  ducts  of  the  kid- 
neys ;  a  convincing  proof  of  immediate  communication  among  theminute 
arteries,  which  exceedingly  tortuous  form,  with  the  minute  veins,  the 
cortical  or  outward  substance  of  the  kidneys,  and  the  straight  urinaey 
tubes,  which  distributed  in  conical  fasiculi,  in  the  interior  of  these  or- 
gans, constitute  what  has  been  called  its  tubuli  and  papillae.  The  passage 
of  injections  from  the  arteries  into  the  renal  veins,  is  as  easy  ;  and  I  have 
often  seen  the  coarsest  liquids  flowing  at  once  by  the  ureters  and  by  the 
emulgent  veins.  This  free  communication  between  the  arteries,  the 
veins,  and  excretory  ducts  of  the  kidneys,  gives  an  idea  of  the  ra- 
pidity with  which  the  blood  must  flow  through  these  organs,  whose 
firm  consistence  allows  a  very  moderate  dilatation  io  the  vessels ;  and 
suggests  the  possibility  of  a  sort  of  filtration  of  the  urinary  fluid,  the  se- 
cretion of  which  would  be  only  succession  of  chemical  or  mechanical  se- 
parations, from  the  blood,  in  its  passage  along  very  minute  ducts,  of  a 
bore  progressively  decreasing.  This  was  the  opinion,  at  least,  of  Ruysch, 
whose  system  on  the  intimate  composition  of  our  organs,  and  on  the  im- 
mediate continuation  of  the  blood-vessels  with  the  excretory  ducts  is 
chiefly  founded  on  the  facts  of  structure,  discovered  to  him  by  his  beauti- 
ful injections  of  the  renal  arteries. 

The  kidneys  are  of  duller  sensibility,  and  less  energetic  action  than  the 
other  glands.  The  force  of  life  has  less  to  do  in  their  secretion,  and  their 
functions  may  be  more  readily  explained  on  the  principles  of  chemistry 
or  hydraulics. 

XXXIII.   If  we  attempt,  indeed,  to  apply  to  the  urinary  organs  the 
fundamental  laws  on  the  mechanism  of  secretions*,  it  is  not  seen,  that 
these  organs  are  not  under  their  absolute  controul.     Of  all  the  animal 
fluids,  urine  is  the  one  most  complex  in  its  elements,  and  most  variable  in 
its  qualities.     Not  only  do  foreign  substances-  sometimes  appear  in  it,  af- 
feet,  and  even  change  its  composition;  other  fluids  may,  at  times*  J*ix 
with  it,  and  disguise  it  altogether.  Thus  credible  observers  tells  us 
appearance  of  urine,  of  bile,  fat,  milk,  blood,  pus*  of  which  m^v 
may  be  found  collected  in  Mailer's  great  work  on  physiology,    The  kid- 
neys, then,  have  less  sensibility  than  the  other  secretory  organs :  they 
reason  less,  if  I  may  venture  on  the  expression,  on  these^at^onPro^uced 
by  the  various  substances  in  the  blood  :  their  action^  also  less  power- 
•j» Z. . 

fort  on  the  Maine,  says,  that  he  has  seen  exactly  this  st^ct.ure.. from  injections  of  the 
hepatic  vein,  and  therefore  he  infers  that  the  anatonv  ot  tne  Ilver  and  kidney  may  be 
similar  in  other  respects. 

From  these  glandules,  EYSENUARBT  says'  "  t^1  tne  g^yish  and  transparent  urini- 
ferous  vessels,  which  seem  to  be  articulated,  *'lse-  Tnese  vessels  form  a  net-work, 
which  every  where  unites  the  glandules  witb~ach  other-  He  therefore  thinks  SCHUM- 
I.ANSKT  was  deceived,  in  supposing  that  -ach  glandule  had  a  secretory  duct,  which, 
after  making  numerous  curves,  ran  strait  into  the  medullary  substance. 

"  Little  precise  information  is  give*  b7  EITSENHABDT  respecting  the  medullary  part. 
The  excretory  ducts,  however,  whir1  "become  straight  when  they  pass  out  of  the  corti- 
cal substance,  pass  along  in  fascic^1  °f  about  twenty  in  each  fasciculus. 

"  In  a  foetus,  the  cortical  substance  was  smaller  in  proportion,  and  the  glandules  were 
of  scarcely  half  the  size.  Eac*  vascular  vessel  of  the  medullary  substance  was  com- 
posed of  granulations ;  some°f  them  being  voluminous,  and  others  much  smaller,  and 
all  strongly  pressed  against  each  other,  so  that  the  vessels  could  no  longer  be  distin- 
guished from  each  other,  but  their  passage  only  marked  by  striae.  The  granules  were 
not  produced  by  putrefaction,  although  putrefaction  gives  a  globular  appearance  to 
these  parts." — Copland. 

*  See  the  Chapter  on  Secretion* 


116 

ful ;  it  does  not  so  intimately  affect  the  fluid  subjected  to  it.  It  does  not 
change  the  heterogeneous  qualities  of  those  that  are  mixed  with  it,  and 
allows  them  to  pass  in  a  pure  state*. 

This  multitude  of  elements  in  the  composition  of  urine,  had  surely 
been  understood  by  the  ancients,  before  it  was  demonstrated  by  modern 
chemistry  :  ibrthey  considered  it  as  a  sort  of  extract  of  animal  substance, 
as  a  real  lixivium,  carrying  off  all  that  is  impure  in  the  economy,  and 
gave  it  the  name  of  lotium^  which  indicates  that  destination. 

Finally,  the  secretion  of  urine  is  more  uniformly  carried  on  :  it  is  con- 
tinual, or  at  least,  does  not  exhibit  so  prominently  those  alterations  of  ac- 
tion and  repose,  so  apparent  in  the  work  of  the  other  secretory  organs. 
When,  in  a  case  of  retention  of  urine,  we  introduce  a  catheter  into  the 
urinary  bladder,  and  leave  it  there,  the  urine  keeps  dropping  continually, 
and  would  wet  the  patient's  bed,  if  the  orifice  of  the  catheter  were  not 
kept  closed.  In  the  Memoirs  of  the  Academy  of  Sciences  for  the  year 
1761,  there  is  related  a  case  of  singular  conformation  of  the  urinary 
bladder.  This  musculo-membranous  viscus  protruded  through  an  open- 
ing at  the  lower  part  of  the  linea  alba,  and  was  turned  inside  out,  so  as  to 
present  externally,  its  mucuous  membrane.  This  case  afforded  an  oppor- 
tunity of  observing  the  continual  flow  of  the  urine  through  the  orifices  of 
the  ureters,  and  of  ascertaining  the  different  circumstances  attending  this 
process,  either  with  regard  to  the  qualities  of  this  fluid  or  to  the  quantity 
which  might  be  voided,  in  a  certain  space  of  time ;  and  in  this  respect, 
there  was  a  good  deal  of  difference,  according  to  the  state  of  sleep  and 
waking,  to  the  quantity,  and  to  the  diuretic  qualities  of  the  drink. 

The  urine  contained  in  the  ureters  is  turbid  and  imperfect  $  its  consti- 
tuent parts  are  not  thoroughly  blended  together,  as  may  be  observed,  if 
made  to  flow,  by  compressing  the  kidneys  in  a  dead  body.     It  improves 
by   passing  along  those  ducts,  acquires  the  characteristic  qualities  of 
ui'ne,  oozes  at  the  surface  of  the  papillae,  and  flows  into  the  membranous 
c allies  which  embrace  the  rounded  terminations  of  the  tubuli  uriniferi. 
The  uiJQt)  Of  the  calices  forms  the  pelvis,  or  the  expanded  portion  of  the 
ureters,  o,  membranous  ducts,  along  which  the  urine  is  incessantly  flow- 
ing into  the  1^^^.    The  urine  flows  into  the  bladder  by  its  own  weight, 
and  especially  \v  tne  action  of  the  parietes  of  the  ureters,  which  possess 


*  This  opinion  is  very  r,fferent  from  that  entertained  by  Dr.  THOMSON.  He  conceives 
that  it  is  not  merely  the  abs,.,action  o{  a  quantity  of  water  and  of  salts  accumulated  in 
the  blood  which  the  kidneys  p  ,,forn%  bm  that  a  chemical  change  is  produced  by  them, 
either  upon  the  whole  blood,  or  t  least  upon  some  important  part  of  it.  In  proof  of 
this  additional  function,  he  adduce.  the  wmat;on  of  nephrin  and  uric  acid,  as  he  sup- 
poses,  in  the  kidneys.  These  two  ^stances,"  he  says,  «  are  formed  in  the  kidneys, 
and  as  they  are  thrown  out,  after  ben,t  formed,  without  being  applied  to  any  useful 
purpose,  they  are  certainly  not  formed  m  ve  kidneys  for  their  own  sake.  Some  part 
of  the  blood  then  must  be  decomposed  in  tlKkidnev>  and  anew  substance,  or  substan- 
ces, must  be  formed  ;  and  the  urea  and  uric  ac^  must  j-,e  formed  at  the  same  time,  in 
consequence  ot  the  combined  action  of  the  aflim:es  whicii  produce  the  change  on  the 
blood ;  and  being  useless,  they  are  thrown  out  togvtner  with  a  quantity  of  water  and 
stilts,  which  in  all  probability  were  useful  in  bringjn,  about  the  changes  which  take 
place  in  the  arteries  and  in  the  kidneys,  but  which  areno  longer  of  any  service  after 
these  changes  are  brought  about.  Thorn.  Vol.  IV.  p.  62. 

This  reasoning  rests  entirely  on  the  assumption  that  those  substances  are  actually 
formed  in  the  kidneys  ;  it  is  quite  as  probable  that  they  are  produced  in  other  parts  of 
the  body,  and  are,  with  other  substances,  removed  from  the  blood  by  the  action  of 
those  organs.  See  APPENDIX,  Note  P,  for  some  experiments  and  further  observa- 
tions in  support  of  the  latter  opinion. —  Copland. 


117 

a  certain  degree  of  contractility.  To  the  above  causes,  may  be  added  the 
concussions  excited  by  the  pulsations  of  the  renal  arteries,  behind  which 
the  pelvis  of  the  kidney  is  situated,  and  by  the  pulsations  of  the  iliac  ar- 
teries, in  front  of  which  the  ureter  passes,  before  entering  the  cavity  of 
the  pelvis  ;  the  alternate  compression  from  the  viscera  of  the  abdomen, 
during  the  motions  of  respiration  ;  the  concussion  attending  bodily  exer- 
cise, as  riding  on  horseback,  walking,  running,  Sec. ;  the  pressure  of  the 
column  of  urine  from  the  kidneys,  and  the  want  of  resistance  towards  the 
bladder. 

XXXIV.  The  urine  is  continually  passing,  in  drops,  into  the  bladder, 
it  separates  its  parietes,  without,  however,  exciting  in  them  any  percepti- 
ble impression,  as  they  are  accustomed  to  its  stimulus.  The  urine  cannot 
accumulate  in  the  musculo-membranous  cavity  of  the  bladder*,  which  is 
situated,  exterior  to  the  peritoneum,  in  the  cavity  of  the  pelvis,  behind  the 
pubis,  above  which,  in  the  adult,  it  never  rises,  except  when  excessively 
distended,  unless  it  is  prevented  from  flowing  along  the  urethra,  or  from 
returning  by  the  ureters.  This  retrograde  flow  is  prevented  by  the  ob- 
lique insertion  of  these  ducts,  which  pass,  for  some  distance,  between  the 
muscular  and  mucous  coats  of  the  bladder,  before  opening  within  it,  to- 
wards the  posterior  angles  of  the  vesicaltrianglef,  by  openings  of  smaller 
dimensions  than  their  cavity.  The  inner  coat  of  the  bladder,  raised  over 
these  apertures,  gives  them  the  appearance  of  being  provided  with  valves, 
which  fit  the  better  these  orifices,  according  as  the  urine  contained  in  the 
bladder,  by  separating  its  parietes,  presses  against  each  other  the  coats 
by  which  they  are  formed,  and  between  which  the  ureters  pass,  along  a 
space  of  from  seven  to  eight  lines. 

The  urine  which  flows  into  the  bladder,  requires  a  certain  degree  of 
force,  to  separate  its  parietes  on  which  the  weight  of  the  intestines  press- 
es. This  is  effected  by  no  other  power,  than  by  that  which  causes  the 
flow  of  the  urine  along  the  ureters,  and  though  inconsiderable,  it  will  ap- 
pear sufficient,  if  it  be  considered  that  the  fluids  which  pass  from  a  strait 
channel  into  a  larger  cavity,  act  on  every  superficial  portion  of  its  parietes 
equal  to  the  area  of  the  channel,  with  a  power  equal  to  that  which  deter- 
mines their  flow  into  the  latter;  so  that  if  the  urine  descends  along  the 
ureters,  with  a  degree  of  force  equal  to  one,  and  if  the  inner  surface  of 
the  bladder  is  a  thousand  times  more  extensive  than  the  area  of  the  ure- 
ters, the  power  will  be  multiplied  a  thousand  fold. 

This  purely  mathematical  proposition  is  expressed  by  saying,  that  the 


*  In  the  numerous  tribe  of  birds,  the  bjfedder  is  wanting.  In  them,  the  ureters  open 
into  the  cloaca,  a  musculo-membranous  bag,  which  supplies  the  place  of  the  rectum, 
bladder,  and  uterus,  and  which  serves  as  a  reservoir  to  the  solid  excrements,  to  the 
urine,  and  to  the  eggs  detached  from  the  ovaria.  The  urine  of  birds  dilutes  the  faces, 
and  furnishes  the  carbonate  of  lime  which  forms  the  basis  of  the  egg-shell.  It  has  such 
a  tendency  to  concretion,  that  1  have  always  observed,  in  dissecting  various  fowls  of 
different  kinds,  an  earthy,  saline,  or  crystallized  substance,  forming  white  striae  easily 
seen  in  the  fluid  of  the  ureters,  through  their  skin  and  transparent  coats.  Hence  one 
may  readily  conceive,  how  frequently  calculi  would  form  in  these  animals,  if  their 
urine  accumulated  and  remained,  for  any  length  of  time,  stationary  in  a  cavity  destined 
to  contain  it Jluthor's  Note. 

|  The  French  anatomists  give  the  name  of  trigone  -vesicae,  to  that  portion  of  the 
bladder,  included  between  the  openings  of  the  ureters  and  the  neck  of  the  bladder, 
and  forming  a  triangle,  whose  base  is  represented  by  a  line  drawn  from  the  opening  of 
one  ureter  to  the  other,  and  whose  apex  is  situated  at  the  insertion  of  the  urethra  into 
the  neck  of  the  bladder. — Translator. 


113 

force  with  which  the  urine  passes  along  the  ureters,  is  to  that  by  whicis 
the  parietes  of  the  bladder  are  distended,  as  the  calibre  of  the  ureters  is  to 
the  superficies  of  the  bladder. 

The  pressure  which  the  urine,  accumulated  within  the  bladder,  exerts 
on  the  lower  part  of  the  ureters,  does  not  prevent  the  force  which  deter- 
mines its  descent  along  the  ureters,  from  carrying  it  into  the  bladder: — 
for,  the  column  which  descends  along  the  ureters,  being  higher  than  that 
contained  in  the  bladder,  these  two  organs  represent  an  inverted  syphon, 
the  longer  branch  of  which  is  represented  by  the  ureter. 

The  following  are  the  causes  which  enable  the  bladder  to  retain  the 
urine:  the  contraction  of  its  sphincter,  a  muscular  ring  surrounding  the 
termination  of  the  urethra  into  the  bladder:  the  angle  formed  by  that 
canal,  after  it  leaves  the  bladder;  and  lastly,  the  action  of  the  anterior 
fibres  of  the  levator  ani,  which  surround  the  neck  of  that  organ,  surround- 
ed besides  and  supported  by  the  prostate  gland.  These  fibres,  which 
are  calculated  to  compress  the  prostate  over  the  neck  of  the  bladder,  and 
to  raise  the  latter  against  the  pubis,  have  been  called  by  Morgagni,  fisettdo 
sphincteres  vesicse. 

The  urine,  deposited  by  drops  into  the  bladder,  gradually  separates  its 
parietes.  This  musculo-membranous  organ  rises,  and  at  the  same  time, 
carries  upwards  the  convolutions  of  the  ileum,  and  the  peritoneum  before 
which  it  lies,  behind  the  pubis  and  the  recti  muscles  with  which  it  is  in 
immediate  contact.  These  relations  of  the  peritoneum  to  the  distended 
bladder,  account  for  the  possibility  of  puncturing  it  above  the  pubis,  so 
as  to  let  out  an  accumulation  of  urine,  without  penetrating  into  the  cavi- 
ty of  the  peritoneum.  The  urine  remains  a  certain  time  in  the  bladder, 
according  to  the  capacity  of  the  latter,  to  the  irritability  and  extensibility 
of  its  parietes,  and  according  to  the  acrid  or  stimulating  qualities  of  the 
fluid  itself.  Thus  in  old  men,  in  whom  the  bladder  has  but  a  small  de- 
gree of  irritability  and  contractility,  the  urine  is  voided  less  frequently; 
it  accumulates  in  greater  quantity,  and  is,  at  times,  evacuated  with  diffi- 
culty. The  use  of  diuretics,  especially  of  cantharides,  renders  the  urine 
more  stimulating,  it  excites  powerfully  the  parietes  of  the  bladder,  and 
incessantly  stimulates  it  to  contraction.  Every  cause  of  irritation  seated 
within  the  bladder  itself,  or  in  its  vicinity,  renders  more  frequent  the 
calls  to  void  urine.  This  is  observed  in  cases  of  stone  in  the  bladder,  of 
piles,  gonorrhsea,  See.  The  urine,  while  in  the  bladder,  becomes  thicker 
from  the  absorption  of  its  more  fluid  parts,  its  elements  become  more 
intimately  blended,  sometimes  even,  it  appears  to  undergo  a  certain  de- 
gree of  decomposition. 

XXXV.  When,  either  by  the  extension  which  the  urine  occasions  in 
the  muscular  fibres  of  the  bladder,  or  by  the  irritation  which  it  excites 
in  the  nerves  distributed  on  its  inner  membrane,  we  experience  in  the 
pelvis  a  sensation  of  weight,  together  with  a  kind  of  tenesmus,  which,  as 
it  extends  along  the  urethra,  warns  us  to  void  urine;  then  we  bring  on  a 
contraction  of  the  bladder,  and  joining  to  its  action,  that  of  the  abdomi- 
nal muscles  and  of  the  diaphragm,  .we  expel  the  urine  by  a  process  very 
similar  to  that  of  the  excretion  of  the  faeces,  (XXIX.)  It  should  be  ob- 
served, however,  that  in  a  healthy  state  of  the  parts,  this  assistance  is 
required,  only  to  overcome  the  equilibrium  between  the  contractions  of 
the  bladder,  and  the  resistance  which  the  cause  of  retention  opposes  to 
the  evacuation  of  the  urine.  After  the  simultaneous  contraction  of  the 
diaphragm  and  abdominal  muscles,  to  press  down  the  intestines  on  the 


119 

bladder,  and  to  determine  the  first  flow  of  the  urine,  \ve  cease  that  effort, 
and  the  bladder  alone,  still  supported  by  the  weight  of  the  surrounding 
viscera,  which  compress  it  as  it  empties  itself,  completes  the  evacua- 
tion. We  repeat  the  first  effort,  only  in  case  we  wish  to  accelerate  the 
flow  of  the  urine.  In  the  evacuation  of  the  faeces,  on  the  contrary,  the 
muscular  coat  of  the  rectum  requires  the  incessant  co-operation  of  the 
respiratory  powers,  as  these  solid  substances  are  evacuated  with  more 
effort  than  the  urine.  To  prove,  beyond  a  doubt,  that  the  urine  is  evacu- 
ated, chiefly  by  the  action  of  the  bladder,  OTIC  need  but  observe  the  violent, 
but  useless  straining  of  patients  affected  with  retention  of  urine,  from  pa- 
ralysis of  the  bladder*. 

The  urine  is  projected  along  the  urethra  with  the  greater  force,  as  it 
passes  from  a  spacious  cavity,  into  a  straight  canal,  and  it  is  expelled  with 
a  force  proportioned  to  that  of  the  muscular  coat  of  the  bladder:  we  know, 
that  in  old  men,  this  is  so  weak,  that  the  jet  of  urine  is  not  projected  more 
than  a  few  inches  beyond  the  urethra.  The  urethra  is  not  to  be  consider- 
ed as  inert  in  the  evacuation  of  the  urine,  it  closes  upon  it  and  acceler- 
ates its  flow,  aided  in  that  action,  by  the  bulbo-cavernous  muscles  to 
which  several  anatomists  have  given  a  name  taken  from  their  functions, 
(acceleratores  urinas.) 

The  action  of  these  muscles  expels  the  last  drops  of  urine  which  remain 
within  the  urethra,  when  the  bladder  is  completely  emptied.  The  con- 
tractile and  tonic  action  of  the  urethra  is  so  distinctly  marked,  that  its 
spasmodic  contraction  may  be  enumerated,  among  the  causes  which  fre- 
quently occasion  a  difficulty  in  introducing  the  catheter.  If  we  attempt 
to  inject  fluids  along  the  urethra  the  moment  we  remove  the  pipe  of  the 
syringe  which  closes  its  external  orifice,  that  instant,  theparietes  of  the 
canal  contract  on  the  fluid,  and  expel  it  with  a  rapid  jet. 

The  bladder  and  the  canal  of  the  urethra  are  lined  internally  with  a 
membrane,  whose  mucous  follicles  secrete  a  viscid  humour  calculated  to 
protect  the  parietes  of  these  organs,  against  the  action  of  the  urine,  and  to 
facilitate  the  evacuation  of  that  fluid.  This  membrane,  whose  surface  is 
more  extensive  than  the  cavities  which  it  lines,  forms  a  great  number  of 
folds,  which  disappear  when  the  bladder  is  distended  with  urine.  This 
mucus  is  secreted,  in  an  unusual  quantity,  in  catarahal  affections  of  the 
bladder,  and  becomes,  likewise,  more  ropy  and  more  albuminous.  The 
mucous  secretion  of  the  glands  of  the  urethrais  altered  in  its  quality,  and 
becomes  more  abundant,  from  the  action  of  the  venereal  poison,  and  gives 
rise  to  the  discharge  of  gonorrhaea;  the  orifices  of  these  lacunae  may 
stop  the  end  of  a  catheter,  so  as  to  add  to  the  difficulty  of  introducing 
that  instrumentf. 

*  It  is  scarcely  credible  that^some  physiologists  should  have  considered  this  organ  as 
inert  and  absolutely  passive,  in  the  evacuation  of  urine,  which,  in  their  opinion,  is  per- 
formed by  the  immediate  pressure  of  the  abdominal  muscles  and  diaphragm  on  that 
cavity.  Amid  this  variety  of  opinions,  if  you  wish  to  come  at  the  truth,  you  must  take 
a  medium.  Iliacos  intra  muros peccatur,  et  extrfi — Author's  Note. 

f  When  this  operation  is  performed  in  a  case  of  simple  paralysis  of  the  bladder,  it  is 
better  to  employ  a  very  large  catheter,  which  may  stretch  the  parietes  of  the  urethra, 
and  prevent  their  forming  into  wrinkles,  and  whose  rounded  beak  may  not  get  engaged 
in  the  lacunae  of  that  canal. 

When  in  a  case  of  retention  of  urine,  the  bladder  rises  above  the  pubis,  its  bas  fond 
is  .earned  upwards,  and  there  is  a  period  of  excessive  distension,  at  which,  like  the  ute- 
rus in  an  advanced  state  of  pregnancy,  it  seems  to  make  an  effort  to  rise  above  the  brim 


*  I       ;?^  IR 

The  urine  cannot  be  voided  at  the  same  time  as  the  faeces,  when  these? 
by  their  hardness,  compress  the  prostatic  and  the  membranous  part  of  the 
urethra,  situated  before  the  lower  extremity  of  the  rectum.  It  is  diffi- 
cult, and  often  impossible,  to  void  urine  during;  a  violent  erection,  as  the 
parietes  of  the  canal  are  then  closely  applied  to  each  other,  by  the  tur- 
gescence  of  the  corpus  spungiosum  and  of  the  corpora  cavernosa  of  the 
penis.  The  mode  of  sensibility  of  the  urethra,  is  besides  changed  in 
such  a  manner,  that  it  is  calculated  to  permit  only  the  emission  of  the 
seminal  fluid. 

When  the  bladder  is  completely  emptied,  it  sinks  behind  the  pubis ; 
the  tumour  which  it  formed  above  these  bones,  while  in  a  state  of  dis- 
tension, collapses,  the  abdomen  becomes  less  prominent,  respiration  more 
free,  and  there  is  a  general  feeling  of  lightness.  The  bladder  cannot  be 
completely  evacuated,  unless  the  pelvis  is  gently  inclined  forward ;  its 
has  fond)  which  is  on  a  lower  level  than  its  neck,  would,  in  any  other 
posture,  retain  a  certain  quantity  of  urine. 

XXXVI.  Of  the  physical  jiro/ierties  of  Urine.     As  this  fluid  varies  in 
quantity  in  a  healthy  man,  according  to  the  quantity  and  diuretic  quali- 
ties of  the  drink,  the  state  of  sleep  or  waking,  the  condition  of  the  se- 
cretions, arid  especially  of  the  perspiration,  it  is  very  difficult  to  deter- 
mine, accurately,  its  proportions.   Nothing  varies  more  than  its  quantity, 
as  may  be  ascertained,  by  comparing  the  different  calculations  on  that 
subject,  of  a  great  number  of  physiologists.     At  times,  the  urine  is  less 
in  quantity  than  the  drink  that  has  been  taken  in,  at  others,  more.     It 
may  be  affirmed,  however,  that  the  quantity  of  urine  voided  in  twenty- 
four  hours,  is  equal  to  that  of  the  insensible  perspiration  in  the  same  time, 
and  it  may,  therefore,  be  estimated  at  between  three  and  four  pounds,  in 
a  healthy  adult.     Its  colour  varies,  from  a  light  lemon  yellow,  to  an  or- 
ange, approaching  to  red.     Its  smell  and  flavour  are  peculiar,  and  dis- 
tinguish it  from  every  other  animal  fluid.    Its  colour  is,  in  general,  dark- 
er, its  smell  and  flavour  stronger  and  more  pungent,  as  it  is  less  in  quan- 
tity, as  the  circulatory  system  is  more  active  and  powerful,  and  as  the 
substances  of  our  food  are  more  animalized.    We  all  know  how  fetid  and 
how  scanty   is  the  urine  of  carnivorous  animals;  how  offensive  to  the 
smell  is  that  of  the  cat !    The  specific  gravity  of  urine  is  greater  than 
that  of  distilled  water,   and  varies,   according  to  the  quantity  of  saline 
and  other  substances,  which  it  holds  in  solution  :  it  is,  likewise,  slightly 
viscid,  but  not  ropy  like  the  serum  of  the  blood,  the  bile,  the  saliva,  and 
other  albuminous  fluids. 

XXXVII.  Of  the  chemical  properties  of  Urine*.     The  peculiar  qualities 
of  urine  are  always  more  marked  in  a  powerful  and  adult  male,  than  in 
children,  women,  and  weakly  persons.     By  chemical  analysis,  the  urine 
is  found  to  contain  eleven  substances,   dissolved  in  a  considerable  quan- 
tity of  water,  viz.  urea,  a  gelatinous  animal  master,  muriates  and  phos- 
phates of  soda  and  ammonia,  in  separate  or  in  triple  salts,  phosphate  of 
lime,  phosphate  of  magnesia,  phosphorus,  uric  and  benzoic  acids.     Be- 
sides these  substances  which  are  constantly  found  in  human  urine,  this 
fluid  may  contain  a  great  number  of  others;  and  if  it  be  true  that  the 

of  the  pelvis :  under  such  circumstances  in  women,  it  is  impossible  to  introduce  the 
catheter,  except  by  increasing  the  curve  of  the  instrument. — faithor's  Note. 

*  For  some  observations  on  the  physical  and  chemical  properties  of  urine,  see  AP- 
PENDIX, Note  P. 


tai 

vriiary  system  is  to  be  considered  as  the  emunctory  of  the  whole  econo- 
my, one  would  expect  to  find  in  it,  in  certain  proportions  and  under  dif- 
ferent circumstances,  the  whole  of  the  constituent  principles  which  ana- 
lysis has  hitherto  discovered  in  our  solids  and  liquids.  Hence,  douhtless, 
the  difference  in  the  results  obtained  by  the  chemists  who  have  investi- 
gated the  nature  of  the  urine,  by  allowing  it  to  run  into  decomposition,  or 
by  applying  to  it  various  re-agents. 

As  the  urine  is,  of  all  our  fluids,  that  which  has  the  greatest  tendency 
to  putrefaction,  it  should  be  examined  shortly  after  being  voided;  it  is 
then  distinctly  acid,  but  in  a  very  short  time,  and  especially  if  the  heat  of 
the  atmosphere  promotes  and  accelerates  these  changes,  it  becomes  tur- 
bid, its  component  parts  separate  and  form  various  precipitates.  Urea 
and  gelatine,  which  alone  of  its  constituent  principles  are  capable  offer- 
mentation  and  decomposition,  give  out  ammonia,  acetous  and  carbonic 
acids,  and  from  the  chemical  attraction  between  these  newly  formed  sub- 
stances, and  from  the  primitive  elements,  there  are  produced  new  com- 
pounds, the  knowledge  of  which  is  of  the  department  of  chemistry. 

Of  all  the  constituent  parts  of  urine,  the  most  essential  is  a  substance 
of  the  consistence  of  syrup,  deliquescent,  susceptible  of  crystallization, 
to  which  M.  Fourcroy  has  given  the  name  of  urea.  This  substance  to 
which  the  urine  owes  its  characteristic  properties,  its  peculiar  colour, 
smell,  and  flavour,  which  was  imperfectly  known  to  several  chemists  who 
had  sketched  some  of  its  features,  giving  it  different  names,  according  to 
the  notions  they  entertained  of  its  nature,  was  never  well  understood  till 
the  late  investigations  of  this  celebrated  professor*.  It  is  a  compound 
in  which  azote  prevails,  as  is  shown  by  the  immense  quantity  of  carbo- 
nate of  ammonia,  which  it  gives  out  in  distillation;  it  may  be  considered 
as  the  most  animalized  product,  having  such  a  tendency  to  the  putrid 
fermentation,  that,  even  while  in  the  animal  economy,  it  is  liable  to 
that  decomposition,  and  might  overcome  the  antiseptic  influence  of  the 
vital  power,  if  nature  did  not  get  rid  of  it  by  the  evacuation  of  the  urine. 

Sufficient  attention  has  not  hitherto  been  paid  to  the  symptoms  of  uri- 
nary fever,  an  affection  occasioned  by  the  protracted  retention  of  the 
urine  within  the  bladder.  I  have  observed,  on  several  occasions,  that 
no  kind  of  fever  is  attended  with  more  marked  signs  of  what  physicians 
term  putridity.  The  urinous  and  ammoniacal  smell  exhaled  from  the 
body  of  the  patients,  the  yellowish  and  oily  moisture  of  their  skin,  the 
parching  thirst  with  which  they  are  tormented,  the  dryness  and  redness 
of  their  tongue  and  throat,  their  frequent  and  irritable  pulse,  combined 
with  a  flaccid  and  doughy  feel  of  the  cellular  tissue,  every  thing  indicates 
that  the  animal  frame  is  threatened  with  the  most  speedy  and  dangerous 
decomposition. 

I  observed  similar  appearances  in  a  cat  and  in  a  rabbit,  in  which  I 
tied  the  ureters.  Nothing  is  easier  than  to  find  the  ureters,  and  to  per- 
form this  experiment.  After  a  crucial  incision  of  the  parit  tes  of  the 
abdomen,  on  the  left  side,  the  intestines  are  pushed  aside  to  the  left,  so 
-as  to  apply  a  ligature  on  the  right  ureter,  they  are  then  pushed  to  the 
right,  while  the  left  ureter  is  tied.  Both  ureters  are  seen  through  the 
peritoneum,  situated  behind  that  membrane,  in  the  lumber  region.  When 
the  ligatures  have  been  applied  to  the  ureters  about  their  middle,  the  di- 


*  See  his  work  entillcd.   System*  des  Connoissances   CJu^ques.  8vo.  torn,  X.  page 
753. 

Q 


122 

vided  edges  of  the  abdomen  are  brought  together  and  united  by  sutures, 
and  the  body  of  the  animal  is  wrapped  round  with  a  cloak  soaked  in  some 
emollient  decoction.  At  the  end  of  six  and  thirty  hours,  the  animals  be- 
came exceedingly  thirsty  and  restless,  their  eyes  glistening;  their  saliva, 
which  flowed  copiously,  exhaled  a  smell  evidently  urinous:  on  the  third 
day,  the  cat  was  seized  with  vomiting  of  a  slimy  substance,  remarkable 
by  its  having  the  same  smell.  This  convulsive  agitation  was  followed  by 
an  excessive  prostration  of  strength;  it  died  on  the  fifth  day;  the  intes- 
tines were  not  inflamed,  the  bladder  quite  empty,  the  ureters  distended 
with  urine  between  the  ligatures  and  the  kidneys,  and  as  large  as  the  ring 
finger.  The  kidneys  themselves,  gorged  with  urine,  were  turgid,  soften- 
ed, arid  as  if  macerated.  All  the  organs,  all  the  fluids,  the  blood  itself, 
partook  of  this  urinous  diathesis  ;*putrefaction  came  on  immediately  after 
death,  and  at  the  end  of  a  few  days,  an  almost  complete  decomposition  of 
the  body  had  taken  place.  In  the  rabbit  the  symptoms  were  less  violent 
and  rapid  ;  it  did  not  die  till  the  seventh  day  ;  the  smell  of  its  whole  body, 
though  evidently  urinous,  was  less  offensive,  and  the  putrefaction  which 
succeeded  was  less  rapid. 

These  two  experiments  confirm,  in  the  first  instance,  what  some  au- 
thors have  said  of  the  absence  of  urine  in  the  bladder,  when  the  ureters 
have  been  tied,  an  undeniable  proof  that  these  are  the  only  channels 
which  convey  the  urine  into  the  bladder ;  they  likewise  concur  in  afford- 
ing the  most  convincing  proof,  that  the  kidneys  are  the  emunctories  by 
means  of  which  the  blood  clears  itself  of  that  part  of  it  which  is  ani- 
malized  in  excess;  finally,  they  prove,  that  the  retention  of  this  fluid  is 
the  more  dangerous  to  the  animal  economy,  as  the  urine  itself  is  more 
animalized. 

Has  nature  the  means  of  supplying  the  evacuation  of  urine  by  other 
excretions  ?  might  this  highly  recrementitious  fluid  be,  without  danger, 
evacuated  by  other  emunctories?  With  a  view  to  answer  this  interest- 
ing question,  the  kidneys  have  been  extirpated  in  dogs.  The  removal  of 
one  kidney,  did  not  prevent  the  secretion  from  being  carried  on;  in  every 
case  in  which  both  kidneys  were  removed  at  once,  the  animal  died  in  a 
few  days,  and  on  opening  the  body,  there  was  uniformly  found,  a  con- 
siderable quantity  of  bile  in  the  gall-bladder,  in  the  small  intestines,  and 
even  in  the  stomach,  as  if  the  urea  had  endeavoured  to  make  its  escape 
in  that  direction,  by  combining  with  the  bile.  These  experiments  were 
performed  at  the  Hopital  Saint  Louis,  in  the  course  of  the  year  1803. 

Urea,  combined  with  a  certain  quantity  of  oxygen,  appears  to  form  an 
acid  peculiar  to  human  urine,  and  which  is  the  substance  of  the  greater 
numbers  of  urinary  calculi.  It  resembles  urea,  in  this,  that  its  crystals, 
exposed  to  heat,  give  out  carbonate  of  ammonia  5  but  it  differs  essentially 
from  it,  by  its  ready  concrescibility.  It,  in  fact,  crystallizes,  every  time 
the  urine  grows  cold,  and  forms  the  greatest  part  of  the  urinary  sediment. 
This  acid,  so  weak  that  several  chemists  have  considered  it  to  be  a  mere 
oxide,  has  been  called  by  M.  M.  Fourcroy  and  Vanquelin,  the  uric  acid. 
Among  its  distinguishing  characters,  may  be  mentioned  its  being  insolu- 
ble in  cold  water;  it  is  so  fixed,  that  several  thousand  times  its  own 
weight  of  boiling  water  is  required  to  dissolve  it,  hence  it  may  be  easy  to 
account  for  h.s  so  frequently  giving  rise  to  urinary  calculi :  we  may,  in- 
deed, wonder  that  this  complaint  is  not  of  more  frequent  occurrence, 
since  a  slight  cooling  Of  the  urine  is  sufficient  to  cause  a  precipitation 
and  crystallization  of  the  urine.  Thus,  every  time  an  extraneous  sub- 


123 

stance  drops  into  the  bladder,  it  becomes  the  nucleus  of  a  calculus,  form- 
ed by  the  uric  acid  becoming  concrete  on  the  surface  of  this  body,  which 
is  of  a  colder  temperature.  Quadrupeds  are  less  frequently  affected  with 
urinary  calculi,  from  the  absence  of  the  uric  acid  in  their  urine,  and  be- 
cause carbonate  of  lime,  of  which,  in  those  animals,  such  concretions  are 
formed,  is  a  salt  decomposed  with  effervescence  by  the  weaker  acids,  and 
several  such  acids  are  found  in  the  urine. 

Phosphorus,  which  may  be  considered  as  the  result  of  a  high  degree 
of  animalization,  enters,  in  considerable  proportions,  into  human  urine. 
Besides  the  phosphoric  salts  which  it  contains,  there  is  always  found  a 
certain  quantity  of  disengaged  phosphoric  acid,  which  holds  in  solution 
the  calcareous  phosphate,  ami  {jives  to  the  urine  its  manifest  acidity,  when 
examined  fresh,  or  shortly  after  it  has  been  voided.  It  was  from  urine, 
that  phosphorus  was  first  obtained  by  those  who  originally  dUrovered  it, 
and  from  that  fluid,  it  has  long  been  procured  for  the  purposes  of  com- 
merce. But  it  is  seldom  obtained  from  urine,  since  the  discovery  of  the 
phosphoric  acid  in  the  earth  of  bones,  has  rendered  the  manufacture  of 
phosphorus  easier  and  less  expensive.  In  the  urine  of  frugivorous  mam- 
raiferous  animals,  phosphoric  salts  have  their  place  supplied  by  calcare- 
ous carbonate. 

Certain  substances  impregnate  the  urine  with  a  peculiar  odour.  It  is 
well  known  that  if  one  remain  a  few  minutes  in  a  room  newly  painted 
with  oil  of  turpentine,  the  urine,  for  some  time  afterwards  gives  out  a 
smell  of  violets;  asparagus  gives  to  the  urine- a  very  remarkable  fetor. 

XXXVIII.  Besides  the  accidental  varieties  observed  in  the  urine,  vari- 
eties which  cannot  be  determined,  since  the  urine  is  never  uniformly  tfce, 
same  in  its  composition,  and  does  not  contain  the  same  ingredients  in  the 
same  person,  at  different  times  of  the  day,  according  to  the  quantity  and 
quality  of  the  food  and  drink,  the  exercise  which  has  been  taken,  the  af- 
fections of  the  mind  which  have  been  experienced,  &c.;  it  constantly 
varies,  according  to  the  time  which  has  elapsed  since  a  meal,  the  age  of 
the  subject,  and  the  diseases  under  which  he  may  labour. 

Physiologists  have  for  a  long  while,  admitted  two  and  even  three  dif- 
ferent kinds  of  urine,  according  to  the  time  at  which  it  is  voided;  they 
are  distinguished  by  the  names  of  urine  of  the  drink,  urine  of  the  chyle, 
and  urine  of  the  blood.  The  first  is  a  limpid  and  nearly  colourless  fluid, 
•which  frequently  retains,  in  a  remarkable  manner,  the  qualities  of  the 
drink,  and  is  voided  shortly  after  drinking,  and  has  scarcely  one  of  the 
characters  of  perfect  urine.  The  urine  of  the  chyle  or  of  digestion, 
voided  two  or  three  hours  after  a  meal,  is  more  formed,  still  it  is  not  per- 
fect, and  does  not  contain  all  the  component  parts  of  this  fluid. 

Lastly,  the  urine  of  the  blood  which  is  voided  seven  or  eight  hours  after 
a  meal,  and  in  the  morning  after  the  night's-  rest,  contains,  in  an  eminent 
degree,  all  the  qualities  of  urine,  hence  it  is  that  which  chemists  prefer 
using  in  their  analysis.  The  imperfect  state  of  the  two  former  kinds  of 
urine,  would  prove  better  than  the  rapidity  of  their  secretion,  the  disputed 
existence  of  a  peculiar  communication  from  the  stomach  and  intestines 
into  the  bladder. 

The  urine  of  children  and  that  of  nurses  contains  very  little  phosphate 
of  lime  and  phosphoric  acid ;  it  is  only  after  the  process  of  ossification  is 
completed,  that  these  elements  abound  in  the  urine.  That  of  old  men, 
on  the  other  hand,  contains  a  considerable  quantity  of  these  substances  $ 
their  osseous  system  already  containing  phosphate  of  lime  in  excess,  and 


124 

incapable  of  receiving  more,  this  saline  substance  would  ossify  all  the  tis- 
sues, as  it  sometimes  does  that  of  the  arteries,  the  ligaments,  the  carti- 
lages and  membranes,  if  the  urine  did  not  carry  off  the  greater  part. 

In  the  rickets,  it  is  by  the  urine  that  the  phosphate,  of  lime  is  carried 
out  of  the  system,  and  the  absence  of  that  substance  is  the  cause  of  molli- 
ties  ossium  $  on  the  approach  of  fits  of  the  gout,  the  phosphoric  ingredi- 
ents of  the  urine  diminish,  and  seem  to  be  carried  to  the  joints,  to  pro- 
duce in  their  vicinity  arthritic  concretions. 

The  great  quantity  of  saline  and  crystallizable  elements  which  enter 
into  human  urine,  accounts  for  the  frequency  of  the  concretions  which 
form  in  that  fluid.  Urinary  calculi  were  long  considered  as  formed  of  a 
single  substance,  which  the  ancients  thought  analogous  to  the  earth  of 
the  bones,  and  which  Schf^1^  *<^K  for  uric  acid.  The  late  investigations 
of  M.  M-  Fowi  uroy  and  Vanquelin  have  shown,  that  the  component  parts 
of  urine  are  too  numerous  and  too  complex  to  produce  uniformly  calculi 
of  one  kind  :  that  urinary  concretions,  most  frequently  formed  from  uric 
acid,  contain  urate  of  ammonia,  phosphate  of  lime,  phosphate  of  ammo- 
nia and  magnesia,  oxalate  of  lime,  silex,  and  that  these  substances, singly, 
or  in  binary  and  ternary  combinations,  form  the  materials  of  nearly  six 
hundred  calculi  which  they  analysed.  Notwithstanding  the  extent  of 
these  researches,  there  is  reason  to  believe,  that  when  carried  further  by 
the  same  chemists,  they  will  be  attended  with  results  still  more  varied. 
For,  as  there  is  no  integral  molecule  in  the  body  which  may  not  be  voided 
with  the  urine,  and  be  found  in  the  urine,  so  it  is  conceivable,  that  under 
certain  circumstances,  which  it  is  impossible  to  assign  or  to  forsee,  every 
tjilng  in  the  human  body  that  is  capable  of  concretion,  might  supply  the 
materials  of  urinary  concretions. 

This  variety  of  elements  in  the  composition  of  urinary  calculi,  the  ab- 
sence of  signs,  by  which  to  ascertain  their  nature,  the  sensibility  of  the 
parietes  of  the  bladder  which  would  be  irritated  by  agents  capable  of  dis- 
solving the  concretions(  so  frequently  formed  in  its  cavity,  must  render  it 
very  difficult,  not  to  say  impossible,  to  discover  a  lithontriptic  which 
should  supersede  the  necessity  of  a  surgical  operation,  whose  difficulties 
and  danger  have  been  much  over-rated. 

XXXIX.  The  energy  of  the  urinary  system  in  the  inhabitants  of  tem- 
perate climates,  has  been  considered  as  the  cause  of  the  frequency  of  cal- 
culous  affections  in  Holland,  England,  and  France,  while  they  are  very 
rare  in  more  southern  countries,  in  which  the  cutaneous  perspiration 
seems  to  be  substituted,  in  great  measure,  fyr  the  urinary  secretion. 
There  is  no  part  of  the  world  in  which  cases  of  stone  in  the  bladder  are 
more  frequent  than  in  England, and  especially  i»  Holland,  in  which  a  cold 
und  damp  atmosphere  is  unfavourable  to  perspiration,  which  is,  at  any 
rate,  but  scanty  in  persons  of  a  leucophlegmatic  temperament  like  that  of 
the  Dutch.  In  no  other  country,  could  a  lithotnist  (Raw)  have  operated 
on  more  than  fifteen  hundred  patients,  it  is  said,  successfully.  Diabetes, 
or  an  immoderate  discharge  of  urine,  a  disease  ivhich  appears  to  depend 
on  an  excessive  relaxation  of  the  renal  tissue,  js  of  frequent  occurrence 
only  in  cold  and  damp  countries,  as  Holland,  England,  and  Scotland;  it  is 
more  rare  in  France  and  Germany,  and  is  unknown  in  warm  climates. 
This  relaxation  of  the  renal  tissue  in  diabetes,  depends  on  the  exhaustion 
of  the  urinary  organs  called  into  too  frequent  action,  as  is  proved  by  the 
efficacy  of  tonics  and  astringents  in  the  treatment  of  that  complaint. 

Cutaneous  affections,  on  the  contrary,  seem  to  belong  to  the  inhabitants 


125 

of  southern  countries*.  Lepra  originated  in  Judea;  the  elephantiasis 
rubra  of  Cayenne,  the  framboesia  of  Java,  the  yaws,  elephantiasis,  her- 
petic  and  psoric  eruptions,  are  more  frequent  among  the  inhabitants  of 
southern  latitudes  than  among  those  who  live  under  the  temperate  zones. 
In  countries  near  to  the  equator,  the  surface  of  the  body,  habitually  ex- 
posed to  an  ardent  atmosphere,  is  powerfully  excited  :  the  skin  is  irrita- 
ted, and  its  secretion  increased;  perspiration  becomes  so  profuse,  thatit 
weakens,  in  a  short  time,  those  who,  coming  from  distant  countries,  are 
not  accustomed  to  so  intense  a  heat.  The  activity  of  the  cutaneous  sys- 
tem exceeds  that  of  the  urinary  system,  whose  action  decreases  in  propor- 
tion. These  differences  in  the  energy  of  the  two  systems,  account  readily 
for  the  difference  of  their  diseases:  for,  it  is  a  law  of  Nature,  that  the 
more  an  organ,  or  system  of  organs,  is  called  into  action,  the  more  it  is 
liable  to  disease,  which  is  but  a  derangement  of  its  action. 

Calculous  affections  are  more  frequent  in  children  and  old  people  than 
in  adults.  In  old  age,  the  proportionate  quantity  of  the  urine  exceeds 
that  of  the  perspiration.  Phosphoric  salts,  the  base  of  a  great  number 
of  urinany  calculi,  are  more  abundant  in  old  men,  as  is  proved  in  them  by 
the  ossification  of  the  arteries,  of  the  ligaments,  of  the  cartilages,  of  the 
membranes,  ihe  solidification,  ar.d  the  almost  universal  induration  of  the 
different  parts.  In  children  the  activity  of  the  urinary  system  is  propor- 
tionate to  that  of  the  digestive  organs.  Destined  to  throw  out  the  resi- 
due of  nutrition,  which,  at  that  period,  is  very  active,  the  organs  by 
which  the  urine  is  secreted  are  likewise  endowed  with  considerable  ener- 
gy. Lastly,  it  is  observed,  that  the  greatest  number  of  calculous  patients 
received  into  the  hospitals  of  large  towns,  come  from  low  and  damp 
streets  near  to  rivers;  every  thing-,  therefoie,  tends  evidently  to  esta- 
blish, that  the  frequency  of  urinary  calculi,  depends  on  an  increase  of 
activity,  in  the  organs  destined  to  the  secretion  and  excretion  of  urine. 


CHAPTER    II. 


OF  ABSORPTION. 

XL.  IN  the  history  of  the  phenomena  of  life,  a  statement  of  the  func- 
tions of  the  absorbent  system,  ought  immediately  to  follow  that  of  the 
functions  of  the  digestive  organs.  The  vessels,  which  take  up  the  chyle 
separated  from  the  food,  by  the  action  of  the  organs  of  digestion,  form  a 
considerable  part  of  the  absorbent  system,  bear  a  perfect  resemblance  to 
the  other  lymphatics,  and  differ  from  them  only  in  their  origin.  When 
digestion  is  not  going  on,  those  vessels  convey  lymph  absorbed  in  the  in- 
testinal canal,  the  inner  part  of  which,  even  when  in  a  state  of  emptiness, 
is  always  bedewed  by  an  abundant  quantity  of  serous  mucus. 


*  It  would  be  more  correct  to  say  that  cutaneous  affections  are  more  frequent  among 
the  inhabitants  of  southern  climates. 


126 

.  There  exists  in  all  the  parts  of  the  human  body,  in  the  interior,  as  well 
as  on  the  surface  of  our  organs,  vessels  whose  office  it  is  to  absorb,  and 
to  carry  into  the  mass  of  the  blood,  those  substances  by  which  our  ma- 
chine is  maintained  and  kept  in  repair,  as  well  as  what  comes  off  in  the 
continual  destruction  of  our  parts;  for,  it  must  not  be  forgotten,  that  the 
organized  and  living  machine,  inwardly  acted  upon  by  a  double  impulse, 
is  perpetually  undergoing  decay  and  renovation. 

XLI.  Absorption  is  effected  on  substances  introduced  from  without ; 
such  is  the  absorption  from  the  skin,  and  the  absorption  of  the  chyle, 
&c.  At  other  times,  absorption  takes  place  in  fluids  effused  by  arterial 
transudation  ;  such  is  the  serosity  which  moistens  the  serous  membranes, 
the  fat,  the  marrow  of  the  bones,  and  this  absorption,  almost  always, 
bears  a  proportion  to  transudation,  so  that  the  serosity,  absorbed  as  fast 
as  it  is  effused  on  the  surface  of  the  membranes  which  lie  in  close  con- 
tact, except  in  cases  of  dropsy,  never  accumulates  so  as  to  separate 
those  membranes.  Finally,  there  is  a  kind  of  absorption,  which  may  be 
termed  nutritive  or  molecular,  because  it  exerts  its  influence  on  mole- 
cules, which,  in  the  process  of  nutrition,  are  separated  from  the  organs, 
and  replaced  by  others.  It  is  this  absorption  which  brings  about  the  de- 
composition of  organs,  and  to  which  John  Hunter  gave  the  name  of  in- 
terstitial absorption.  By  means  of  it,  the  thymus,  so  voluminous  in  the 
foetus,  disappears  entirely  in  the  adult.  This  absorption  seems  to  be  in- 
cessantly going  on,  and  to  carry  on  decomposition,  with  a  force  that  can- 
not be  resisted.  It  explains  in  a  satisfactory  manner,  the  spontaneous 
erosions  of  the  living  solids,  of  which  ulceration*  is  the  consequence. 
M.  Dumas  has  endeavoured  to  explain  in  this  way,  the  sensation  of  hun- 
ger, which,  in  the  opinion  of  that  physician,  is  felt  when  the  absorbents 
exert  on  the  solid  coats  of  the  stomach,  their  activity  previously  employ- 
ed in  taking  up  liquids.  But  to  give  even  a  degree  of  probability  to  that 
supposition  which  is  entirely  gratuitous,  it  would  be  necessary  to  show, 
that  the  parietes  of  the  stomach  have  been  found  destroyed  or  thinned,  in 
persons  who  have  died  of  hunger.  The  parietes  of  the  stomach  of  such 
perspns,  have,  on  the  contrary,  been  found  thickened  and  in  a  state  of 
contraction.  This  inward  absorption  is  promoted  by  inflammation,  hence 
the  advantage  of  applying  heat  to  indolent  tumours,  and  of  exciting  a 
slight  inflammation  in  swollen  glands,  in  order  to  bring  about  resolution. 
It  is  on  that  account,  that  in  swelling  and  induration  of  the  testicle,  unat- 
tended by  cancer  of  the  part,  the  operation  for  hydrocele  by  injection, 
may  be  safely  employed. — Of  this  I  had  a  convincing  proof,  a  few  years 
ago;  a  gardener,  born  deaf  and  dumb,  had  for  some  years  an  hydro- 
cele, which  he  was  in  the  habit  of  getting  tapped  every  six  months. 
When  I  last  tapped  it,  I  found  the  testicles  swollen  and  hard,  and  three 
times  larger  than  in  its  natural  state ;  the  patient,  however,  was  free 
from  pain.  A  considerable  quantity  of  a  reddish  serous  fluid  was  dis- 
charged; at  the  end  of  two  days,  inflammation  of  the  tunica  vaginalis 
came  on,  the  scrotum  became  enlarged,  and  was  covered  with  emollient, 
poultices.  At  the  end  of  twenty  days,  the  testicle  was  a  good  deal  lessen- 
ed in  size,  and  adhered  to  the  inside  of  the  tunica  vaginalis :  the  cure 
was  considered  radical,  and  proved  such;  for,  though  it  is  now  ten  years 
since  the  operation  was  performed,  the  water  has  not  collected,  and  the 
patient  continues  in  the  laborious  employment  of  his  business.  I  frequent- 

*  NosograpUe  Chirurgicale  tome  1.  art.  Ulceres  ^tomques. 


127 

ly  meet  him,  and  he  never  fails,  by  inarticulate  sounds  and  signs  of  satis- 
faction, to  express  to  me  his  gratitude. 

The  processof  absorption  is  very  active  in  children,  in  women,  during 
sleep,  in  the  morning,  when  the  body  is  refreshed  by  the  night's  rest.  Is 
a  state  of  weakness  favourable  or  unfavourable  to  that  process  ?  it  is  well 
known,  that  there  are  robust  men  who  have  intercourse  with  women  in- 
fected with  the  venereal  virus,  and  who  escape  the  contagion,  unless  they 
expose  themselves  to  it,  when  debilitated  by  excesses.  A  mind  free  of 
fear  and  anxiety,  has  ever  been  considered  in  the  Eastern  countries,  a 
safe-guard  against  the  plague.  A  dog,  caeteris  paribus,  is  in  much  less 
danger  from  the  bite  of  a  viper,  when  suddenly  bitten,  than  when  he  has 
been  sometimes  gazing  at  the  reptile,  and,  more  or  less  terrified  by  the 
sight.  But  in  all  these  cases,  does  debility  favour  the  introduction  of  the 
contagious  matter,  by  increasing  theforce  of  absorption;  or  is  it  not  more 
probable,  that  by  affecting  the  nervous  system,  it  renders  it  more  suscep- 
tible of  deleterious  impressions*  ? 

XLIL  Absorption  is  much  less  active,  on  the  external  surface  of  the 
body,  than  on  the  surface  of  its  internal  cavities,  and  in  the  very  substance 
of  our  organs.  Cutaneous  absorption,  under  certain  circumstances,  has 
even  so  little  activity,  as  to  have  led  some  physiologists  to  doubt  its  exist- 
ence. The  absorbing  orifices  of  vessels  which  arise  on  the  surface  of 
the  body,  are  covered  by  the  epidermis.  This  covering,  which  is  insen- 
sible, and,  as  it  were,  inorganic,  forms  a  sort  of  separation  between  the 
external  and  internal  part  of  our  being,  and  opposes,  or  renders  more  dif- 
ficult, the  absorption  of  substances  in  immediate  contact  with  our  body, 
and  if  it  be  considered,  that  we  are  frequently  immersed  in  the  midst  of 
gases  and  other  substances,  to  a  certain  degree,  deleterious,  it  will  be  un- 
derstood, hov/  essential  it  was,  that  the  absorbing  surface  of  the  skin, 
should  not  be  entirely  exposed,  and  that  cutaneous  absorption  should  not 
be  easily  carried  on. 

The  increased  weight  of  the  body,  after  exercise  in  wet  weather;  the 
abundant  secretion  of  urine,  after  remaining  long  in  the  bath;  the  mani- 
fest enlargement  of  the  glands  of  the  groin,  after  keeping  the  feet  im- 
mersed for  a  considerable  time^in  water,  an  experiment  often  performed 
by  Mascagni  on  himself  t;  the  effects  pf  mercurial  frictions,  Sec.  show, 

*  The  latter  is  undoubtedly  the  explanation. 

f  It  is  now  more  than  twenty  years  since  the  subject  of  cuticular  absorption  first  en- 
gaged the  attention  of  the  medical  men  of  Philadelphia,  during1  which  time,  it  has  been 
prosecuted  with  an  ardour  and  success  hig-hly  honourable  to  those  concerned- in  the  in- 
quiry. As  early  as  the  year  1800,  it  was  shown,  or  at  least  rendered  highly  probable 
by  Dr.  Rousseau,  that  the  pulmonary  organs,  and  not  the  skin,  constitute  the  avenue 
through  which  certain  substances  enter  the  system.  By  cutting;  oft' all  communication 
with  the  lungs,  which  he  easily  effected  by  breathing  through  a  tube  protruded  into  the 
external  atmosphere,  lie  ibund  that  though  the  surface  of  his  body  were  bathed  with 
the  juice  of  garlic  or  the  spirits  of  turpentine,  none  of  the  qualities  of  these  fluids  could 
be  detected,  either  in  the  urine,  or  serum  of  the  blood.  Conducted  nearly  on  the  same 
principle,  but  with  a  greater  diversity  of  substances,  experiments  exceedingly  well  de- 
vised and  ably  executed,  have  since  been  made,  by  persons  of  opposite  prepossessions, 
to  an  almost  incredible  extent.  Contradictory  as  many  of  these  are,  a  candid  examina- 
tion of  the  whole  will  still  lead  to  a  pretty  satisfactory  conviction,  that  absorption  from 
the  surface  of  the  human  body  does  not  exist  as  a  natural  and  ordinary  function. 

Borne  down  by  the  weight  of  evidence  against  them,  most  of  the"  advocates  of  the 
ancient  hypothesis  were  indeed  prepared  to  abandon  it,  as  no  longer  tenable,  when 
about  two  years  n£o  an  experiment  made  by  Dr.  Massy,  again  revived  their  faith  in  cuti- 
cular absorption.  This  experimentalist  very  clearly  proved  that  if  the  body  be  immer?- 


128 

however,  in  an  unquestionable  manner,  that  absorption  takes  place  through 
the  skin,  with  more  or  less  rapidity,  according  to  circumstances.  It  must 
be  taken  into  account,  that  the  means  which  promote  cutaneous  absorp- 
tion, operate,  at  least  as  much, by  altering  the  structure  of  the  epidermis, 
as  by  increasing  the  action  of  the  absorbing  orifices.  In  this  manner 
the  bath  appears  to  operate,  by  softening  the 'texture  of  the  epidermis  : 
and  frictions,  by  displacing  and  raising  its  scales. 

It  is  by  means  of  frictions,  that  we  succeed  in  introducing  into  the  lym- 
phatic system,  medicines  possessing  purgative,  febrifuge,  sedative,  or 
diuretic  qualities,  combined  with  the  gastric  juice,  or  diluted  in  any  other 
liquids,  for,  as  has  been  shown  by  the  experiments  performed  at  the  Sal- 
petriere,  by.M.  M.  Dumeril  and  Alibert,  in  the  name  of  the  Philomatic 
Society,  the  mixture  with  saliva  or  gastric  juice,  of  the  medicines  which 
are  to  be  administered  by  friction,  is  not  necessary  to  insure  their  absorp- 
tion. Extract  of  opium  has  soothed  pain,  bark  has  checked  fits  of  inter- 
mittent fever,  rhubarb  has  procured  alvine  evacuations  :  squills  have 
stimulated  powerfully  the  action  of  the  urinary  organs,  nor  has  the  pre- 
vious mixture,  with  gastric  juice,  of  these  substances  reduced  into  pow- 
der, seemed  to  increase  or  diminish  their  efficacy. 

Absorption  takes  place  quickly  and  readily,  wherever  the  epidermis  is 
thin,  habitually  moist,  and  the  skin  delicate,  so  as  to  leave  almost  bare  of 
covering,  the  subjacent  parts,  as  on  the  lips,  in  the  inside  of  the  mouth, 

ed  in  a  decoction  of  madder,  the  colouring1  matter  of  this  substance  will  be  taken  in,  and 
may  be  displayed  in  the  urine,  by  using  any  one  of  the  alkalies  as  a  test. 

Determined,  if  possible,  to  put  this  long1  agitated  question  to  rest,  Dr.  Rousseau,  as- 
sisted by  his  friend,  Dr.  Samuel  B.  Smith,  has  subsequently  performed  a  series  of  ex- 
periments, many  of  which  we  witnessed,  with  every  variety  of  substance,  mild  and  acrid, 
volatile  and  fixed,  nutritive,  medicinal,  and  poisonous. 

The  result  of  these  extensive  researches  is  : 

1.  That  of  all  the  substances  employed,  madder  and  rhubarb  are  those  only  which 
affect  the  urine      The  latter,  of  the  two,  the  more  readily  enters  the  system.     Neither 
of  these  substances  can  be  traced  in  any  other  of  the  secretions,  or  excretions,  or  in  the 
serum  of  the  blood. 

2.  That  the  power  of  absorption  is  limited  to  a  very  small  portion  of  the  surface  of 
the  body.     The  only  parts  indeed  which  seem  to  possess  it,  are  the  spaces  between 
the  middle  of  the  thigh  and  hip,  and  between  the  middle  of  the  arm  and  shoulder.    To- 
pical bathing1  with  a  decoction  of  rhubarb  or  madder,  or  poultices  of  these  substances 
applied  to  the  back,  or  abdomen,  or  sides,  or  shoulders,  producing-  no  change  in  the 
urine,  &c.    Equally  ineffectual  was  the  immersion  of  the  feet  and  hands  in  a  bath  of  the 
same  materials.     After  being1  kept  in  it  several  hours,  not  the  slightest  absorption  was 
afforded. 

Such  is  the  state  in  which  this  interesting-  subject  is  at  present  left.  Though,  per- 
haps, n<it  absolutely  decided,  enough  surely  has  been  done  to  demonstrate  that  cuticu- 
lar  absorption  rarely  happens,  and  whenever  it  does,  it  cannot  be  deemed  the  effort  of 
a  natural  function.  Covered,  as  is  the  whole  surface  of  the  body  by  the  impervious 
cuticule,  it  is  manifest  to  us  that  absorption  can  only  take  place  in  one  of  two  ways, 
either  by  forcing  the  substance  under  the  scales  of  the  epidermis,  as  in  the  instance  of 
the  application  of  frictions,  or  by  long"  continued  bathing1,  the  cuticle  becomes  so  chang- 
ed in  its  organization,  as  to  admit  of  transudation,  or  the  insinuation  of  the  fluid  under 
its  squamous  structure,  so  as  to  come  in  contact  with  the  mouths  of  the  lymphatics  situ- 
ated within. 

At  all  events,  whatever  difference  of  opinion  may  be  entertained  as  to  the  degree  of 
conclusiveness  of  the  experiments  to  which  I  have  alluded,  it  can  hardly  be  thought  ne- 
cessary to  resort  to  cuticular  absorption,  to  explain  the  facts  enumerated  by  our  author 
as  proofs  of  the  existence  of  the  function.  These,  and,  perhaps,  all  other  phenomena, 
hitherto  referred  to  the  agency  of  absorption  by  the  skin,  may  be  more  rationally  ac- 
counted for  on  the  principle  of  pulmonary  absorption,  and  the  b>v  of  sympathy. — 
Chapman. 


129 

on  the  surface  of  the  glands,  Sec.  The  complete  removal  of  the  epider- 
mis, favours  absorption  from  all  parts  of  the  skin  which  it  covered. 
Hence  the  least  scratch  on  the  fingers  of  an  accoucheur  touching  women 
infected  with  the  venereal  virus,  exposes  him  to  this  peculiar  infection, 
which,  in  such  cases,  is  the  more  to  be  dreaded,  from  the  admission  of 
the  virus  by  an  unusual  course.  The  innoculation  of  variolous  and  vac- 
cine matter,  equally  furnishes  proofs  of  the  obstacle  which  the  epidermis 
presents  to  cutaneous  absorption,  and  of  the  facility  with  which  that  func- 
tion takes  place,  from  surfaces  denuded  of  that  covering.  Absorption 
goes  on,  likewise,  with  great  activity,  from  the  surfaces  of  internal  parts, 
but  it  no  where  is  so  considerable,  as  in  the  intestinal  canal,  and  it  would 
perhaps  be  the  most  favourable  part  for  introducing  medicinal  substances 
into  the  animal  economy,  if  when  swallowed,  they  did  not  undergo  changes, 
by  mixing  with  the  gastric  juices,  or  with  the  intestinal  fluids  and  faecal 
substances,  when  injected  by  the  ?ectum.  From  the  evacuation  by  urine 
of  clysters  of  warm  water,  soon  after  they  have  been  administered,  it  is  to 
be  presumed,  that  the  great  intestines  absorb,  almost  as  powerfully  as  the 
rest  of  the  digestive  canal.  A  pint  of  warm  water  injected  into  the  abdo- 
men of  a  large  dog  or  sheep,  is  often  absorbed  in  less  than  an  hour,  and 
the  effusions  which  take  place  in  those  cavities,  would  possibly  not  re- 
quire an  operation  to  let  them  out,  if  such  fluids  were  not  subject  to  coa- 
gulation, and  if  the  absorbing  surfaces  were  not  diseased. 

Besides  absorption  from  surfaces,  there  exists,  as  we  have  already  stated, 
another  which  takes  place  in  the  living  solid,  and  in  the  internal  substance 
of  the  organs.  It  is  by  this  kind  of  absorption,  that  the  nutritive  decom- 
position is  effected ;  by  means  of  it,  the  living  matter  is  incessantly  reno- 
vated. Its  vitiated  action  accounts  for  the  spontaneous  formation  of 
ulcers,  the  disappearing  of  the  thymus,  the  atrophy  of  parts  in  which  nu- 
trition is  carried  on,  in  a  sluggish  manner ;  the  resolution  of  certain 
tumours,  and  many  other  phenomena,  are  dependent  on  the  same  cause. 
I  do  not  think,  however,  that  it  is  possible  to  admit  the  explanation  of  the 
sensation  of  hunger,  adopted  by  Professor  Dumas,  who  believes  that  it 
depends  on  the  action  of  the  absorbing  orifices  directed  against  the  or- 
ganized substance  of  the  stomach,  in  the  absence  of  aliment  on  which  to 
act*.  The  sensation  of  hunger  is  felt  only  in  the  stomach,  although  its 
effects  extend  to  all  parts  of  the  body:  it  begins  in  a  circumscribed  spot, 
its  seat  is  limited,  yet  absorption  takes  place  every  where,  so  that  if  the 
hypothesis  in  question  had  any  foundation,  the  sensation  of  hunger  ought 
to  be  felt  at  the  heel,  as  well  as  at  the  pit  of  the  stomachf. 


*  Both  hunger  and  thirst  seem  to  be  sensations,  excited  by  the  stomach's  sympathis- 
ing with  the  general  exhaustion  of  the  system,  and  are  the  means  employed  by  nature 
to  admonish  us  of  the  necessity  of  repairing  the  wastes  which  it  sustains  from  abstinence. 
An  office  so  imporsant  to  our  well  being,  and  even  existence,  is  not  left  to  reason, 
which  might  often  err,  but  is  put  under  the  care  of  an  instinct,  far  more  certain  in  its 
operation.  Besides  these  two  sensations,  the  stomach  has  others  equally  specific :  as 
satiety,  longing,  loathing,  sickness,  &c.  &c.— Chapman. 

f  It  does  not  fall  to  the  lot  of  every  one,  to  err  like  M.  Dumas,  whose  talents  and  in- 
genuity I  have  much  pleasure  in  acknowledging.  He  imagines  rickets  to  consist,  in 
a  deficient  influence  of  the  nervous  system  on  the  bones;  which  would  constitute  a 
kind  of  paralysis.  Anatomy  shows  the  presence  of  no  nerves  in  the  tissue  of  thebones> 
and  veins  and  arteries  are  alone  seen  to  enter  the  foramina,  and  no  nerves  appear 
to  be  transmitted  through  them.  The  functions  of  the  bones  made  it  unnecessary  that 


130 

The  radicles  from  which  the  lymphatics  arise,  have  orifices  so  very 
minute,  that  they  are  imperceptible  to  the  naked  eye;  a  tolerably  accu- 
rate notion  may  be  formed  of  them,  by  comparing  them  to  the  puncta  la- 
chrymalia,  which  are  larger  and  more  easily  discovered.  Each  orifice 
endowed  with  sensibility,  and  with  a  peculiar  power  of  contraction,  di- 
lates or  contracts,  absorbs  or  rejects,  according  as  it  is  affected  by  the 
substances  which  are  applied  to  it.  The  variations  of  the  absorbing  pow- 
er, according  to  the  age,  the  sex,  the  constitution,  and  different  periods 
of  the  day,  show  that  it  cannot  be  compared,  as  several  physiologists  have 
clone,  to  that  principle  which  makes  fluids  ascend,  contrary  to  the  laws 
of  gravitation,  in  capillary  tubes.  If  absorption  were  a  process  merely 
mechanical,  it  would,  in  no  case,  be  accelerated  or  retarded,  and  would 
proceed  with  a  regularity  never  observed  in  the  vital  functions.  The 
mouth  of  every  lymphatic,  when  about  to  absorb,  erects  itself,  draws 
towards  itself,  and  raises  the  surrounding  membranous  parts,  and  thus 
forms  a  small  tubercule  similar  to  the  puncta  lachrymalia.  These  little 
bulgings  deceived  Lieberkuhn,  and  led  him  to  think,  that  the  absorbents 
of  the  intestines,  originated  from  small  ampullalae,  or  vesicular  enlarge- 
ments, which,  as  so  many  exhausted  receivers,  pumped  up  the  fluid  ex- 
tracted from  the  food*.  This  physiologist  may,  further,  have  been  led 

they  should  be  endowed  with  that  peculiar  sensibility  which  requires  the  existence  of 
nerves.  The  bones  are  active  by  being  subject  to  the  process  of  nutrition,  but  in 
every  other  respect,  they  are  absolutely  passive.  In  the  opinion  of  some  people,  such 
doctrines  are  real  discoveries.  Credat  judxus  Jipella,^  non  ego. — Author's  Note. 

*  As  to  the  precise  manner  in  which  absorption  is  effected,  physiologists  are  not 
agreed.  By  some  it  is  contended,  that  it  is  entirely  the  result  of  capillary  attraction. 
To  the  exercise  of  this  species  of  affinity,  three  circumstances  seem  only  to  be  de- 
manded : 

1.  The  tube  must  not  exceed  a  certain  size. 

2.  It  must  be  of  an  equal  calibre  throughout. 

3.  One  of  its  extremities  must  be  immersed  in  a  fluid. 

Notwithstanding  what  has  been  urged  to  the  contrary,  capillary  attraction  unques- 
tionably is  influenced  neither  by  the  flexibility  of  the  tube,  nor  its  position.  It  is  now 
perfectly  well  ascertained,  that  the  operation  goes  on  whether  the  tube  be  soft  or  hard, 
or  whether  it  be  placed  vertically,  horizontally,  or  obliquely. 

These  facts  being  admitted,  and  also,  that  the  lymphatic  vessels  are  within  the  di- 
mensions necessary  to  capillary  attraction,  which  they  undoubtedly  are,  the  hypothesis 
referring  absorption  to  this  principle,  does  not,  at  first  view,  strike  us  as  altogether  un- 
reasonable. When  examined,  however,  more  clearly,  it  will  be  found  liable  to  all  the 
embarrassments  enumerated  in  the  text,  and  to  others  of  not  less  weight. 

Two  additional  objections  at  once  occur  to  us. 

1.  Did  the  absorbents  act  mechanically,  as  is  alleged,  they  would  take  up  indiscri- 
minately all  fluids  presented  to  their  mouths,  instead  of  which,  they  exercise  a  degree 
of  selection  amounting  almost  to  fastidiousness. 

2.  The  absorbents  have  not  that  mechanism  which  capillary  attraction  requires. 
They  frequently  swell  or  bulge  out  in  their  course,  and  become  of  irregular  capaci- 
ties.    Even  at  their  orifices  they  assume  the  figure  of  the  funnel,  commencing  with  an 
exceedingly  minute  opening,  which  suddenly  expands.     Aware  of  the  unfavourable- 
ness  of  the  structure  to  the  progression  of  fluids,  it  has  been  maintained  by  some  other 
of  the  advocates  of  capillary  attraction,  that  the  fluid  is  simply  imbibed  by  the  power  of 
this  principle,  and  afterwards  propelled  by  the  united  force  of  muscular  pressure,  and 
the  action  of  the  contiguous  arteries. 

We  do  not  think  the  hypothesis  at  all  improved  by  this  modification  of  it.  We  be- 
lieve, that  in  absorption  there  is  no  capillary  influence,  or,  indeed,  any  sort  of  extrinsic 
agency  employed.  It  seems  to  us  to  be  owing  altogether  to  the  inherent  contractile 
power  of  the  vessel,  and  bears  no  very  remote  analogy  to  the  peristaltic  action  of  the 
intestines.  We  will,  however,  in  a  few  words,  explain  our  meaning  more  distinctly. 

When  chyle,  or  any  appropriate  fluid,  is  applied  to  the  mouth  of  an  absorbent,  it  is 


131 

into  error,  by  the  nervous  papillae  of  the  inner  membrane  of  the  canal, 
swollen  by  the  determination  of  blood  attending  irritation,  the  natural 
consequence  of  the  friction  of  the  alimentary  substances.  The  inhaling 
faculty  belongs,  not  only  to  the  orifices  at  the  extremity  of  each  radicle, 
but,  likewise,  to  the  lateral  pores,  which  are  infinitely  numerous,  in  the 
parietes  of  the  vessels*. 

XLIII.  After  arising  on  the  surface,  and  in  the  interior  of  the  body, 
by  radicles  in  close  contact,  the  lympathetics  creep  and  coil  themselves, 
describe  numerous  curves,  unite,  then  divide,  and  presently  unite  again, 
and  from  these  numerous  inosculations,  there  results  a  net-work,  with 
close  meshes,  forming,  with  that  of  the  blood-vessels,  the  texture  of  the 
cellular  tissue  and  of  the  membranes. 

Each  lamina  of  cellular  tissue  is,  in  the  opinion  of  Mascagni,  nothing 
but  a  mesh- work  of  lymphatics — the  texture^of  the  membranous  and 
transparent  tissues,  as  the  pleura  and  the  peritoneum,  resembles  that  of 
the  lamina  of  the  cellular  tissue;  in  fine,  the  same  vessels  form  the  ba- 
sis of  the  mucous  membranes  which  line  the  internal  parts  of  the  alimen- 
tary canal  of  the  trachea  and  urethra.  The  Italian  anatomist  succeeded 
in  filling,  with  quicksilver,  all  the  tissues  which  he  considered  as  lympha- 
tic 5  but  Ruysch,  in  his  admirable  injections,  reduced  all  the  membranes, 
and  the  lamina  of  the  adipose  tissue,  into  a  net-work  purely  arterial,  of 
which  the  meshes  were  so  very  closely  united,  as  to  leave  spaces  that 
could  scarcely  be  perceived  by  the  microscope,  and  from  his  preparations 
he  inferred,  the  arterial  capillary  vessels,  singularly  divided  and  convo- 
luted, form  the  basis  of  cellular  and  membranous  tissues.  To  satisfy 
one's  self,  that  neither  the  pleura  nor  the  peritoneum  are  formed  as  Mas- 
cagni or  Ruysch  imagined,  one  need  only  consider,  that  arterial  exhalation 
and  lymphatic  absorption  take  place,  from  the  whole  extent  of  internal 
surfaces,  and  that  these  two  functions  prove  the  existence  of  both  arte- 
ries and  absorbents,  in  those  membranes,  and  in  the  cellular  tissue.  The 
prejudices  of  those  two  anatomists,  so  celebrated,  the  one  by  his  study 
of  the  absorbents,  and  the  other  by  his  beautiful  injections  of  the  most 
minute  arteries,  are  to  be  attributed  to  the  importance  which  we  are 
pleased  to  assign  to  the  objects  which  particularly  engage  our  attention, 
and  likewise  to  the  distension  of  the  minute  vessels  by  the  injection : 
these  being  distended  beyond  their  natural  state,  compress  and  conceal 
the  neighbouring  parts. 

The  lymphatics,  after  emerging  from  among  the  cellular  substance, 
unite  into  trunks  sufficiently  large  to  be  distinguished  from  the  lamina  of 
that  tissue.  These  trunks  proceed  towards  certain  parts  of  the  body, 
there  they  become  united  to  other  trunks,  follow  a  parallel  course,  and 
frequently  communicate  together.  The  lymphatics  are  not  single  in  their 
course,  as  the  arteries  and  veins;  they  collect  together,  form  fasciculi  of 
different  sizes,  some  of  which  are  deep  seated  and  accompany  the  blood- 
vessels, while  others  of  them  are  more  superficial,  corresponding  to  the 
subcutaneous  veins  of  the  limbs,  and,  like  them,  lying  between  the  skin 
and  the  aponeuroses,  and  in  greatest  number,  on  the  inner  side  of  the 


excited  by  the  stimulus  of  the  fluid  to  an  erection  ofits  orifice,  in  consequence  of  which 
the  latter  is  rendered  pervious.     The  fluid  being  now  introduced,  the  vessel  contracts, 
and  propels  its  contents  in  succession  along  its  course  to  the  ultimate  destination.— 
Chapman. 
*  See  APPENDIX,  Note  Q 


132 

limbs,  in  which  they  arc  best  protected  against  external  injuries.  The 
lymphatics  of  the  parietes  of  the  great  cavities,  those  of  the  viscera 
which  these  cavities  contain,  are  likewise  in  two  layers,  the  one  super- 
ficial, the  other  deep  seated*. 

The  absorbents  differ,  likewise,  from  the  blood-vessels,  in  their  singu- 
larly tortuous  course,  their  frequent  communications,  and  especially  in 
their  unequal  size  in  different  parts  of  their  extent.  An  absorbent,  of  very 
small  dimensions  frequently  enlarges,  so  as  to  equal  in  size  the  thoracic 
duct,  then  contracts  and  again  bulges  out,  though  in  the  length  of  the  ves- 
sel in  which  these  differences  of  size  may  have  been  noticed,  it  may  have 
received  no  collateral  branches.  The  lymphatics,  when  completely  fill- 
ed with  quicksilver,  appear  to  cover  the  whole  surface  of  our  organs; 
and  the  whole  body  seems  enveloped  in  a  net-work  of  close  and  small 
meshes.  The  metastasi§"of  humours,  from  one  part  of  the  body  to  an- 
other at  a  distance,  is  easily  understood  by  any  one  who  has  seen  those 
numerous  inosculations,  rendered  manifest  by  injection.  Metastasis 
ceases  to  be  an  inexplicable  phenomenon;  one  has  no  difficulty  in  con- 
ceiving, how  by  means  of  the  lymphatics  all  the  parts  of  the  body  com- 
municate freely;  how,  fluids  absorbed  by  those  vessels  in  one  part,  may 
be  conveyed  into  another,  and  pervade  the  whole  body,  without  follow- 
ing the  circuitous  route  of  the  circulation,  and  that  it  is,  therefore,  not 
altogether  impossible,  however  improbable,  that  fluids  taken  into  the 
stomach,  may  be  conveyed  directly  from  the  stomach  to  the  bladder,  and, 
that  in  the  same  manner,  the  milk  of  the  intestinal  canal  may  find  its  way 
into  the  breast;  and  that  pus  may  be  removed  from  the  place  in  which  it 
is  collected,  and  be  conveyed  to  the  place  to  which  irritation  calls  it 
forth.  All  that  Bordeau  has  said  of  the  oscillations  and  currents  of  hu- 
mours, through  the  cellular  texture,  in  his  "  Researches  on  the  Mucous 
Tissue,"  may  be  equally  explained  by  the  anatomosis  of  the  lympha- 
tics. 

A  young  man  whom  I  had  ordered  to  rub  in  mercury,  along  the  inner 
part  of  his  left  leg  and  thigh,  for  the  cure  of  a  pretty  large  bubo,  was  af- 
fected, on  the  third  day,  with  salivation,  though  he  used  only  half  a  dram 
of  ointment  at  each  friction.  The  salivary  glands  on  the  left  side,  were 
alone  swollen,  the  left  side  of  the  tongue  was  covered  with  aphthae,  and 
the  right  side  of  the  body  remained  unaffected  by  the  mercurial  action; 
a  clear  proof,  that  the  mercury  had  been  carried  to  the  mouth,  along  the 
left  side  of  the  body,  without  entering  into  the  course  of  the  circulation, 
and  perhaps,  without  passing  through  any  of  the  conglobate  glands;  for, 
that  of  the  left  groin,  which  alone  was  swollen,  did  not  sensibly  diminish 
in  size.  Salivation  may,  therefore,  take  place,  in  the  cure  of  the  vene- 
real disease,  though  none  of  the  mercury  enter  the  circulation,  which 
warrants  the  opinion,  that  the  action  of  syphilis,  as  well  as  of  the  reme- 
dies which  are  administered  for  its  removal,  operates  chiefly  on  the  lym- 
phatic system. 

XLIV.  If  the  fluids  absorbed  by  these  vessels,  can,  in  consequence  of 
their  numerous  inosculations,  pervade  all  parts  of  the  body,  without  mix- 
ing with  the  blood,  not  a  drop  can  enter  the  course  of  the  circulation, 
without  having  previously  passed  through  the  glandular  bodies  that  lie  in 
the  course  of  the  lymphatics ;  dispersed  like  those  vessels  in  all  parts  of 

*  See  APPENDIX,  Note  Q,  for  observations  on  the  structure,  and  functions  of  the 
absorbent  system. 


133 

*he  body,  seldom  insulated,  but  in  clusters  in  the  hollows  of  the  ham, 
the  arm-pit,  in  the  bends  of  the  groin  and  elbow,  along  the  iliac  vessels, 
the  aorta  and  the  blood-vessds  of  the  neck,  around  the  base  of  the  jaw 
and  of  the  occiput,  behind  the  sternum,  along  the  internal  mammary 
vessels,  lastly,  within  the  mesentery,  in  which  their  number  and  size  bear 
a  proportion  to  the  quantity  of  absorbents  which  pass  through  them. 
These  reddish  glands*  varying  in  size, of  an  oval  or  globular  form,  have 
two  extremities,  the  one  at  which  the  lymphatics  enter  :  they  are  then 
called  "  ajferentia"  and  the  other  extremity  turned  towards  the  thoracic 
duct,  which  sends  out  vessels,  fewer  in  number,  but  of  a  larger  size,  and 
called  u  efftrentia"  from  their  use. 

The  lymphatics,  on  reaching  the  glands,  divide,  unite  again  and  inos- 
culate, they  likewise  bend  back  on  themselves,  and  thus  form  the  tissue 
of  the  conglobate  glands,  which  are  merely  clusters  of  coiled  vessels, 
united  by  cellular  tissue,  in  which  blood-vessels  are  distributed,  so  as  to 
occasion  their  reddish  colour.  The  coats  of  the  lymphatics  are  thinner 
in  the  glands  than  elsewhere;  and  their  dilatations,  their  divisions,  and 
their  anastomoses,  are  likewise  more  frequent,  while  they  are  in  the  glan- 
dular tissue.  All  the  lymphatic  vessels,  whose  course  lies  in  the  direc- 
tion of  a  gland,  do  not  enter  its  substance,  several  pass  by  the  gland  and 
embrace  it,  forming  around  it  a  sort  of  plexus,  of  which  the  ramifications 
are  directed  towards  other  glands,  more  in  the  vicinity  of  the  thoracic 
duct.  The  lymphatic  glands  form  so  essential  a  part  of  the  absorbent 
system,  they  produce  on  the  lymph  such  indispensable  changes,  that  no 
lymphatic  vessel  enters  the  thoracic  duct,  without  having  previously 
passed  through  these  glands.  It  even  frequently  happens,  that  the  same 
vessel  passes  through  several  glands,  before  opening  into  that  common 
centre  of  the  lymphatic  system.  Thus,  the  vessels  which  absorb  the 
chyle  of  the  intestinal  tube,  pass  several  times  through  the  glands  of  the 
mesentery.  The  lymphatics  of  the  liver,  situated  very  near  to  the  re- 
ceptaculum  of  Pecquet,  have  been  thought,  by  some  anatomists,  not  to 
follow  that  general  rale ;  but  there  are  uniformly  found,  in  the  course 
of  these  vessels,  glands  which  they  enter.  As,  however,  the  glands  are 
few  in  number,  the  lymph  conveyed  from  the  liver,  is  only  once  subject- 
ed to  the  action  of  the  glands ;  and  this  circumstance  appears  to  me  to 
explain,  in  a  satisfactory  manner,  the  transmission  of  the  colouring  mat- 
ter of  the  bile,  which,  in  jaundice,  manifestly  discolours  the  blood,  in 
which  M.  Deyeux  found  it  by  chemical  analysis. 

XLV.  The  parietes  of  the  lymphatic  vessels  are  formed  of  two  coats, 
both  very  thin  and  transparent,  yet  very  strong,  since  they  support  the 
weight  of  a  column  of  mercury,  which  would  rupture  the  coats  of  arteries 
of  the  same  calibre.  The  internal  coat,  which  is  the  thinner  of  the 
two,  forms  valvular  folds,  arranged  in  pairs,  like  the  valves  of  the  veins, 
and  like  them  preventing  a  retrograde  circulation.  Although  these  coats 
are  very  strong,  and  likewise  very  elastic  and  contractile,  as  they  may 
be  seen  to  contract,  and  to  expel  the  lymph  with  great  impetus,  when 

*  It  is  with  a  view  of  conforming  to  the  language  in  common  use,  that  I  give  the 
name  of  gland  to  those  coils  of  lymphatic  vessels,  which  are  totally  cliff ere nt  from  the 
real  conglomerate  or  secretory  glands.  It  might  be  better,  perhaps,  to  call  them^an^- 
lionsy  as  has  been  done  by  my  learned  and  respected  colleague  Chaussier,  though  that 
name  is  objectionable,  from  its  association  in  the  mind  with  the  nervous  ganglions, 
whose  structure  is  not  at  all  similar  to  that  of  the  lymphatic  ganglions. — Author's  .l\"ot,\ 


134 

the  abdomen  of  a  living  animal*  is  laid  open,  yet  the  course  of  the  lymph 
is  far  from  being  as  rapid  as  that  of  the  blood;  it  even  frequently  appears 
affected  with  irregular  oscillations,  such  as  are  to  be  met  with  in  the  cir- 
culation of  the  blood  through  the  capillary  arteries.  The  numerous  di- 
latations, curvatures  and  anastomoses  of  the  absorbents  must,  in  a  consi- 
derable degree,  impede  the  rapid  progress  of  the  lymph,  but  the  circula- 
tion must  be  retarded,  chiefly  in  the  glands,  as  there  the  vessels  are  most 
convoluted,  dilated,  and  form  the  greatest  number  of  anastomoses,  and 
are  most  subdivided.  Besides,  the  parietes  of  the  absorbents  are  thin- 
nest in  their  passage  through  the  glands,  for,  these  may  be  ruptured  by 
the  weight  of  a  column  of  mercury  which  the  vessels  themselves  are 
able  to  support.  And  the  action  of  these  vessels,  naturally  weaker  in 
that  situation,  is  still  farther  diminished,  by  the  close  cellular  adhesion 
which  unites  together  the  vessels  whose  union  forms  the  glandular  bo- 
dies. 

It  was  necessary  that  the  course  of  the  lymph  should  be  slackened  in 
its  passage  through  the  glands,  in  order  that  it  might  undergo  all  the 
changes  which  those  organs  are  to  produce  upon  it.  Although  we  do 
not  know  precisely  what  those  changes  are,  their  object  appears  to  con- 
sist in  a  more  perfect  union  and  combination  of  its  elements,  and  in  be- 
stowing on  it  a  certain  degree  of  animalization,  as  is  seen,  by  the  greater 
tendency  to  coagulation  of  the  fluid  taken  from  the  vasa  efferentia.  Ano- 
ther object  of  the  passage  of  the  lymph  through  the  glands,  appears  to 
be  to  deprive  it  of  its  heterogeneous  particles,  or  at  least  to  alter  their 
nature,  so  that  they  may  not  become  injurious,  when  they  get  into  the 
mass  of  the  fluids.  The  yellow  colour  of  the  glands  through  which  the 
absorbents  of  the  liver  pass,  the  dark  colour  of  the  bronchial  glands,  the 
red  colour  of  the  mesenteric  glands,  in  animals  which  have  been  fed  on 
madder  or  beet  root,  the  whiteness  of  the  same  glands,  while  the  chyle 
is  passing  through  them,  are  circumstances  which  show,  that  the  glands 
separate,  or  tend  to  separate,  the  colouring  matter  of  the  lymph,  and  that 
if  they  do  not  effectually  prevent  its  transmission  into  the  blood,  it  is  be- 
cause certain  colours,  as  indigo  and  madder,  have  too  much  tenacity, 
•while  other  substances,  as  the  bile,  do  not  pass  through  a  sufficient  num- 
ber of  glands,  to  lose  their  colour  entirely.  The  blood-vessels,  which 
are  very  numerous  in  the  tissue  of  the  conglobate  glands,  pour  into  the 
lymphatics  a  serous  fluid,  which  dilutes  the  lymph,  increases  its  quan- 
tity, and  at  the  same  time  animalizes  it.  The  number  of  the  lymphatic 
glands  is  very  great;  many  are  so  small  as  to  escape  the  eye,  but  become 
enlarged  and  visible,  in  certain  cases  of  disease.  I  have  daily  opportu- 
nities of  observing  in  scrophulous  patients,  swollen  glands,  in  situations 
in  which  anatomists  have  not  pointed  out  any.  The  absorbent  glands 
are,  at  no  time,  so  large  nor  numerous  as  in  infancy.  They  very  frequently 
disappear  in  old  people,  and  it  is  difficult  to  say,  whether  they  have  been 
totally  destroyed,  or  whether  they  are  merely  exceedingly  reduced  in 
bulk. 

*  In  some  cases,  the  activity  of  the  absorbents  appears  increased,  in  a  singular  de- 
gree. Tims,  jaundice  has  been  known  to  be  the  immediate  consequence  of  a  wound  of 
the  liver;  and  on  other  occasions,  a  metastasis  of  humours  has  taken  place,  with  the 
utmost  rapidity.  I  suspect,  that,  in  such  cases,  the  substance  that  has  been  absorbed, 
circulates  by  means  of  the  anastomoses,  and  pervades  the  lymphatics  with  which  the 
whole  body  is  covered,  but  without  passing  through  the  glands^  which  would  slacken 
its  course,  and,  to  a  certain  degree,  alter  its  nature — Author's  Note. 


XL VI.  The  frequent  congestions  of  the  conglobate  glands,  depend  on 
the  stagnation  of  the  lymphatic  fluid  in  their  substance,  and  on  the  com- 
parative weakness  of  the  sides  of  the  vessels  in  these  parts.     The  influ- 
ence of  debilitating  causes  on  the  lymphatic  system,  acts  most  powerfully 
on  the  glands,  which  are  the  weakest  part  of  that  system.     In  such  cases, 
the  vessels  which  enter  into  the  composition  of  the  glands,  act  feebly,  or 
cease  to  act  altogether;  the  fluids,  of  which  there  is  a  continual  acces- 
sion, accumulate;    the  most  liquid    part   alone  penetrates  through  the 
glandular  organ,  the  grosser  particles  remain,  the  humour  thickens,  har- 
dens, and  forms  congestions  of  various  kinds.     If  there  is  a  tendency  to 
cancer,  such  tumours,  at  first  indolent,  become  painful,  the  more  inspis- 
sated matter  being,  in  a  manner,  out  of  the  influence  of  the  vital  power, 
since  its  vessels  are  in  a  state  of  complete  atony,  undergoes  a  sort  of  pu- 
trid fermentation,  the  consequence  of  which  is  a  destruction  and  erosion 
of  the  cellular  tissue,  attended  by  inflammation  of  the  skin  and  neigh- 
bouring parts.     The  tumour  becomes,  an  abcess,  and  discharges  matter 
rendered  liquid  by  the  process  of  fermentation,  and  so  acrid  and  irrita- 
ting,  that  it  extends  the  affection  towards  all  the  parts  with  which  it 
comes  in  contact. 

The  notions  entertained  hitherto  on  cancer,  are,  at  once,  deficient  in 
precision  and  accuracy:  and  it  is  to  their  fallacy,  that  we  are  to  attribute 
the  number  of  contradictory  opinions  on  the  subject  of  its  proper  treat- 
ment. Too  precise  a  distinction  cannot  be  laid  down  betw.een  the  can- 
cerous or  phagedenic  ulcer;  whose  seat  is  always  in  the  skin,  or  in  the 
mucous  membranes  (which  being  mere  prolongation  of  the  skin,  retain 
much  of  its  structure,)  and  those  cancers  which  affect  the  other  parts  of 
the  animal  economy,  especially  the  lymphatic  glands,  the  testicles,  and 
the  breasts.  In  the  cancerous  ulcers,  peculiarly  frequent  in  the  face,  the 
lips,  the  tongue,  in  the  inner  coat  of  the  stomach,  of  the  rectum,  and  of 
the  uterus,  the  parts,  affected  with  inflammation  of  a  malignant  kind,  are 
destroyed,  without  any  means  of  checking  the  progress  of  that  destruc- 
tive action,  the  cause  of  action  is  easily  conceived,  while  in  true  cancer, 
the  glandular  tumefaction  always  precedes  the  cancerous  diathesis. 
As  long  as  the  affection  consists  merely  in  the  obstruction  of  the  vessels, 
by  indurated  lymph,  the  tumour  is  indolent,  and  is  yet  only  a  schirrus ; 
but  soon  all  trace  of  organization  is  lost  in  the  tumefied  part,  the  rup- 
tured vessels  are  lost  in  the  mass  of  different  substances;  the  process  of 
fermentation  which  takes  place,  converts  every  part  into  a  greyish  pulpy 
substance,  in  which  the  most  expert  eye  can  discover  no  organization, 
and  no  distinction  of  parts.  Whenever  this  cancerous  destruction  of 
parts  occurs,  whether  the  whole  organ  is  affected,  or  whether  the  disease 
extends  only  to  a  few  points,  extirpation  is  the  only  remedy  to  be  em- 
ployed; it  is  absolutely  necessary,  that  a  surgical  operation  should  rid 
the  constitution  of  a  part  in  which  organization  and  life  no  longer  exist. 

The  lymphatic  glands  which  swell  in  the  vicinity  of  cancerous  tumours, 
have  already  received,  by  means  of  the  absorbents,  the  destructive  germ, 
and  must  be  removed,  with  the  rest  of  the  diseased  part,  that  the  opera- 
tion may  be  attended  with  the  greater  prospect  of  success.  It  is  very 
true,  that  open  cancers  of  the  breast  may,  for  a  long  time,  discharge 
putrid  matter,  without  inducing  a  cancerous  affection  of  the  glands  of 
the  axilla.  But  may  not  the  discharge,  in  this  case,  act  on  the  principle 
of  revulsion;  and  besides,  what  shall  we  oppose  to  experience,  which 
shows  that  these  glands,  if  not  removed  along  with  the  cancerous  breast, 


136 

soon  become  affected  with  cancer.  If  the  nature  of  the  work  did  Hot 
circumscribe  me,  within  certain  limits,  I  should  point  out  several  other 
particulars  relative  to  the  history  of  cancer,  and  among  other  cases,  in 
my  own  practice,  I  should  relate  that  of  a  woman,  in  whom  I  removed  a 
cancerous  tumour  situated  on  the  left  side  of  the  chest:  this  case  is  re- 
markable from  the  number  of  operations  which  her  disease  required,  and 
for  which  M.  Pelletan  removed,  six  years  ago,  the  left  breast,  and,  three 
years  ago,  a  gland  under  the  axilla  of  the  same  side. 

The  difference  in  the  termination  of  glandular  swellings  and  those 
arising  from  cancer  scrophula,  or  syphilis,  makes  it  probable,  that  there 
exist  ferments,  or  specific  poisons,  which  dispute  the  accumulated  mat- 
ter to  undergo  peculiar  changes. 

The  venereal  virus,  absorbed  by  the  lymphatics  of  the  organs  of  gene- 
ration, remains,  for  some  time,  in  the  glands  of  the  groin,  before  it  ex- 
tends beyond,  as  is  proved  by  the  cure  of  the  venereal  disease,  by  extir- 
pating the  diseased  glands.  In  short,  the  impediment  which  the  lymph 
meets  with,  in  passing  through  the  glands,  shows  why  these  parts  are  so 
frequently  the  seat  of  critical  abcesses,  by  which  we  judge  of  the  nature 
of  several  fevers  of  a  malignant  kind.  In  the  plague  of  eastern  countries, 
the  virus  that  attends  this  dreadful  malady,  is  disseminated  throughout 
the  body,  collects  in  the  glands,  is  transmitted  through  them  with  diffi- 
culty, brings  on  an  irritation  and  gangrenous  inflammation,  terminating 
in  pestilential  buboes. 

XLVII.  The  thoracic  duct  may  be  considered  as  the  centre  in  which 
the  whole  lymphatic  system  terminates;  it  arises  at  the  upper  part  of 
the  abdomen,  from  the  union  of  the  chylous  vessels  with  the  lymphatics 
coming  from  the  inferior  extremities.  At  the  part  where  all  these  vessels 
meet,  there  is  a  dilatation,  a  sort  of  ampullula,  called  lumbar  cistern,  re- 
ceptaculum  chyli,  or  of  Pecquet,  which,  in  truth,  is  not  always  found,  and 
the  size  of  which  is  very  variable.  The  thoracic  duct  enters  the  chest 
through  the  opening  in  the  diaphragm  which  transmits  the  aorta;  it  then 
ascends  along  the  spine,  on  the  right  side  of  the  aorta,  within  the  poste- 
rior mediastinum.  At  the  upper  part  of  the  chest,  opposite  to  the  seventh 
cervical  vertebra,  it  inclines  from  the  right  to  the  left  side,  passes  behind 
the  oesophagus  and  the  trachea,  and  o,:>ens  into  the  subclavian  vein  of  the 
left  side,  at  the  back  part  of  the  insertion  of  the  internal  jugular  into  that 
vein.  While  the  thoracic  duct  is  ascending  along  the  spine,  it  receives 
the  lymphatics  of  the  parietes  of  the  chest;  those  of  the  lungs  enter  it  as 
it  passes  behind  the  root  of  these  organs.  In  its  course  from  the  right 
towards  the  left  side,  it  receives  the  absorbents  of  the  right  upper  ex- 
tremity, and  those  of  the  right  side  of  the  head  and  neck.  Lastly,  it 
unites  with  those  vessels  which  are  coming  from  the  left  side  of  the  head 
and  neck,  as  well  as  from  the  left  upper  extremity,  just  before  opening 
into  the  subclavian  vein.  The  thoracic  duct  sometimes  has  its  insertion 
in  the  jugular  vein  of  the  same  side,  and  not  unfrequently  the  lymphatics 
of  the  right  side  of  the  chest,  neck,  and  head,  and  of  the  right  upper  ex- 
tremity, unite  to  form  a  second  duct,  which  opens  separately  into  the 
right  subclavian  vein.*  Whatever  be  the  vein  into  which  the  duct  opens, 

*  In  some  rare  cases,  lymphatic  vessels,  in  other  parts  of  the  body,  are  seen  to  open 
into  neighbouring  veins.  This  enables  one  to  account  for  the  presence  of  the  chyle 
which  is  said  to  have  been  found  in  the  meseraic  veins,  into  which  it  had  been  poured 
by  some  lacteal.  Mascagni  was  aware  of  this  anatomical  fact.  The  lymphatic  system 


w 

ks  structure  is  the  same  as  that  of  the  lymphatics,  and  its  inner  part  is 
furnished  with  valvular  folds.  Its  increase  of  size  is  not  progressive,  as 
it  approaches  towards  its  termination;  on  the  contrary,  there  are.  seen, 
here  and  there,  dilatations  of  diffeient  sizes,  separated  by  proportionate 
contractions.  Sometimes,  it  divides  into  several  vessels  which  ioosculate 
and  form  lymphatic  plexuses.  The  opening  at  which  the  thoracic  duct 
enters  the  subclavian  vein,  is  furnished  with  a  valve,  better  calculated  to 
prevent  the  flow  of  blood  into  the  lymphatic  system,  than  to  moderate  the 
too  rapid  flow  of  the  lymph  into  the  torrent  of  circulation.  Compres- 
sion of  the  thoracic  duct,  in  aneurism  of  the  heart  and  aorta,  gives  rise  to 
several  kinds  of  dropsy,  a  disease  always  depending  on  the  loss  of  equi- 
librium, between  the  processes  of  inhalation  and  exhalation,  either  from 
increased  action  of  the  exhalants,  or  from  the  absorbents  refusing  to  take 
up  the  lymph,  in  consequence  of  obstruction  in  the  glands,  or  01  com- 
pression of  the  duct. 

XL VIII.  The  nature  of  the  lymph  is  far  from  being  as  well  under- 
stood, as  that  of  the  vessels  along  which  it  circulates.  Haller  considers 
it  as  very  analogous  to  the  serum  of  the  blood,  and  says,  that  this  sub- 
stance, to  which  he  frequently  gives  the  name  of  lymph,  is  like  the  fluid 
contained  in  the  absorbents,  slightly  viscous  and  saltish;  that  heat,  alco- 
hol, and  the  acids  coagulate  it;  in  short,  that  it  possesses  all  the  qualities 
of  the  albuminous  fluids.  The  serum  of  the  blood  exhaled,  throughout 
the  extent  of  the  internal  surfaces,  and  even,  within  the  substance  of  our 
organs,  by  the  capillary  arteries,  is  absorbed  by  the  lymphatics,  and  is 
one  of  the  principal  sources  of  the  lymph,  which  resembles  it  much.  It 
may  be  conceived,  however,  that  the  nature  of  the  lymph  must  be  much 
more  compound  than  that  of  the  serum  of  the  blood,  since  the  lymphatic 
which  absorb,  almost  indiscriminately,  every  kind  of  substance,  take  up 
what  comes  off  from  our  organs,  and  the  recrementitious  parts  of  our 
fluids;  and  these  are  sometimes  recognizable  in  the  absorbents,  when 
marked  by  striking  qualities,  as  fat  by  its  not  mixing  with  aqueous  fluids, 
and  bile  by  its  deep  yellow  colour. 

The  chyle,  which  is  necessarily  affected  by  the  various  kinds  of  food 
which  we  use,  has  different  appearances  in  the  same  persons,  varying 
according  to  the  quality  of  the  different  substances  on  which  we  feed ; 
indigo  gives  it  a  blue  colour;  it  is  reddened  by  madder  and  beet  root, 
and  is  changed  to 'green,  by  the  colouring  matter  of  several  vegetables, 
Sec.  In  a  great  number  of  experiments  performed  on  living  animals,  it 
has  always  appeared  to  me,  such  at  it  is  described  by  authors,  white, 
with  a  slight  viscidity,  and  very  like  milk,  containing  a  very  small  quan- 
tity of  flour.  It  is  easy  to  collect  a  certain  quantity  of  chyle,  by  tying  the 
thoracic  duct  of  a  large  dog,  of  a  sheep,  or  even  of  a  horse,  as  was  done 
several  times  at  the  veterinary  school  at  Alfort.  This  fluid,  when  ex- 
posed to  the  air,  on  cooling,  separates  into  two  parts;  the  one,  forming 
a  kind  of  gelatinous  coagulum,  very  thin  and  not  unlike  the  buffy  coat  of 
inflammatory  blood;  the  other,  in  greater  quantity  and  liquid,  rising 
above  the  coagulum,  on  its  being  detached  from  the  sides  of  the  cup  to 
which  it  adheres.  The  coagulated  mass  is  semi-transparent,  of  a  light 

is,  however,  the  most  subject  to  deviations  of  any  in  the  animal  economy. — Author's 
Note. 

The  fact  referred  in  the  above  note  also  explains  the  appearance  of  certain  sub- 
stances in  the  blood,  after  the  thoracic  duct  has  been  tied. — Godman. 

S 


138 

pink  colour,  does  not  resemble  the  curd  of  milk,  so  that  all  that  has  been 
said  by  a  few  modern  physiologists,  the  exact  resemblance  which  they 
have  pretended  to  discover  between  milk  and  chyle,  is  totally  void  of 
foundation. 

The  lymph,  which  constantly  unites  with  the  chyle,  before  the  latter 
enters  the  san'guiferous  system,  on  being  received  into  a  vessel  by  Mas- 
cagni,  coagulated  in  the  space  of  seven- or  ten  minutes,  turned  sour,  and 
soon  separated  into  two  parts,  the  one  more  abundant,  serous,  in  the 
midst  of  which  there  floated  a  fibrous  coagulum,  which  by  contracting, 
formed  into  a  small  cake  on  the  surface  of  the  fluid.  Hence  he  concludes, 
contrary  to  the  opinion  of  Hew  son,  that  lymph  consists,  for  the  greatest 
part,  of  serum,  and  that  fibrine  constitutes  its  last  part. 

XLIX.  The  practice  of  surgery  in  a  great  hospital,  has  afforded  me 
frequent  opportunities  of  examining  the  lymph  which  is  discharged,  in 
abundance,  from  ulcerated  scrophulous  tumours  in  the  groin,  in  the  ax- 
illa, and  in  various  other  parts  of  the  body.  I  have  always  met  with  a 
liquid  nearly  transparent,  slightly  saline,  coagulable  by  heat,  alcohol,  and 
the  acids.  Small  fibrous  floculi  form,  even  on  the  surface  of  the  cloths 
which  are  wetted  with  it,  and  show  the  existence  of  two  parts,  the  one  a 
gelatino-albuminous  fluid  holding  in  solution  several  salts;  the  other,  in 
smaller  quantity,  is  a  fibrous  substance  which  concretes  spontaneously. 
The  lymph,  in  man  and  the  warm-blooded  animals,  appears  to  me,  in 
every  respect  similar  to  the  fluid  which  is  contained  in  the  vessels  of 
white-blooded  animals.* 


*  The  subject  of  absorption  has  of  late  excited  a  very  lively  interest,  and  lias  been 
elucidated  considerably  by  the  experiments  of  Tiedemann  and  Gmelin,  in  Germany, 
Magendie  and  Flandrin,  in  France,  and  Lawrance  and  Coates,  in  Philadelphia. 

The  conclusions  drawn  from  the  experiments  of  Tiedemann  and  Gmelin  are,  that  the 
alimentary  matters,  the  smelling,  saline,  colouring,  and  metallic  substances  taken  into 
the  stomach  and  intestinal  canal,  after  being  mixed  with  several  fluids,  separated  from 
the  mass  of  the  blood  to  promote  assimilation ;  such  as  the  saliva,  the  gastric  juice,  and 
the  bile,  may  pass  into  the  mass  of  the  blood  by  several  channels  :  1st.  Through  the  ab- 
sorbents and  the  thoracic  duct.  2d.  Through  absorbents  which  are  united  with  veins 
in  the  mesenteric  glands.  3d.  Through  the  roots  of  the  venaportje.  Those  substances 
which  are  conveyed  into  the  sanguiferous  system,  through  the  thoracic  duct,  as  chyle, 
are  mixed,  in  their  pussage  through  the  mesenteric  glands  and  the  thoracic  duct,  with 
a  reddish  coagulating  fluid,  secreted  from  the  arterial  blood  in  these  glands,  and  in  the 
spleen,  which  brings  the  chyle  to  resemble  blood.  The  substances,  however,  which 
are  carried  to  the  vena  portze,  are  assimilated  to  the  mass  of  the  blood,  by  being  mixed 
with  venous  blood,  and  by  the  change  which  they  suffer  in  consequence  of  the  secre- 
tion of  the  bile.  See  Phil.  Med.  Jour.  vol.  iii.  p.  149. 

The  experiments  instituted  by  the  Philadelphia  Academy  of  Medicine,  and  performed 
by  Drs.  Lawrance  and  Coates,  led  to  the  following  conclusions,  which  being  drawn 
after  the  repetition  of  those  by  Magendie,  render  it  unnecessary  to  make  a  particular 
reference  to  those  of  that  gentleman.  The  American  experimenters  think  that  they 
have  established  the  following  conclusions :  1st.  That  colouring  matters  are  not  ab- 
sorbed by  the  lacteals  in  the  living  body.  2d.  That  camphor  is  absorbed  with  much 
irregularity,  and  in  too  small  quantity  to  afford  proof  of  the  route  of  absorption.  3d. 
That  assafoetida  is  permeating.  4th.  That  prussiate  of  potass  enters  by  the  lacteals  and 
ductus  thoracicus.  5th.  That  mix  vomica  and  prussic  acid  destroy  life  by  their  opera- 
tions on  the  nerves,  and  probably  in  no  other  way.  6th.  That  the  assertion  of  Magen- 
die, that  ink  will  infiltrate  in  the  living  body,  is  incorrect.  7th.  That  the  odour  of 
camphor,  assafoetida,  and  mint,  infiltrate  through  the  intestines.  8th.  That  the  chemi- 
cal and  odoriferous  substances  just  enumerated,  are  transmitted  into  the  system  with 
much  more  delay  and  difficulty  from  the  stomach  than  from  the  intestinal  tube,  and 
wjth  still  less  from  the  serous  cavity  of  the  abdomen.  See  Phil.  Med.  Jour.  vol.  iii. 
p.  273. 


139 


CHAPTER   III. 


OF  THE  CIRCULATION. 

L.  THE  term  circulation  is  applied  to  that  motion  by  which  the  blood, 
setting  out  from  the  heart,  is  incessantly  carried  to  all  parts  of  the  body 
by  means  of  the  arteries,  and  returns  by  the  veins,  to  the  centre  whence 
it  began  its  circuit. 

The  uses  of  this  circulatory  motion,  are  to  expose  the  blood,  changed 
by  mixing  with  the  lymph  and  the  chyle,  to  the  air  in  the  lungs  (respira- 
tion^) to  convey  it  to  several  viscera,  in  which  it  passes  through  different 
steps  of  purification  (secretions  /)  and  to  send  it  into  the  organs  whose 
growth  is  to  be  promoted,  or  whose  losses  are  to  be  repaired,  by  the  nu- 
tritive and  acimalized  part  of  the  blood  brought  into  a  state  of  perfection 
by  these  successive  processes  (nutrition.'] 

The  circulatory  organs  are  less  useful  in  elaborating,  than  in  convey- 
ing the  fluids.  To  form  a  just  conception  of  their  uses,  one  may  com- 
pare them  to  those  workmen  in  a  large  manufactory  in  which  various 
kinds  of  goods  are  made,  who  are  employed  in  carrying  the  materials 
to  those  who  are  to  work  them;  and  as  among  the  latter,  some  finish  the 
work,  while  others  prepare  the  materials,  so  the  lungs  to  the  secretory 
glands  are  continually  occupied  in  separating  from  the  blood  whatever  is 
too  heterogeneous  to  our  nature  to  become  assimilated  to  our  organs,  or 
to  afford  them  nourishment. 

To  understand,  thoroughly,  the  mechanism  of  this  function,  it  is  neces- 
sary to  study  separately  the  action  of  the  heart,  that  of  the  arteries  which 
arise  from  it,  and,  lastly,  that  of  the  veins  which  enter  it.  The  union  of 
these  three  classes  of  organs,  forms  the  circle  of  the  circulation. 

LI.  Of  the  action  cf  the  heart.  In  man,  and  in  all  warm-blooded  ani- 
mals, the  heart  is  a  hollow  muscle,  the  inner  part  of  which  is  divided  into 
four  large  cavities  which  communicate  with  one  another ;  from  these, 
vessels  arise  which  convey  the  blood  to  all  parts  of  the  body,  and  the  ves- 
sels which  bring  it  back  from  all  those  parts,  likewise  terminate  in  these 
cavities. 

The  heart  is  placed  in  the  chest,  between  the  lungs,  above  the  dia- 
phragm, whose  motions  it  follows;  it  is  surrounded  by  the  pericardium, 
a  dense  and  fibrous  membrane  admitting  of  very  slight  extension,  closely 
united  to  the  substance  of  the  diaphragm,  covering  the  heart  and  great 
vessels,  without  containing  them  in  its  cavity,  furnishing  an  external  co- 
vering to  the  heart,  and  bedewing  its  surface  with  a  serous  fluid,  which 
never  accumulating,  except  in  disease,  facilitates  its  motion,  and  prevents 


An  admirable  series  of  experiments  were  subsequently  performed  by  Dr.  J.  O'B. 
Lawrance,  and  Dr.  B.  II.  Coates,  in  which  they  very  clearly  establish,  that  articles 
taken  into  the  stomach  may  escape  by  three  outlets  for  absorption.  By  the  vena  portae, 
the  cesophageal  veins,  and  the  thoracic  duct ;  and  if  all  these  be  closed,  the  absorbed 
matter  no  longer  finds  its  way  into  the  circulation  or  urine.  See  Phil.  Med.  Jour.  vol. 
v.  p.  327 — Godman. 

See  APPENDIX,  Note  Q. 


140 

its  adhering  to  the  neighbouring  parts.  The  principal  use  of  the  peri' 
cardium,  is  to  fix  the  heart  in  its  place,  to  prevents  its  being  displaced 
into  other  parts  of  the  chest,  which  could  not  happen,  without  occasion- 
ing a  fatal  disorder  in  the  circulation.  If,  after  having  laid  open  the 
chest  of  a  living  animal,  by  raising  the  sternum,  an  incision  is  made  into 
the  pericardium,  the  heart  protrudes  through  the  opening,  and  moves  to 
the  right  and  left  by  bending  itself  on  the  origin  of  the  large  vessels  ;  the 
course  of  the  blood  is  then  intercepted,  and  the  animal  threatened  with 
immediate  suffocation. 

In  man,  the  heart  is  placed  nearly  towards  the  union  of  the  upper 
third  of  the  body,  with  the  lower  two-thirds;  it  is,  therefore,  nearer  to 
the  upper  parts;  it  holds  them  under  a  more  immediate controul,  and  as 
that  organ  keeps  up  the  action  of  all  the  rest,  by  the  blood  which  it  sends 
into  them,  the  parts  above  the  diaphragm  have  much  more  vitality  than 
the  parts  beneath.  The  skin  of  the  upper  part  of  the  body,  and  espe- 
cially of  the  face,  has  more  colour,  and  is  warmer  than  that  of  the  lower 
parts;  the  phenomena  of  diseases  come  on  more  rapidly  in  the  upper 
parts;  they  are,  however,  less  liable  to  put  on  a  chronic  character. 

The  bulk  of  the  heart,  compared  to  that  of  other  parts,  is  larger  in  the 
foetus,  than  in  the  child  that  has  breathed;  in  short  men,  than  in  those  of 
high  stature.  The  heart  is  likewise  larger,  the  stronger,  and  more  pow- 
erful in  courageous  animals  than  in  weak  and  timid  creatures. 

This  is  the  first  instance  of  a  moral  quality  depending  on  a  physical 
disposition  of  parts ;  it  is  one  of  the  most  striking  proofs  of  the  influence 
of  the  moral  character  of  man  on  his  physical  nature.  Courage  arises 
out  of  the  consciousness  of  strength,  and  the  latter  is  in  proportion  to 
the  activity  with  which  the  heart  propels  the  blood  towards  all  the  or- 
gans. The  inward  sensation  occasioned  by  the  afflux  of  the  blood,  is  the 
more  lively,  and  the  better  felt,  when  the  heart  is  powerful.  It  is  on  that 
account  that  some  passions,  for  example,  anger,  by  increasing  the  ac- 
tion of  the  heart,  increase  a  hundred  fold  both  the  strength  and  courage, 
while  fear  produces  an  opposite  effect.  Every  being  that  is  feeble,  is 
timorous,  shuns  danger,  because  an  inward  feeling  warns  him,  that  he 
does  not  possess  sufficient  strength  to  resist  it.  It  may  perhaps  be  ob- 
jected, that  some  animals,  as  the  turkey  cock  and  the  ostrich,  possess 
less  courage  than  the  least  bird  of  prey,  that  the  ox  has  less  than  the  lion 
and  other  carnivorous  animals.  What  has  been  said  does  not  apply  to 
the  absolute,  but  to  the  relative  size  of  the  heart.  Now,  though  the  heart 
of  a  hawk  be  absolutely  smaller  than  that  of  a  turkey  cock,  it  is  neverthe- 
less larger,  in  proportion  to  the  other  parts  of  the  animal.  Besides,  the 
bird  of  prey,  like  the  other  carnivorous  animals,  in  part  owes  his  courage 
to  the  strength  of  his  weapons  of  offence. 

Another  objection,  more  specious,  but  not  better  founded,  is  drawn 
from  the  courage  manifested,  on  certain  occasions,  by  the  most  timid 
animals,  for  example,  by  the  hen  in  protecting  her  young ;  from  the 
courage  with  which  other  animals  pressed  by  hunger  or  lust,  surmount 
all  obstacles,  but  particularly  from  the  heroic  valour  of  men  of  the  most 
feeble  bodies.  All  these  facts,  however,  are  only  proofs  of  the  influence 
of  the  mind  on  the  body.  In  civilized  man,  the  prejudices  of  honour,  in- 
terested considerations,  and  a  thousand  other  circumstances,  degrade 
the  natural  inclinations  of  man,  so  as  to  make  a  coward  of  one  whose 
strength  is  such  as  would  induce  him  to  brave  all  kinds  of  dangers,  while 
on  the  other  hand,  men  whose  organization  should  render  them  most 


141 

timid,  arc  inspired  to  perform  the  most  daring  actions.  But  all  these 
passions,  all  these  moral  affections,  operate  only  by  increasing  the  action 
of  the  heart,  by  increasing  the  frequency  and  the  force  of  its  pulsations, 
so  that  it  excites  the  brain  or  the  muscular  system,  by  a  more  abundant 
supply  of  blood. 

The  heart  is  not  quite  ovoid  in  man  as  it  is  in  several  animals,  nor  is  it 
parallel  to  the  vertebral  column,  but  it  lies  obliquely,  and  is  flattened  to- 
wards the  side  next  the  diaphragm  on  which  it  rests. 

Of  the  four  cavities  which  form  the  heart,  two  are,  in  a  measure,  ac- 
cessary, viz.  the  auricles;  they  are  small  musculo-membranous  bags  op- 
posed to  each  other,  receiving  the  blood  of  all  the  veins,  and  pouring  that 
fluid  into  the  ventricles  at  the  base  of  which  the  auricles  are,  as  it  were, 
applied.  The  ventricles  arc  two  muscular  bags  separated  by  a  partition 
of  the  same  nature,  and  belonging  equally  to  both  ;  they  form  the  greatest 
part  of  the  heart,  and  give  origin  to  the  arteries. 

The  auricle  and  ventricle  on  the  right  side,  are  larger  than  those  on 
the  left.  But  that  difference  of  size  depends  as  much  on  the  manner  in 
which  the  blood  circulates,  at  the  approach  of  death,  as  on  the  original 
conformation  of  the  lungs.  On  the  point  of  death,  the  lungs  expand  with 
difficulty,  and  the  blood  sent  into  them,  by  the  contractions  of  the  right 
ventricle,  being  no  longer  able  to  circulate  through  them,  collects  in  that 
cavity,  flows  back  into  the  right  auricle,  in  which  the  veins  continue  to 
deposit  blood,  stretches  their  parietes,  and  increases  considerably  the  di- 
mensions of  those  cavities.  The  capacity  of  the  right  cavities  is,  how- 
ever, originally  greater  than  that  of  the  left,  and  is  proportioned  to  that 
of  the  venous  system  which  opens  into  it.  The  right  cavities  of  the 
heart,  which  might  be  called  its  venous  cavities,  have  likewise  thinner 
parietes  than  the  left  or  arterial,  and,  in  this  respect,  the  same  difference 
is  observed,  as  in  the  parietes  of  the  arteries  and  veins.  The  right  ven- 
tricle having  to  send  the  blood  destined  to  the  lungs,  to  a  very  short  dis- 
tance, and  through  a  tissue  easily  penetrated,  requires  but  a  moderate  im- 
pelling force. 

As, will  be  shown,  in  speaking  of  respiration,  a  function  of  which  the 
physiological  history  is  not  easily  separated  from  that  of  the  circulation, 
the  heart  may  further  be  considered  as  formed  of  two  parts  in  contact, 
the  one  right  or  venous,  the.  other  left  or  arterial.  Notwithstanding  the 
juxta  position  of  these  two  parts  of  the  same  organ,  they  are  perfectly 
distinct,^  and  the  blood  in  each  cavity  is  very  different  from  that  in  the 
other.  The  blood,  in  the  adult,  can  never  pass  immediately  from  the 
one  to  the  other;  the  right  side  of  the  heart  receives  the  blood  of  the 
•whole  body,  and  transmits  it  to  the  lungs;  the  left  side  of  the  heart  re- 
ceives the  blood  of  the  lungs,  and  distributes  it  over  the  whole  body,  so 
that,  in  a  physiological  point  of  view,  the  lungs  form  a  part  of  the  circle 
of  the  circulation,  and  serve  as  an  indispensable  medium  between  the 
two  divisions  of  the  heart,  and  as  will  be  seen  hereafter,  their  part  of  the 
circle  is,  by  no  means,  the  least  important. 

If  there  existed,  between  the  ventricles,  a  direct  communication,  the 
venous  blood  would  mix  with  the  arterial,  and  the  union  of  these  two 
fluids  would  mutually  impair  the  qualities  of  each.  Recent  observations 
have  furnished  an  opportunity  of  judging  of  the  effects  of  such  a  commu- 
nication between  the  ventricles,  which  had  been  imagined  by  the  ancients, 
but  of  which  no  case  had  yet  been  met  with.  A  man,  forty-one  years  of 
age,  came  to  the  Hopital  de  la  Charite,  to  undergo  the  operation  of  litho- 


142 

tomy.  He  was  remarkable  for  the  lividity  of  his  complexion, the  turges- 
cence  of  the  vessels  of  the  conjunctiva,  and  the  thickness  of  his  lips, 
which  like  the  rest  of  his  face,  were  of  a  dark  colour,  his  respiration 
was  laborious,  his  pulse  irregular,  he  could  not  utter  two  words  in  suc- 
cession without  taking  breath  ;  was  obliged  to  sleep  in  a  sitting  posture, 
and  was  particularly  remarkable  for  his  indolence.  This  indolence,  join- 
ed to  great  simplicity  of  nature,  was  such,  that  he  had  never  been  able  to 
maintain  himself  without  the  assistance  of  his  wife.  A  very  small  quan- 
tity of  blood  was  taken  from  his  arm,  in  consequence  of  which  his  pains 
were  diminished,  but  his  difficulty  of  breathing  increased,  was  followed 
by  syncope,  and  he  died  from  suffocation.  On  opening  his  body,  his  heart 
was  found  filled  with  blood,  and  especially  the  right  auricle,  which  was 
considerably  distended ;  the  pulmonary  artery  was  aneurismal,  and  uni- 
formly distended  from  the  right  ventricle,  to  its  division  ;  none  of  its 
coats  had  yet  given  way.  The  two  ventricles  of  the  heart  were  of  nearly 
the  same  capacity,  and  the  relative  thickness  of  their  parietes  did  not 
vary  so  much  as  in  health.  The  partition  between  them,  contained  an 
opening  of  communication  of  an  oblong  shape,  about  half  an  inch  in  ex- 
tent, and  directed  obliquely  from  below  upwards,  from  before  backward, 
and  from  left  to  right,  so  that,  not  only  the  direction  of  the  opening,  but 
likewise  a  kind  of  valve  formed  in  the  right  ventricle,  by  a  fleshy  column, 
so  placed  as  to  prevent  the  return  of  the  blood  into  the  left  ventricle  : 
clearly  showed,  that  the  blood  flowed  from  the  left  into  the  right  ventri- 
cle, and  thence  into  the  pulmonary  artery.  Theductus  arteriosus,an  inch 
in  length,  and  large  enough  to  admit  a  goose  quill,  allowed,  as  in  the  foe- 
tus, a  free  passage  to  the  blood,  from  the  pulmonary  artery  into  the  aorta. 
The  foramen  ovale  was  closed. 

This  singular  conformation  explains,  in  the  most  satisfactory  manner, 
the  phenomena  observed  during  the  life  of  the  patient,  and  the  organic 
affection  of  the  pulmonary  artery.  There  was  necessarily,  in  this  vessel, 
a  mixture  of  venous  and  arterial  blood,  and  this  blood  was  sent  into  it,  in 
part  by  the  action  of  the  left  ventricle,  with  an  increased  impetus,  which 
accounts  for  the  aneurism.  The  blood  which  reached  the  lungs  was  al- 
ready vivified,  and  required  less  action  from  that  organ,  to  complete  its 
oxyd'ation;  on  the  other  hand,  the  right  auricle  emptied  itself,  with  dif- 
ficulty, into  the  right  ventricle,  in  part  filled  with  the  blood  which  the 
left  ventricle  sent  into  it  with  greater  force:  hence  the  extreme  difficulty 
in  the  venous  circulation,  the  lividity  of  the  complexion,  the  colour  and 
the  puffiness  of  the  face,  the  habitual  and  general  torpor.  This  state  of 
langour  and  inactivity  might,  likewise,  depend  on  the  flow  of  the  venous 
blood  into  the  aorta,  along  the  ductus  arteriosus.  It  is  worthy  of  obser- 
vation, however,  that  this  impure  blood  was  not  transmitted  to  the  brain, 
whose  vital  excitement  it  would  not  have  been  able  to  maintain. 
lower  extremities  bore  no  proportion  to  the  upper,  and  this  inequality 
analogous  to  what  is  observed  in  the  foetus,  depended  on  a  similar  cause. 
This  morbid  preparation  was  deposited  by  M.  Deschamps,  in  the  museum 
of  the  Ecole  de  Medicine  of  Paris,  and  was,  by  their  desire,  modelled  in 
wax.  M.  Beauchene,  junior,  presented  the  same  museum  with  a  similar 
preparation,  which  he  procured  from  a  subject  in  the  dissecting  room. 

Several  anatomists  have  paid  attention  to  the  structure  of  the  heart; 
much  has  been  said  on  the  subject  of  the  peculiar  arrangement  of  the 
muscular  fibres  which  form  its  'parietes,  yet,  the  only  result  that  can  be 
obtained  from  all  these  researches  is,  that  it  is  absolutely  impossible  to 


143 

unravel  the  intricacy  of  these  fibres*.  Fibres  of  the  ordinary  structure,' 
and  crossing  each  other,  in  various  directions,  form  the  two  auricles; 
other  and  more  numerous  fibres  form  the  parietesof  the  ventricles,  reach 
from  the  apex  to  the  base,  extend  into  the  septum  which  divides  them, 


*  On  this  point  the  author  is  by  no  means  correct.  The  structure  of  the  heart  may 
be  demonstrated  with  tolerable  accuracy.  The  latest  and  best  description  of  it  has  been 
furnished  by  J.  F.  VAUSS,  teacher  of  anatomy  in  the  University  of  Liege. 

As  an  accurate  view  of  the  distribution  of  its  fibres  is  requisite  to  enable  us  to  know 
the  nature  of  the  actions  of  this  viscus,  the  following  account  by  this  anatomist  is  here 
introduced : — 

"  The  heart  is  a  conical  hollow  muscle,  covered  by  the  serous  membrane,  the  peri- 
cardium— lined  by  a  membrane,  which  is  of  a  different,  nature  in  each  ventricle,  and 
composed  of  three  layers  of  muscular  fibres  :  the  superficial  one  common  to  both  ven- 
tricles—the middle  one  at  least  four  times  as  large  as  the  preceding,  and  like  it,  com- 
mon to  the  two  great  cavities  of  the  heart — and  the  lower  one,  divided  into  two  parts, 
the  right  and  the  left,  each  belonging  to  the  corresponding  ventricle ;  both  of  them 
forming  the  septum  by  their  junction,  and  giving  birth  to  the  column®  carneae. 

"  The  other  layer  is  very  fine  ;  its  bundles  of  fibres  which  become  more  oblique  as 
they  get  lower,  are  directed,  the  anterior  ones  from  the  right  to  the  left,  and  the  pos- 
terior ones  from  left  to  right,  from  the  base  to  the  apex  of  the  heart,  where  they  are 
confounded  with  the  fibres  of  the  middle  layer. 

"  The  fibres  of  the  middle  layer  are  much  more  numerous,  and  follow  the  same  di- 
rection ;  only  they  are  more  oblique,  and  are  not  all  of  them  earned  to  the  apex  of  the 
heart.  The  inferior  fibres  only  reach  the  apex,  and  are  there  confounded  with  the  fibres 
of  the  outer  layers.  Whilst  the  others,  according  as  they  become  more  superficial, 
reach  the  posterior  farrow,  where  the  layer  untwists  itself,  to  form  the  two  unequal 
portions  which  compose  the  lower  layer  of  each  ventricle. 

"  The  lower  layer  of  the  right  ventricle,  which  is  much  thinner  than  that  of  the  left, 
separates  itself  from  the  latter  on  a  level  with  the  posterior  furrow,  and  is  earned  back- 
wards, on  the  outside,  before,  and  then  within  the  ventricle  which  it  immediately  en- 
velopes. All  its  bundles  bencl  from  below  upwards,  and,  crossing  the  direction  of  those 
of  the  middle  layer,  are  fixed,  the  upper  ones,  which  are  almost  transverse,  to  the  cir- 
cumference of  the  auriculo-ventricular  opening,  and  to  the  anterior  part  of  the  mouth 
of  the  pulmonory  artery— the  others,  which  are  longer  and  more  oblique,  and  which 
form  the  right  side  of  the  septum,  successively  to  the  part  of  that  orifice  which  is  be- 
tween the  two  ventricles,  and  to  its  posterior  part. 

"  The  lower  layer  of  the  left  ventricle,  which  is  much  thicker  than  that  of  the  right, 
arises  like  it  from  the  middle  laver,  on  a  level  with  the  posterior  furrow.  Its  bundles 
r^n  from  behind  to  before,  between  the  two  cavities,  thus  forming-  the  left  side  of  the 
septum,  reach  the  anterior  furrow,  then,  running  from  right  to  left,  and  from  below  up- 
wards, they  surround  the  ventricles ;  and,  crossing  the  line  of  the  bundles  of  the  middle 
layer,  are  fixed  successively,  one  by  the  side  of  the  other,  to  the  origin  of  the  aorta,  and 
to  the  opening  of  communication  between  the  ventricle  and  auricle,  all  the  way  to  the 
upper  extremity  of  the  posterior  furrow. 

«*  The  lowest  bundles  on  each  side  alone  follow  a  different  direction.  These  bundles 
after  separating  from  the  others,  approach  the  centre  of  the  corresponding  ventricle, 
and  form  the  columnx  carneae  of  the  heart. 

"  Thus  all  the  fibres  of  the  superficial  layer  take  the  form  of  a  lengthened  spiral, 
which  takes  a  direction  from  the  base  towards  the  apex  of  the  heart,  where  the  fibres 
are  confounded  with  those  of  the  middle  layer,  after  having  made  a  turn  or  a  turn  and 
a  half.  Those  of  the  middle  layer  have  the  same  form,  the  same  general  direction,  and 
the  same  origin  ;  but  they  are  more  oblique,  and  are  so  arranged,  that  one  part  only 
of  them  reach  the  apex  of  the  heart,  whilst  the  greater  part  terminate  at  its  posterior 
furrow.  Those  of  the  last  layer  of  each  ventricle  have  still  a  spiral  form,  but  the  screw 
takes  the  inverse  direction,  for  the  fibres  stretch  from  the  posterior  furrow  to  the  base 
of  the  heart;  and  they  do  not  reach  that  part  until  they  have  surrounded  the  corres- 
ponding ventricle  from  right  to  left,  crdfesing  the  line  of  the  fibres  of  the  two  other  lay- 
ers. The  septum  is  formed  by  the  junction  of  the  two  lower  layers  with  the  addition 
of  a  few  bundles,  which  run  from  the  apex  of  the  heart,  and  appertain  to  the  middle 
and  superficial  layers,  which  are  mixed  together  at  that  part. 

"  The  structure  of  the  auricles  is  less  regular.  In  general,  the  fleshy  fibres  pass  from 


144 

pass  from  the  one  to  the  other,  arid  are  lost  into  each  other,  in  several 
points.  They  are  exceedingly  red,  short,  close,  and  united  by  a  cellular 
tissue,  in  \vhich  fat  scarcely  ever  accumulates. 

These  fibres  forcibly  pressed  against  each  other,  form  a  tissue  similar 
to  the  fleshy  part  of  the  tongue,  endowed  with  but  little  sensibility,  but 
contractile  in  the  highest  degree.  Vessels  and  nerves,  in  considerable 
number,  if  compared  to  the  bulk  of  the  heart,  pervade  this  muscular  tissue, 
whose  contraction,  whatever  in  other  respects  may  be  the  direction  of  its 
fibres,  tends  to  draw  towards  the  centre  of  the  cavities,  every  point  of 
their  parietes.  Lastly,  a  very  fine  membrane  lipes  the  inner  part  of  these 
cavities,  facilitates  the  flow  of  blood,  and  prevents  the  infiltration  of  that 
fluid. 

LII.  If  we  suppose,  for  a  moment,  that  all  the  cavities  of  the  heart  are 
perfectly  emptied  of  blood,  and  that  they  fill  in  succession, the  following 
may  be  considered  as  the  mechanism  of  the  circulation  through  the  heart. 
The  blood  brought  back  from  every  part  of  the  body,  and  deposited  into 
the  right  auricle,  by  the  two  vense  cavse,  and  by  the  coronary  vein,  sepa- 
rates its  parietes  and  dilates  it,  in  every  direction.  The  irritation  attend- 
ing the  presence  of  the  blood,  stimulates  the  auricle  to  contraction;  this 
fluid,  which  is  incompressible,  flows  back,  in  part,  into  the  veins,  but  it 
chiefly  passes  into  the  pulmonary  ventricle,  through  a  large  aperture,  by 
means  of  which  it  communicates  with  the  right  auricle.  The  auricle, 
after  freeing  itself  of  the  blood  with  which  it  is  filled,  relaxes  and  again 
dilates  by  the  accession  of  a  new  supply  of  this  fluid,  continually  brought 
by  the  veins  which  open  into  it. 

However  the  right  ventricle,  filled  with  the  blood  which  it  has  received 
from  the  auricle,  contracts  in  its  turn  on  the  fluid  whose  presence  excites 
its  parietes,  and  tends,  in  part,  to  return  it  into  the  right  auricle,  and  to 
send  it  along  the  pulmonary  artery.  Regurgitation  from  the  ventricle  into 
the  auricle,  is  prevented  by  the  tricuspid  valve,  a  membranous  ring  sur- 
rounding the  edge  of  the  opening  of  communication,  and  the  free  edge  of 
which  is  divided  into  three  divisions,  to  which  are  attached  small  tendons 
terminating  into  the  columnae  carnae  of  the  heart.  Three  valves  laid 
against  the  parietes  of  the  ventricle,  the  instant  the  blood  passes  in  to  its  ca- 
vity, recede  from  them  when  it  contracts,  and  rise  towards  the  auricula^ 
opening.  They  cannot  be  forced  into  the  auricle,  as  their  free  and  loose  edge 
is  kept  in  its  situation  by  the  columnae  carnse,  which  are  like  so  many  little 
muscles  whose  tendons  inserted  into  loose  edges  of  the  valves,  bind  them 
down  when  the  stream  of  blood  tends  to  form  those  membranous  folds 
towards  the  auricles.  The  three  divisions,  however,  of  the  tricuspid 
valve,  by  rising  towards  the  auricular  aperture,  return  into  the  auricle, 
all  the  blood  contained  in  the  inverted  cone  which  they  form,  immediately 
before  rising.  Besides,  these  three  portions  of  the  tricuspid  valve  do  not 
close  completely  the  aperture,  around  which  they  are  placed,  they  are 
perforated  by  a  number  of  small  holes:  a  part  of  the  blood,  therefore,  re- 
turns into  the  auricle,  but  the  greatest  portion  is  sent  into  the  pulmonary 
artery.  The  action  of  this  vessel  begins,  when  the  parietes  of  the  ventri- 


the  circumference  of  the  mouths  of  the  veins,  aftd  from  the  auricolo-ventricular  open- 
ing, to  be  distributed  over  the  parietes,  and  especially  on  the  septum ;  where,  in  the 
situation  of  the  fossa  ovalis,  they  form  two  crescents,  the  concave  parts  of  which  are 
opposed  to  each  other." — Copland. 
For  remarks  on  the  functions  of  the  heart,  see  APPENDIX,  Note  R. 


145 


cal 


are  in  a  state  of  relaxation,  and  the  blood  would  be  forced  back  into 
the  ventricle,  if  the  sigmoid  valves,  by  rising  suddenly,  did  not  prevent 
it.  Supported  on  a  kind  of  floor  formed  by  three  valves,  which  lie  across 
the  calibre  of  the  vessel,  the  blood  pervades  the  tissue  of  the  lungs,  and 
flows  along  the  divisions  of  the  pulmonary  vessels;  from  the  arteries  it 
passes  into  the  veins,  and  these,  four  in  number,  convey  it  into  the  left 
auricle.  This  auricle,  stimulated  by  the  presence  of  the  blood,  contracts 
in  the  same  manner  as  the  right,  part  of  the  blood  flows  back  into  the 
lungs,  but  the  greatest  part  enters  the  last  ventricle,  which  sends  it  along 
the  aorta,  to  every  part  of  the  body,  whence  it  returns  to  the  heart  by  the 
veins.  The  return  of  the  blood  into  the  left  auricle,  is  prevented  by  the 
mitral  valve  which  is  similar  to  the  t-ricuspid,  except  that  its  loose  edge  is 
divided  only  into  two  divisions.  As  soon  as  the  blood  has  reached  the 
aorta,  this  vessel  contracts,  its  sigmoid  valves  fall,  and  the  blood  is  sent 
to  every  part  of  the  body  which  isv supplied  by  some  of  the  innumerable 
branches  of  that  great  artery. 

In  a  natural  state,  the  circulation  is  not  carried  on  as  has  been  just 
stated;  and,  we  have  supposed  this  successive  action  of  the  four  cavities 
of  the  heart,  only  to  render  more  intelligibler'the  mechanism  of  the  circu- 
lation in  that  organ.  If  we  Jay  bare  the  heart  in  a  living  animal,  we  ob- 
serve, that  the  two  auricles  contract  at  the  same  time,  that  the  contrac- 
tion of  the  ventricle  is  likewise  simultaneous,  so  that  while  the  auricles 
are  contracting,  to  expel  the  blood  which  fills  them,  the  ventricles  are 
dilating  to  receive  it.  This  successive  contraction  of  the  auricles  and 
ventricles  is  readily  explained,  by  the  alternate  application  of  the  stimu- 
lus which  determines  the  action  of  these  cavities.  The  blood  which  the 
veins  bring  into  the  auricles,  does  not  excite  their  contraction,  till  a  suf- 
ficient quantity  has  been  collected.  While  this  accumulation  is  taking 
place,  they  yield,  and  the  resistence  which  is  felt  on  touching  them,  dur- 
ing their  diastole,  depends,  almost  entirely,  on  the  presence  of  the  blood 
which  separates  and  supports  their  parietes.  The  same  applies  to  the 
ventricles;  they  cannot  contract,  until  a  sufficient  quantity  of  blood  is 
collected  within  them;  that  there  remains  some  blood  in  these  cavities, 
(for  they  are  never  completely  emptied,)  is  no  objection  to  the  theory; 
since  this  small  quantity  is  not  sufficient  to  bring  on  contraction  of  the 
heart,  and  is  not  worth  taking  into  account. 

If  I  am  asked,  why  the  four  cavities  of  the  heart  do  not  all  contract  at 
once,  I  answer,  that  it  is  easier  to  assign  the  final  than  the  proximate 
cause.  If  the  contraction  of  these  cavities  had  been  simultaneous,  in- 
stead of  being  successive,  it  is  evident  that  the.  auricles  could  not  have 
emptied  themselves  into  the  ventricles.  The  alternate  action  is  more- 
over absolutely  necessary,  as  the  heart,  as  well  as  the  other  organs, 
is  unable  to  keep  up  a  perpetual  action;  the  principle  of  its  motion, 
which  is  soon  exhausted,  being  incapable  of  restoring  itself,  except  dur- 
ing rest.  But,  as  was  observed  at  the  beginning  of  this  work,  in  speak- 
ing of  the  vital  power  and  functions,  the  alternations  of  action  and  repose 
in  organs  which,  like  the  heart,  perform  functions  essential  to  life,  must 
be  extremely  short  in  their  duration,  and  at  very  close  intervals. 

The  cavities  of  the  heart,  however,  are  not  entirely  passive  during 
dilatation,  and  the  action  of  that  organ  does  not  wholly  depend  on  the 
excitement  of  the  blood  on  its  parietes,  since  the  heart  after  it  has  been 
torn  from  the  body  of  a  living  animal,  palpitates,  its  cavities  contract 
and  dilate,  though  quite  emptied  of  blood,  and  appear  agitated  by  alter- 


146 

nate  motions,  which  become  fainter  as  the  part  gets  cold.  If  you  attempt 
to  check  the  diastole  of  the  heart,  the  organ  resists  the  hand  which  com- 
presses it,  and  its  cavities  appear  endowed  with  a  power  which  Galen 
termed  pulsive;  in  virtue  of  which  they  dilate  to  receive  the  blood,  and 
not  because  they  receive  it.  In  that  respect,  the  heart  differs  essentially 
from  the  arteries,  whose  dilatation  is  occasioned  by  the  presence  of  the 
blood,  whatever  some  physiologists  may  have  said  to  the  contrary.  I 
have  repeated,  but  unsuccessfully,  the  famous  experiment  by  which  it  is 
attempted  to  be  proved,  that  these  vessels  have  the  power  of  moving  in- 
dependently of  the  presence  of  the  blood.  An  artery  tied  ar.d  emptied 
of  blood,  contracts  between  the  two  ligatures,  and  is  no  longer  seen  to 
move  in  alternate  contractions. 

LIII.  The  heart  manifestly  shortens  itself,  and  the  base  approaches 
towards  the  apex,  during  the  systole  or  contraction  of  the  ventricles.  If 
it  became  elongated,  as  some  anatomists  have  thought,  the  tricuspid  and 
miral  valves  would  ie  incapable  of  fulfilling  the  functions  to  which  they 
are  destined,  since  the  columnae  earner,  whose  tendons  are  inserted  in 
the  edges  of  these  valves,  would  keep  them  applied  to  the  parietes  of  the 
ventricles.  The  pulsations  which  are  felt,  in  the  interval  between  the 
cartilages  of  the  fifth  and  sixth  true  ribs,  are  occasioned  by  the  apex  of 
the  heart  which  strikes  against  the  parietes  of  the  chest.  In  the  expla- 
nation of  this  phenomenon,  it  is  not  necessary  to  admit  the  elongation  of 
the  heart  during  its  systole;  it  is  sufficient  to  consider,  that  the  base  of 
the  heart,  in  which  the  auricles  are  situated,  rests  against  the  vertebral 
column;  that  these  two  cavities,  by  dilating  at  the  same  time,  and  by  their 
inability  to  move  the  vertebrae,  before  which  they  are  situated,  displace 
the  heart,  and  thrust  it  downwards  and  forwards.  This  motion  depends, 
likewise,  on  the  effort  which  the  blood  sent  into  the  aorta  makes,  to 
bring  to  a  straight  line,  the  curvature  of  that  artery,  which  re-acts  and 
carries  downwards  and  forwards  the  whole  mass  of  the  heart,  as  it  were, 
suspended  to  it. 

The  quantity  of  blood  which  each  contraction  of  the  ventricles  sends 
into  the  aorta  and  pulmonary  artery,  most  probably,  does  not  exceed  two 
ounces  in  each  of  these  vessels.  The  force  with  which  the  heart  acts  on 
the  blood  which  it  sends  into  them,  is  but  imperfectly  known,  however 
numerous  the  calculations  by  which  it  has  been  endeavoured  to  solve 
this  physiological  problem.  In  fact,  from  Keil,  who  estimates  at  a  few 
ounces  only,  the  force  of  the  heart,  to  Borelli,  who  makes  it  amount  to 
one  hundred  and  eighty  thousand  pounds,  we  have  the  calculation  of  Mi- 
chelot,  Jurine,  Robinson,  Morgan,  Hales,  Sauvages,  Cheselden,  Sec.;  but 
as  Vicq-d'Azyr  observes,  not  one  of  these  calculations  is  without  some 
error,  either  anatomical  or  arithmetical:  hence  we  may  conclude  with 
Haller,  that  the  force  of  the  heart  is  great,  but  that  it  is,  perhaps,  im- 
possible to  estimate  it  with  mathematical  precision.  If  we  open  the 
chest  of  a  living  animal,  and  make  a  puncture  in  his  heart,  and  introduce 
a  finger  into  the  wound,  a  considerable  pressure  is  felt,  during  the  con- 
traction of  the  ventricles*. 


*  The  difficulty  of  determining  the  exact  degree  of  power  exerted  by  the  heart,  is 
strikingly  illustrated  by  the  total  disagreement  in  the  estimates  of  different  writers. 
Before  we  engage  in  an}  calculations  respecting  the  matter,  the  following  data  should 
be  clearly  established. 

1.  The  quantity  of  blood  expelled  from  each  ventricle  at  every  contraction* 


147 

Those  who  admit,  to  its  full  extent,  Harvey's  opinion  on  the  circula- 
tion of  the  blood,  and  who  think  with  him,  that  the  heart  is  the  sole  agent 
of  the  circulation,  overrate  the  power  of  that  organ,  so  as  to  proportion 
it  to  the  extent  of  the  course  which  the  blood  is  to  take,  and  to  the  num- 
ber of  the  obstacles  which  it  is  to  meet  in  its  way.  But,  as  I  am  about 
to  state,  the  blood-vessels  should  not  be  considered  as  inert  tubes,  in 
which  the  blood  flows  from  the  mere  impulse  which  it  has  received  from 
the  heart. 

LIV.  Of  the  action  of  the  arteries.  There  is  no  part  of  the  body  to  which 
the  .heart  does  not  send  blood  by  the  arteries,  for,  it  is  impossible  to 
make  a  puncture,  with  the  finest  netdle,  into  any  of  our  organs,  without 
wounding  several  of  these  vessels,  and  causing  an  effusion  of  blood.  The 
aortic  arterial  system  may  be  compared  to  a  tree,  whose  trunk,  repre- 
sented by  the  aorta,  having  its  root  in  the  left  ventricle  of  the  heart,  ex- 
tends afar  its  branches,  and  throws  out,  on  every  side,  its  numerous  ra- 
mifications. The  siz3  of  the  arteries  decreases,  the  farther  they  are  from 
the  trunk  by  which  they  are  given  off.  Their  form,  however,  is  not  that 
ot  a  cone,  they  are  rather  cylinders  arising  from  one  another,  and  de- 
creasing successively  in  size.  As  the  branches  given  off  by  a  trunk,  taken 
collectively,  have  a  greater  diameter  than  that  of  the  trunk  itself,  the  ca- 
pacity of  the  arterial  system  increases  with  the  distance  from  the  heart, 
hence  it  follows,  that  as  the  blood  is  continually  flowing  from  a  straighter 
to  a  wider  channel,  its  course  must  slacken.  The  direction  of  the  arte- 


2.  The  degree  of  velocity  with  which  it  is  expelled. 

3.  The  amount  of  resistence  which  each  ventricle  lias  to  overcome,  before  it  can 
propel  the  blood  into  its  corresponding  arteries. 

4.  The  effects  of  the  action  of"  the  heart  on  the  blood. 

But  these  are  points  which  seem  likely  never  to  be  ascertained  with  any  sort  of  pre- 
cision, and  of  course  Aur  computations  must  continue  as  heretofore,  vague  and  conjec- 
tural. All  we  know  with  certainty  on  the  subject  is,  that  the  heart  is  a  muscle  of  great 
strength,  as  is  evinced  by  the  phenomena  of  the  circulation,  and  further,  by  the  fact 
that,  if  the  heart  of  a  living  animal  be  grasped,  no  effort  of  the  hand  will  repress  its 
action. 

An  inquiry  far  more  interesting  here  presents  itself.  Why,  as  has  been  frequently 
asked,  does  not  the  heart  become  exhausted,  like  other  muscles,  by  exertion  ? 

Three  answers  to  this  intricate  question  have  been  attempted,  no  one  of  which,  how- 
ever, is  at  all  satisfactory. 

1.  By  Willis  it  is  maintained,  that  the  voluntary  muscles  derive  their  nerves  from  the 
cerebrum,  while  the  cerebellum  supplies  the  heart  and  other  involuntary  muscles ;  and 
hence  he  infers  that  the  one  set  is  thereby  fitted  for  temporary,  and  the  other  for  per- 
manent, and  uninterrupted  action. 

Admitting  the  statement  to  be  anatomically  correct,  we  do  not  perceive  that  it  leads 
to  any  such  conclusion.  But  it  is  not  so.  There  are  many  exceptions  to  this  alleged  dis- 
tribution of  the  nerves. 

2.  By  Stahl,  it  is  imputed  altogether  to  the  intelligence  of  his  anima  medica,  a  guar- 
dian power,  that  foreseeing  the  danger  to  which  the  system  would  be  exposed  by  any 
remission  in  the  action  of  the  heart,  ordains  it  otherwise.     This  is  all  hypothesis,  and 
of  the  most  wretched  kind  too ;  by  the  adoption  of  which  we  only  cut  the  knot  that 
perplexed  us  to  untie. 

3.  By  Haller  it  is  accounted  for  on  the  supposition  of  a  larger  share  of  irritability  be- 
ing possessed  by  the  heart.     It  is  to  be  recollected,  that  he  judged  of  the  degree  of 
this  property  by  the  duration  of  the  contractile  power  in  a  part,  after  the  death  of  the 
animal.     Taking  this  as  a  just  criterion,  it  will  appear  from  the  experiments  of  Fowler, 
that  in  cold-blooded  animals,  at  least,  the  voluntary  museles  retain  their  irritability  longer 
than  the  heart  itself.     The  difference,  indeed,  in  this  respect,  in  any  class  of  animals, 
is  so  slight,  that  other  objections  aside,  the  hypothesis  could  not  be  entertained.— 
Chapman. 


148 

ries  is  often  tortuous,  and  it  is  observed,  that  the  arteries  which  are  sent 
to  hollow  viscera,  as  the  stomach,  the  uterus,  and  the  bladder,  or  other 
parts  capable  of  contracting,  of  stretching,  and  of  changing  their  dimen- 
sions every  moment,  as  the  lips,  are  much  the  most  curved,  no  doubt, 
that  they  may  by  unfolding,  give  way  to  the  extension  of  the  tissues  into 
which  they  are  distributed.  Lastly,  the  arteries  arise  from  one  another, 
and  form  with  the  trunk  or  branch  from  which  they  are  given  off,  an 
angle  varying  in  size,  but  which  is  always  obtuse,  and  more  or  less  acute 
towards  the  branch. 

As  the  arteries  recede  from  their  origin,  they  communicate  together, 
and  these  anastomoses  form  arches,  two  branches  bending  towards  each 
other,  and  joining  at  their  extremities,  as  we  see  in  the  vessels  of  the 
mesentery;  sometimes  two  parallel  branches  meet  at  an  acute  angle, 
and  unite  into  one  trunk,  thus  the  two  vertebrals  join  to  form  the  basilar 
artery:  some  communicate  by  transverse  branches,  which  pass  from  the 
one  to  the  other,  as  is  seen  within  the  skull. 

In  the  anastomoses  of  the  first  kind,  the  columns  of  blood  Sowing,  in 
contrary  directions,  along  the  two  branches,  meet  at  the  point  of  union? 
and  mutually  repel  each  other,  their  particles  mingle,  and  lose  much  of 
their  motion  in  that  reciprocal  shock.  The  blood  then  follows  a  middle 
direction,  and  enters  the  branches  which  arise  from  the  convexity  of 
these  anastomotic  arches. 

When  two  branches  unite  to  produce  a  new  artery,  of  a  greater  calibre 
than  each  taken  separately,  but  not  so  large  as  both  together,  the  motion 
of  the  blood  becomes  accelerated,  because  it  passes  from  a  more  capacious 
into  a  straighter  channel,  and  the  forces  which  determined  its  progression, 
are  concentrated  into  one.  Lastly,  the  transverse  anastomoses  are  well 
calculated  to  promote  the  passage  of  the  blood  from  the  one  branch  into 
the  other,  and  to  prevent  congestion  in  the  parts. 

LV.  The  arteries  are  imbedded  in  a  certain  quantity  of  cellular  tissue, 
are  almost  universally  accompanied  by  corresponding  veins,  by  lympha- 
tics and  nerves,  and  their  coats  are  thicker  in  proportion  as  their  calibre 
is  smaller.  The  experiments  of  Clifton  Wintringham  prove,  that  the 
parietes  are  stronger  in  the  small  than  in  the  large  arteries,  hence  it  is 
observed,  that  aneurisms  are  much  less  frequent  in  the  former.  Their 
parietes  have  sufficient  firmness  not  to  collapse,  when  the  tube  of  the  ar- 
tery is  empty.  They  are  formed  of  three  coats;  the  external  or  cellular 
admits  of  considerable  extension,  and  appears  to  be  formed  by  the  con- 
densation of  the  lamina  of  the  cellular  tissue,  which  surrounds  the  arte- 
ry, and  unites  it  to  the  neighbouring  parts.  The  second  coat  is  thicker 
and  firmer,  of  a  yellow  colour,  and  fibrous,  and  is  by  some  considered  as 
muscular*  and  contractile,  while  other  physiologists  merely  allow  it  to 
possess  a  considerable  degree  of  elasticity.  The  longitudinal  fibres,  ad- 
mitted by  some  authors  in  the  texture  of  this  second  coat  cannot  be  dis- 
tinguished, and  their  existence  is  not  necessary  to  account  for  the  longi- 
tudinal retraction  of  arteries.  In  fact,  this  retraction  might  depend  on 


*  If  in  man  and  the  greater  number  of  animals,  the  yellow  fibres  which  form  this 
coat,  differ  greatly  from  muscular  fibres,  they  in  the  elephant  resemble  that  texture 
very  completely,  as  I  had  an  opportunity  of  observing1,  when  I  witnessed  the  dissection 
of  the  elephant  that  died  in  the  year  1802,  at  the  Museum  of  Natural  History.  Let  men 
of  judgment  decide  whether  the  analogy  is  sufficient  to  warrant  our  admitting,  in  the 
arteries  of  the  human  body,  the  existence  of  muscular  fibres.— Author's  Nate. 


149 

elasticity,  it  might  likewise  be  occasioned  by  the  contraction  of  fibres 
not  absolutely  circular  nor  longitudinal,  but  spiral  and  imperfectly  sur- 
rounding the  vessel,  and  crossing  each  other  in  various  directions.  This 
yellow  coat,  thicker  in  proportion  in  the  smaller  arterial  twigs,  than  in 
the  larger  branches,  and  thicker  in  these  than  in  the  trunks,  is  dry,  hard, 
not  capable  of  much  extension,  and  is  ruptured  by  an  effort  to  which  the 
external  coat  yields  by  stretching.  Lastly,  a  third,  thin,  and  epidermoid 
coat  lines  the  inside  of  these  vessels,  and  seems  less  adapted  to  give 
strength  to  the  parietes  of  the  arteries,  than  to  facilitate  the  flow  of  the 
blood,  by  presenting  to  it  a  smooth,  even,  and  slippery  surface,  continu- 
ally moistened  by  a  serous  exudation,  from  the  minute  arteries,  or  vasa 
vasorum,  which  are  distributed  between  these  coats*. 

Besides  these  three  coats,  the  great  arteries  receive  a  fourth  from  the 
membranes  lining  the  great  cavities;  thus,  the  pericardium  and  the 
pleura  in  the  chest,  the  peritoneum  in  the  abdomen,  furnish  to  the  dif- 
ferent parts  of  the  aorta,  an  adventitious  coat  which  does  not  completely 
surround  the  vessel. 

Of  the  three  coats  which  form  the  parietes  of  the  arteries,  the  fibrous, 
though  thicker  than  the  other  two,  offers,  however,  the  least  resistance. 
If  you  take  the  carotid  artery,  which  for  a  considerable  space,  does  not 
send  off  any  branches,  and  forcibly  inject  into  it  a  fluid,  the  internal  and 
middle  coat  will  be  torn,  before  dilatation  has  increased,  by  one-half,  the 
calibre  of  the  vessel.  The  external  coat  resists  the  cause  of  rupture, 
by  dilating,  and  forms  a  tumour,  and  it  is  only  by  applying  a  conside- 
rable force,  that  it  can  be  ruptured.  The  experiment  is  attended  with 
the  same  success,  if  performed  with  air  or  any  other  gas.  In  aneu- 
rism, the  internal  and  fibrous  coats  of  the  arteries,  but  more  particularly 
the  fibrous,  are  ruptured  at  an  early  stage  of  the  disease,  which  at  that 
period  increases  suddenly,  in  a  very  rapid  manner,  and  on  opening  the 
tumour,  it  is  observed,  that  the  sac  is  entirely  formed  by  the  dilated  cel- 
lular coat.  Take  an  artery  of  a  certain  calibre,  for  example  the  carotid 
or  humeral,  apply  a  ligature  around  it,  and  tighten  it  with  some  degree  of 
force.  Dissect  and  take  out  the  vessel,  then  cut  the  thread,  and  examine 
the  place  to  which  it  was  applied,  you  will  observe,  that  the  parietes  of 
the  artery  are  in  that  part  thinner,  and  formed  merely  by  the  cellular 
coat  which  alone  has  withstood  the  constriction.  Take  hold  of  the  two 
ends  of  an  insulated  arterial  tubt,  and  stretch  it,  then  examine  its  inner 
coat,  and  you  will  find  it  torn  and  cracked  in  several  places,  and  the  pa- 
rietes of  the  artery  evidently  weakened!- 

LVI.  This  want  of  extensibility  in  the  coats  of  arteries,  is  the  princi- 
pal cause  of  aneurism ;  hence  the  popliteal  artery  is  so  liable  to  that  af- 
fection, from  its  situation  behind  the  keee,  whose  extension  is  limited, 
merely  by  the  resistance  of  the  posterior  tendons  and  ligaments:  this  ar- 
tery is  affected  by  the  jar  which  takes  place  through  all  the  soft  parts, 
when  the  leg  is  violently  extended;  and  being  less  extensible  than  the 
other  parts,  its  inner  coat  is  ruptured,  or  at  least  weakened,  so  as  to  oc- 
casion an  aneurism,  always  rapid  in  its  progress.  Of  ten  popliteal  aneu- 
risms which  I  have  seen  in  different  hospitals,  eight  were  ascribed  to  a 


*  See  APPENDIX,  Note  R,  for  remarks  on  the  structure  and  action  of  the  arteries. 
7  For  a  full  relation  of  the  effects  of  ligatures  on  arteries,  see  «  Jones  on  Hemorr- 
hage."— Godman, 


150 

violent  extension  of  the  ham.  In  looking  over  the  cases  that  have  been 
recorded,  it  will  be  seen,  that  a  considerable  number  of  aneurisms  of  the 
aorta,  have  been  occasioned  by  too  forcible  arid  too  sudden  an  extension  of 
the  trunk  in  raising  a  heavy  burthen. 

From  the  dryness,  the  frailly  of  the  yellow  or  fibrous  coat  of  arteries, 
the  application  of  ligatures  to  these  vessels  is  attended  with  a  speedy  la- 
ceration of  their  tissue;  a  moderate  degree  of  compression  is  sufficient 
to  rupture  that  coat,  the  external  and  internal  remaining,  at  the  same 
time,  uninjured,  provided  the  constriction  be  not  excessive.  Why  is  the 
arterial  tissue,  almost  the  only  one  on  which  ligatures  require  to  be  ap- 
plied, the  least  fitted  of  all  the  organic  tissues  to  bear  them  ?  This  incon- 
venience attending  «the  ligature  of  arteries,  led  Pouteau  to  prefer  tying 
arteries  so  as  to  include  the  surrounding  soft  parts  within  the  ligature, 
though  this  process  is,  in  other  respects,  less  eligible.  The  objections 
will  be  obviated,  by  employing  flat  ligatures,  which,  by  acting  on  a  great- 
er surface  of  the  artery,  are  less  likely  to  divide  the  coats  of  the  vessel, 
which  will  become  obliterated  at  the  spot  to  which  the  ligature  is  applied, 
the  more  rapidly  as  the  patient  is  younger  and  stronger. 

I  once  saw,  in  a  man  whose  thigh  was  amputated,  on  account  of  caries 
of  the  knee  joint  combined  with  a  scorbutic  affection,  hemorrhage  attend 
the  fall  of  the  ligatures,  which  did  not  come  away  till  nineteen  days  after 
the  operation;  as  if  the  fibrous  coat  of  these  arteries,  partaking  in  the 
debility  of  the  muscular  organs,  had  not  preserved  a  sufficient  degree  of 
contractile  power  to  close  the  cavity  of  the  vessel. 

LVJI.  The  contractile  power  of  the  arteries  is  in  their  middle  coat, 
it  is  greater,  as  this  coat  is  thicker  in  proportion  to  the  calibre  of  the  ar- 
tery. Hence,  as  Hunter  observes,  in  his  work  on  the  blood  and  inflam- 
mation, the  larger  arteries  are  endowed  with  elasticity,  merely,  while 
on  the  other  hand,  contractility  is  very  apparent  in  those  of  a  smaller  ca- 
libre, and  is  found  complete  in  the  capillary  vessels  *  ;  hence,  in  the  trunks 
near  the  heart,  the  progression  of  the  blood  is  effected,  chiefly  by  the 
impulse  which  it  receives  from  the  heart,  and  as  Lazarus  Riviere  ob- 
served, the  circulation  of  the  blood  in  the  large  vessels,  is  more  an  hy- 
draulic than  a  v  tal  phenomenon.  The  action  of  the  main  arterial  trunks, 
near  the  heart,  has  so  little  influence  on  the  motion  of  the  blood  sent  in- 
to them  by  that  organ,  that  the  aorta  is  frequently  ossified,  without  af- 
fecting the  circulation.  The  aorta  is  n&urally  bony  in  the  sturgeon.  J. 
L.  Petit,  in  the  case  of  a  bookseller,  whose  leg  he  had  taken  off,  found  all 
the  arteries  of  a  certain  calibre  in  a  state  of  ossification;  they  were  indu- 
rated, and  of  course,  incapable  of  acting,  in  the  slightest  degree,  on  the 
column  of  blood  which  flowed  along  them.  All  these  facts  seem  conclu- 
sive arguments  in  favour  of  those  physiologists,  who  explain,  on  theprin- 


*  This  is  not  altogether  correct.  Every  portion  of  the  arterial  system  is  unquesti- 
onably possessed  of  the  property  of  contractility.  In  the  larger  vessels,  muscular  fibres 
are  even  demonstrated  to  the  eye.  Besides,  mere  elasticity  will  not  explain  many  of 
the  phenomena  of  arterial  action.  Contrary  to  the  doctrine  of  Mr.  Hunter,  it  was  mam- 
tained  by  Baron  Haller,  and  indeed  by  almost  all  the  coteroporary  physiologists,  that 
contractility  belongs  exclusively  to  the  large  and  middle  sized  arteries.  In  this,  how- 
ever, they  were  deceived. 

It  is  now  well  ascertained,  that  muscularity  increases  exactly  as  the  vessel  recedes 
from  the  heart,  the  capillaries  having  it  in  the  greatest  degree.  As  far  as  I  know,  this 
opinion  was  originally  taught  by  Cullen,  and  afterwards  fully  confirmed  by  the  experi- 
ments of  Hunter. —Chapman. 


151 

dple  of  elasticity,  the  contraction  of  arteries.  But  however  correct  this 
explanation  may  be,  with  regard  to  the  vessels  near  the  heart,  it  does  not 
apply  to  the  capillaries;  the  influence  of  that  organ  does  not  operate  on 
these  vessels.  One  may  easily  conceive,  that  the  column  of  blood  which 
by  the  impulse  it  has  received,  in  the  first  instance,  has  been  sent  along 
the  whole  length  of  tubes  whose  sides  are  ossified,  inflexible,  and  conse- 
quently inert,  on  reaching  the  extremity  of  these  canals,  is,  in  a  manner, 
again  taken  up  by  the  vital  power  residing  in  the  capillary  vessels,  and 
circulates  from  the  influence  of  the  action  belonging  to  these  vessels*. 
Besides,  elasticity,  however  considerable,  merely  restores  those  tissues 
that  have  been  stretched,  to  the  condition  in  which  they  were  before  ex- 
tension. Elasticity  is  a  kind  of  re-action,  proportionate  or  relative  to  the 
action  which  precedes  it.  Why  do  arteries  in  the  living  body  contract, 
to  such  a  degree,  that  when  empty,  their  canal  becomes  obliterated, 
while  in  the  dead  body,  however  perfect  the  depletion  of  the  arterial 
system  may  have  been,  the  cavity  of  the  arteries  remains  perfectly  open. 
Several  physiologists,  however,  and  those  among-  the  most  modern,  con- 
sider elasticity  as  the  principal  cause  of  the  progression  of  the  blood 
along  the  arteriesf. 

As  the  distance  from  the  centre  increases  the  circulation  slackens,  from 
several  causes,  and  the  blood  could  not  reach  all  the  parts  of  the  body,  if 
the  arteries,  whose  vitality  increases  with  their  distance  from  the  heart, 
and  as  they  become  smaller,  did  not  propel  it  to  all  the  organs.  The 
causes  which  retard  the  circulation  of  the  arterial  blood,  are,  the  increased 
dimensions  of  the  space  in  which  it  is  contained  ; — the  resistance  from  the 
curves  of  the  vessels; — the  friction  which  it  undergoes,  and  which  in- 


*  I  have  dissected  the  brain  of  a  female,  (apparently1  between  fifty  and  sixty  years 
old,)  in  which  the  arteries  were  rigidly  ossified  from  their  great  trunks,  down  to 
branches  not  larger  than  a  tine  knitting1  needle.  In  the  left  thalamus  opticus  there  was 
a  brownish  discolouration,  which  seemed  to  m-.irk  the  spot  where  blood  had  been  ef- 
fused some  time  before  death. —  Godman. 

-j-  It  has  always  been  a  matter  of  controversy  among  physiologists,  whether  the  blood 
is  propelled  by  the  heart  only,  or  whether  the"  arteries  co-operate  to  the  same  end.  It 
is  well  known  that  the  illustrious  Harvey,  the  discoverer  of  the  circulation,  was  of  the 
former  opinion,  and  that  he  has  since  been  supported  by  many  followers.  We  admit, 
at  once,  that  the  heart  is  the  chief  organ  concerned,  but  it  seems  to  us  equally  true  that 
the  arteries  also  exercise  a  considerable  agency,  most  commonly  as  auxiliary  to  the  heart, 
yet  sometimes  to  a  certain  extent  independently  of  that  organ.  These  two  positions 
are  demonstrable,  both  by  experiment  and  fact. 

1.  It  has  been  proved  that  the  muscular  power  is  inherent  in  all  the  arteries  of  the 
body,  in  the  large  and  small,  in  the  main  trunks  as  well  as  in  the  capillary  extremities. 

2.  That  the  arteries  contract   with  considerable  force,  the  natural  and  unavoida- 
ble effect  of  which  must  be,  the  propulsion  of  the  blood,  and  the  quickening  of  the 
circulation. 

3.  That  the  circulation  has  been  maintained  in  the  foetus,  though  utterly  destitute  of 
a  heart.     Cases  of  this  description  are  recorded  in  sufficient  number,  to  put  the  fact  be- 
yond a  doubt.     It  may,  however,  be  alleged,  that  in  these  instances,  as  very  often  hap- 
pens in  the  history  of  the  animal  economy,  the  want  of  one  organ  is  supp  ied  by  the  as- 
sumption of  new,  or  increased  powers  by  some  other.     We  do  not  perceive  much  force 
in  this  objection,  but  as  it  might  be  raised,  we  will  appeal  to  other  facts  of  a  less  dis- 
putable nature,  such  as  are  afforded  by  the  phenomena  of  local  inflammation,  active 
haemorrhages,  blushing,  hectic  suffusion,  and  many  more  which  it  would  be  easy  to 
enumerate.     Enough,  however,  have  been  mentioned,  to  show  that  the  circulation  may 
be  increased  in  a  particular  part  without  its  being  generally  affected,  and  consequently 
that  the  heart  is  not  the  only  power  which  propels  the  blood,  but  that  this  force  also 
resides,  in  a  limited  degree,  in  the  arteries. —  Chapman. 


152 

creases,  as,  at  a  distance  from  the  heart,  the  canals  along'  which  it  circtt* 
lates,  increase  in  number;  and  lastly,  the  deviations  which  the  blood 
meets  with  in  its  course,  from  the  trunks  into  the  branches  which, 
coming  off  sometimes,  almost  at  right  angles,  divert  it  from  its  original 
direction. 

Several  physiologists  have  called  in  question  this  progressive  slacken- 
ing of  the  flow  of  arterial  blood,  and  several  among  them,  who  reject  en- 
tirely the  application  of  the  physical  sciences  to  that  of  the  animal  econo- 
my, have,  nevertheless,  supported  their  opinion  by  a  fact  taken  from  hy- 
draulics. To  give  any  certainty  to  these  calculations,  respecting  the 
impediments  to  the  circulation  of  the  blood  in  the  arteries,  it  would,  they 
say,  be  necessary,  that  the  arteries  should  be  empty  at  the  instant  when 
they  receive  the  jet  of  blood  sent  into  them  by  the  contraction  of  the 
ventricles.  This,  however,  is  not  the  case  ;  the  arteries  are  always  full, 
the  blood  flows  along  all  of  them  with  the  same  degree  of  velocity.  This 
system  of  vessels  may  be  compared  to  a  syringe,  from  which  a  number  of 
straight  and  tortuous  tubes  should  arise;  each  of  these  would  throw  out 
the  fluid  with  an  equal  degree  of  velocity,  on  applying  pressure  to  the 
piston. 

In  refuting  this  doctrine,  I  must  take  notice  of  the  manifest  contradic- 
tion of  pretending  to  exclude,  absolutely,  all  application  of  the  principles 
of  mechanics  tp  physiology,  and  the  complete  application  of  these  princi- 
ples to  the  phenomena  of  the  animal  economy.  This  contradiction,  how- 
ever, is  not  more  surprising  than  that  of  authors  who  exclaim  against  the 
abuse  of  modern  nomenclators,  and  who,  nevertheless,  eagerly  embrace 
every  opportunity  of  adding  to  it,  by  assigning  new  names  to  such  parts 
as  may  have  escaped  the  attention  of  the  new  nomenclators.  What  re- 
semblance is  there,  between  a  forcing  pump,  whose  sides  are  unyielding, 
as  well  as  those  of  the  tubes  which  might  arise  from  it,  and  the  aorta  which 
dilates  every  time  the  blood  is  sent  into  it;  and  again,  what  resemblance 
is  there,  between  tubes  which  decrease  towards  their  open  extremities, 
\vhilethespacecontained  in  the  arterial  tube  constantly  enlarges,  from 
the  innumerable  divisions  of  the  vessels.  Since  it  is  admitted,  that  the 
coarse  of  the  blood  is  slower  in  the  capillary  vessels,  must  not  this  re- 
sistance, opposed  to  the  blood  which  fills  the  series  of  vessels  from  the 
capillaries  to  the  heart,  be  felt  more  at  a  greater  distance  from  that  organ, 
&c.?  Without  this  progressive  increase  of  resistance,  as  the  arterial 
blood  is  at  a  greater  distance  from  the  heart,  this  fluid  would  flow  along 
the  arteries,  as  it  does  along  the  veins  without  any  pulsations  ;  for,  this 
resistance,  which  causes  the  lateral  effort  of  dilatation  effected  by  the 
blood  on  the  parietes  of  the  arteries,  is  the  principal  cause  of  the  pulse, 
which  belongs  only  to  that  set  of  vessels.  A  very  remarkable  difference 
is  observable,  between  the  blood  which  is  sent  to  the  toes,  and  that  which 
goes  to  the  mammae,  as  I  have  several  times  noticed  in  removing  the  cu- 
rious bones  of  the  toes,  or  in  extirpating  cancerous  breasts :  the  small  ar- 
teries of  these  parts  are  nearly  of  the  same  size,  but  the  jet  of  blood  is 
much  more  rapid,  the  blood  is  sent  to  a  much  greater  distance,  when  one 
of  the  mammary  arteries  is  divided. 

The  re-action  of  the  arteries  on  the  blood  which  dilates  them,  depends 
not  only  on  the  great  elasticity  of  their  parietes,  but  likewise  on  the  con- 
tractility of  the  muscular  coat.  Elasticity  has  a  considerable  share  in  the 
action  of  the  larger  trunks,  while  contractility  is  almost  the  sole  agent, 
in  producing  the  action  of  the  minute  arteries.  If  a  finger  is  introduced 


153 

into  the  artery  of  a  living  animal,  its  parietes  compress  it  in  every  direc- 
tion ;  if  the  blood  is  prevented  from  flowing  in  it,  the  canal  becomes 
obliterated  by  the  adhesion  of  its  parietes*  and  the  vessel  is  converted 
into  a  ligamentous  cord,  such  as  that  formed  in  the  adult,  by  the  remains 
of  the  umbilical  arteries  and  veins.  This  contractility  which,  during 
life,  is  always  in  action,  keeps  the  arteries,  distended  by  the  blood  which 
fills  them,  of  a  smaller  calibre,  than  after  death.  In  performing  capital 
operations,  especially  in  the  amputation  of  limbs,  I  have  always  found  the 
arteries,  whether  filled  with  blood  or  empty,  much  smaller  than  I  should 
have  expected  from  their  appearance  in  the  dead  body. 

It  happens,  however,  sometimes,  that  the  quantity  of  blood  sent  to  an 
organ  increases,  in  consequence  of  some  cause  of  irritation;  the  calibre 
of  the  arteries  of  the  part,  then  becomes  remarkably  enlarged.  Thus, 
the  arteries  of  the  uterus,  which  are  very  small  in  its  unimpregnated 
state?  acquire,  towards  the  end  of  pregnancy,  a  calibre  equal  to  that  of 
the  radial  artery*,  the  small  arteries  which  are  sent  to  the  mammae,  are 
not  in  the  same  condition,  as  I  have  had  the  opportunity  of  ascertaining 
in  a  woman  who  had  been  sucking  a  child  for  two  months  before  her 
death;  they  retained  their  almost  capillary  minuteness,  which  would 
seem  to  prove,  that  the  lymphatics  are  alrme  cQnru?merl  in  bringing  to 
these  glands  the  materials  of  their  secretion.  The  mammary  arteries 
evidently  enlarged  in  an  open  cancer  of  the  breast;  in  cancer  of  the  pe- 
nis, the  blood-vessels  likewise  become  enlarged;  hence  in  removing  the 
penis  for  that  affection,  it  is  absolutely  necessary  to  secure  the  arteries 
with  ligatures,  a  precaution  which  need  not  be  attended  to  in  a  case  of 
gangrene.  Gangrene  is  attended  with  this  peculiarity,  that  the  arteries 
of  the  mortified  parts  contract,  so  as  to  become  obliterated,  when  their 
calibre  is  inconsiderable. 

As  the  arteries  are  the  canals  which  convey  to  all  our  organs  the  ma- 
terials of  growth  and  reparation,  they  are  larger,  in  proportion,  in  child- 
ren, in  whom  nutrition  is  more  active,  and  their  calibre  is  always  propor- 
tionate to  the  natural  or  morbid  developement  of  organs  :  hence  the  de- 
scending aorta  and  the  iliac  arteries  are  larger  in  women  than  in  men; 
hence  the  right  subclavian  artery,  which  conveys  blood  to  the  larger  and 
more  powerful  of  the  two  upper  extremities,  because  being  more  em  ployed, 
it  is  larger  than  the  left  subclavian.  But  the  effect  should  not  be  mistaken 
for  the  cause,  and  it  should  not  be  imagined,  that  the  right  upper  extre- 
mity owes  its  superiority  to  the  greater  calibre  of  its  artery.  In  the  new- 
born child,  this  vessel  is  not  larger  than  the  left  subclavin  :  but  the  right 
arm  being  more  frequently  employed,  the  distribution  of  the  fluids  takes 
place  more  favourably,  nutrition  is  carried  on  with  more  energy,  it  ac- 
quires more  bulk  and  strength,  and  therefore  the  right  subclavian  artery 
conveys  blood  to  it  by  a  wider  channel.  If  the  left  upper  extremity 
were  employed  in  the  same  manner,  and  if  the  right  were  kept  in  a  state 
of  inaction,  the  left  subclavian  would,  no  doubt,  exceed  the  right.  I  am 
warranted  by  two  facts  in  forming  this  conjecture.  lu  dissecting  the  bo- 
dies of  two  men  that  were  left-handed,  I  observed  in  the  left  subclavian 
arteries,  the  same  proportionate  enlargement  which  is  usually  met  with  in 
the  same  vessels  on  the  right  side. 


*  This  increase  of  size  in  the  arteries  of  the  gravid  uterus,  is  a  proper  growth  of  parts, 
not  an  accidental  dilatation* — Gadman. 

U 


154 

LVIII.  As  the  arteries  are  always  full  during  life,  and  as  the  blood 
flows  along  them  with  less  velocity,  the  greater  their  distance  from  the 
heart,  the  blood  which  the  contractions  of  the  left  ventricle  send  into  the 
aorta,  meeting  the  column  of  blood  already  in  that  vessel,  communicates 
to  it  the  impulse  which  it  has  received;  but  retarded  in  its  direct  progres- 
sion, by  the  resistance  of  that  column,  it  acts  against  the  parietes  of  the 
vessels,  arid  removes  them  to  a  greater  distance  from  their  axis.  This 
lateral  action  which  dilates  the  arteries,  depends,  therefore,  on  the  resist- 
ance of  the  parietes  of  these  cavities,  always  filled  with  blood,  to  that 
which  the  heart  sends  into  them.  This  dilatation,  which  is  more  consi- 
derable in  the  large  arteries  than  in  the  smaller  ones,  manifests  itself  by 
a  beat,  known  under  the  name  of  puke*.  The  experiments  of  Lamure 
would  lead  one  to  believe,  that  another  cause  of  this  phenomena  is  a 
slight  displacement  of  the  arteries,  every  time  they  dilate.  These  dis- 
placements are  most  easily  observed  at  their  curvatures,  and  where* they 
adhere  to  surrounding  parts,  by  a  loose  and  yielding  cellular  tissue. 

The  pulse  is  more  frequent  in  women,  in  children,  in  persons  of  small 
stature,  during  the  influence  of  the  passions,  and  under  violent  bodily  ex- 
ercise, than  in  an  adult  man,  of  high  stature,  and  of  a  calm,  physical,  and 
moral  nature.  At  an  early  period  of  life,  the  pulse  beats  as  often  as  a 
hundred  and  forty  times  in  a  minute.  But  as  the  child  gets  older,  the 
motion  of  the  circulation  slackens,  and  at  two  years  old,  the  pulse  beats 
only  a  hundred  times,  in  the  same  lapse  of  time.  At  the  age  of  puberty, 
the  beats  of  the  pulse  are  about  eighty  in  a  minute;  in  manhood,  seventy- 
five  ;  and  lastly,  in  old  men  of  sixty,  the  pulse  is  not  above  sixty.  It  is 
slower  in  the  inhabitants  of  cold,  than  in  those  of  warm  climates. 

Since  the  time  of  Galen,  the  pulse  has  furnished  physicians  with  one 
of  their  principal  sources  of  diagnosis.  The  force,  the  regularity,  the 
equality  of  its  pulsations,  opposed  to  their  weakness,  inequality,  irregu- 
larity, and  intermittence,  afford  the  means  of  judging  of  the  nature  and 
danger  of  a  disease,  of  the  power  of  nature  in  bringing  about  a  cure,  of 
the  organ  that  is  most  affected,  of  the  time  or  period  of  the  complaint, 
Sec.  No  one  has  been  more  successful  than  Bordeu,in  the  consideration 
of  the  pulse,  under  these  different  points  of  view.  Its  modifications  in- 
dicative of  the  periods  of  diseases,  establish,  according  to  that  celebrated 
physician,  as  may  be  seen  in  his  Recherches  sur  le  fiouls  par  rapfiort  aux 
crises,  the  pulse  of  crudity,  of  irritation,  and  of  concoction.  Certain  ge- 
neral characters  indicate,  whether  the  affection  is  situated  above  or  be- 
low the  diaphragm,  hence  the  distinction  of  superior  and  inferior  fiulse. 
Lastly,  peculiar  characters  denote  the  lesion  of  peculiar  organs;  which 
constitutes  the  nasal,  guttural,  pectoral,  stomachic,  hepatic,  intestinal, 
renal,  uterine,  Sec. 

Besides  these  sensible  beats,  which  constitute  the  phenomenon  of  the 
pulse  in  the  arteries,  there  is  an  inward  and  obscure  pulsatory  motion,  by 
which  all  the  parts  of  the  body  are  agitated,  every  time  that  the  ventri- 
cles of  the  heart  contract.  There  is  a  kind  of  antagonism  between  the 
heart  and  the  other  organs,  they  yield  to  the  impulse  which  it  gives  to 
the  blood,  dilate  on  receiving  this  fluid,  and  collapse  when  the  effort  of 
contraction  is  over.  Every  part  vibrates,  trembles,  and  palpitates  within 


*  See  APPENDIX,  Note  S,  for  a  different  explanation  of  this  phenomenon  from  that 
given  by  Richerand. 


155 

the  body,  the  motions  of  the  heart  shake  its  whole  mass,  and  these  qui- 
verings, which  may  be  observed  externally,  are  most  manifest  when  the 
circulation  is  carried  on  with  rapidity  and  force.  In  some  head-jches, 
the  internal  carotid  arteries  pulsate  with  such  violence,  tJutt  nut  only  the 
ear  is  sensible  to  the  noise  made  by  the  column  of  blood  striking-  against 
the  curvature  of  the  osseous  canal,  but  the  head  is  evidently  moved  and 
raised,  as  it  were,  at  each  pulsation.  If  you  look  at  your  hand  or  foot, 
when  the  upper  or  lower  extremity  is  quiescent  and  pendulous,  you  will 
observe  in  it,  a  slight  motion  corresponding  to  the  beats  of  the  heart. 
This  motion  increases,  and  even  makes  the  hand  shake,  when,  from  the 
influence  of  the  passions,  or  from  violent  exercise,  the  circulation  is  ac- 
celerated; in  every  violent  emotion,  we  feel,  within  ourselves,  the  effort 
by  which  the  blood,  at  each  beat  of  the  pulse,  penetrates  into  our  organs, 
and  fills  every  tissue.  And  it  is,  in  a  great  measure,  from  this  inward 
tact,  that  we  are  conscious  of  existence.  A  consciousness  the  more  lively 
and  distinct,  as  the  effect  of  which  we  are  speaking  is  more  marked.  It 
is,  likewise,  from  observing  this  phenomenon,  that  several  physiologists 
have  been  led  to  conceive  the  idea  of  a  double  motion,  which  dilates  or 
condenses,  which  contracts  or  expands,  alternately,  all  organs  endowed 
with  life  ;  they  have  observed,  that  dilatation  prevails  in  youth,  in  inflam- 
mation and  erection,  conditions  of  which  all  parts  are  capable,  according 
to  their  difference  of  structure. 

LIX.  At  the  moment  when  the  left  ventricle  contracts,  to  send  the 
blood  into  the  aorta,  the  sigmoid  valves  of  that  artery  rise,  and  apply 
themselves  to  its  parietes,  without,  nevertheless,  closing  the  orifices  of 
the  coronary  arteries,  which  lie  above  the  loose  edges  of  the  valves;  so 
that  the  blood  is  received  into  these  vessels,  at  the  same  time  as  into  the 
others.  When  the  contraction  of  the  ventricle  is  over,  the  aorta  acts  on 
the  blood  which  it  contains,  and  would  send  it  back  into  the  ventricle,  if 
the  valves,  by  suddenly  descending,  did  not  present  an  insuperable  obsta- 
cle to  the  return  of  blood,  and  did  not  yield  a  point  of  resistance  to  the 
action  of  the  whole  arterial  system  ;  only  the  small  quantity  of  blood  be- 
low the  valves,  at  the  moment  of  their  descending,  flows  back  towards 
the  heart,  and  returns  into  the  ventricle, 

Though  the  rate  at  which  the  blood  flows  along  the  aorta,  has  been 
estimated  at  only  about  eight  inches  in  a  second,  a  pulsation  is  felt  in  all 
the  arteries  of  a  certain  calibre,  at  the  instant  the  ventricles  are  contract- 
ing. The  reason  that  the  pulsations  of  the  heart  appear  to  take  place,  at 
the  same  time  as  those  of  the  arteries,  is,  that  the  columns  of  blood,  in 
these  vessels,  receive  an  impulse  from  that  which  is  issuing  from  the*  ven- 
tricles, and  this  concussion  is  felt  in  an  instant  of  time,  too  short  to  be' 
measured,  such  as  that  which  is  felt  by  the  hand  applied  to  the  end  of  a 
piece  of  timber  struck,  at  the  other  end,  with  a  hammer.  The  blood 
which  fills  the  main  trunk,  supplies  to  each  of  the  branches  which  arise 
from  it,  columns  proportionate  to  their  calibre.  This  division  of  the 
principal  column  is  effected  by  a  kind  of  projection  at  the  mouth  of  each 
artery.  These  internal  projections  detach  from  the  main  stream,  the 
lesser  ones,  and  these  flow  the  more  readily  into  the  branches,  according 
as  these  arise  from  the  trunk,  at  a  more  acute  angle,  as  the  projection  is 
more  prominent,  and  the  deviation  of  the  fluid  less  considerable.  If  the 
branches  are  given  off,  at  an  almost  right  angle,  the  orifices  of  the  arte- 
ries scarcely  project  at  all,  and  nothing  but  the  effort  of  lateral  pressure; 
determines  the  flow  of  the  blood  into  them. 


156 

The  flow  of  the  blood  into  the  arteries  which  are  distributed  to  mus- 
cles, is  not  interrupted,  when  these  muscles  contract,  for,  whenever  arte- 
ries, of  a  certain  calibre,  penetrate  into  muscles,  they  are  surrounded  by 
a  tendinous  ring1,  which,  during  the  contraction  of  the  muscle,  becomes 
enlarged,  from  the  extension  in  every  direction,  effected  by  the  fibres 
which  are  attached  to  it,  around  its  circumference.  The  existence  of 
this  truly  admirable  conformation,  may  be  readily  ascertained,  by  observ- 
ing the  aorta,  in  its  passage  through  the  crura  of  the  diaphragm;  the 
perforating  arteries  of  the  thigh,  where  they  enter  at  the  back  part  of  the 
limb  into  the  adductor  muscles,  the  popliteal,  as  it  passes  through  the 
upper  extremity  of  the  soleus  muscle. 

LX.  Of  the  capillary  -vessels.  The  arteries,  after  dividing  into  branches, 
these  branches  into  lesser  ones,  and  these  into  progressively  smaller 
ramifications,  terminate  in  the  tissue  of  our  organs,  by  becoming  conti- 
nuous with  the  veins.  The  venous  system  arises,  therefore,  from  the  ar- 
terial system,  the  origin  of  the  veins  being  merely  the  more  minute  ex- 
tremities of  the  arteries,  which  becoming  capillary  from  the  great  number 
of  divisions*  they  have  undergone,  bend  in  an  opposite  direction,  and 
become  altered  in  their  structure. 

These  minute  capillary  arteries  form  with  the  minute  veins,  with  which 
they  are  continuous,  and  with  the  lymphatics,  wonderful  meshes  in  the 
tissue  of  our  organs. 

Several  physiologists  consider  the  capillary  blood-vessels  as  an  inter- 
mediate system  between  the  arteries  and  veins,  in  which  the  blood,  en- 
tirely out  of  the  influence  of  the  action  of  the  heart,  flows  slowly,  with  an 
oscillatory  and  sometimes  retrograde  motion,  is  no  longer  red,  because 
its  globules  are  strained,  as  it  were,  and,  in  a  manner,  lost  in  a  colourless 
serum,  which  serves  them  as  a  vehicle. 

It  is,  in  fact,  necessary,  that  bodies  should  be  of  a  certain  bulk,  to  re- 
flect the  rays  of  light  at  an  angle  sufficiently  obtuse,  that  the  eye  may  dis- 
cover their  colour.  We  know,  that  grains  of  saiid  reduced  to  a  very  fine 
dust,  appear  colourless,  when  examined  separately,  and  are  seen  to  pos- 
sess colour,  only  when  in  a  state  of  aggregation  :  further,  very  thin  lami- 
na of  a  horny  substance,  appear  transparent,  though  the  part  from  which 
they  have  been  detached  be  of  a  red  or  blue  colour.  But  if  several  of 
these  transparent  lamina  be  laid  on  one  another,  the  red  colour  becomes 
darker,  in  proportion  as  a  greater  number  are  brought  together. 

Let  irritation,  from  whatever  cause,  determine  the  blood  to  flow  into 
the  serous  capillary  vessels,  in  greater  quantity,  and  with  more  force, 
these  vessels  will  become  apparent,  the  "organs  in  whose  structure  they 
circulate,  will  acquire  a  red  colour,  more  or  less  deep;  thus  the  conjunc- 
tiva, the  pleura,  the  peritoneum,  the  cartilages,  the  ligaments,  &c.  which 
naturally,  are  whitish  or  transparent,  become  red,  when  affected  with 
inflammation,  whether  from  the  increased  impetus  of  the  circulation, 
which  forces  and  accumulates  into  the  capillary  vessels,  a  greater  num- 
ber of  red  globules,  or  that  the  sensibility  of  these  small  vessels  is  im- 


*  The  arterial  divisions  which  may  be  discerned  by  the  aid  of  anatomy,  do  not  ex- 
ceed eighteen  or  twenty  :  nevertheless,  they  divide  still  further,  when  they  are  become 
so  minute  us  not  to  be  discernible  without  the  help  of  the  most  powerful  microscope,—' 

Note. 


157 

paired  by  inflammation,  so  that  they  admit  globules  which  they  formerly 
rejected. 

Some  capillary  vessels  transmit  blood  at  all  times,  and  uniformly  ex- 
hibit a  red  colour  :  this  is  the  case  with  the  capillary  vessels  of  the  spleen, 
of  the  corpora  cavernosa  of  the  penis,  of  the  bulb  and  corpus  spongiosum 
of  the  urethra:  the  same  applies  to  the  capillaries  of  the  muscles  of  the 
mucous  membranes  :  there  arc,  however,  very  few  of  those  organs,  in 
v/hich  the  whole  portion  of  the  capillary  tube,  between  the  termination  of 
the  artery  and  the  origin  of  the  vein,  is  filled  with  red  blood.  There  is, 
almost  always,  a  division  in  the  tortuous  line  described  by  the  capillary, 
and  within  this  space,  the  blood  cannot  be  detected  of  its  usual  colour*. 

The  number  of  the  capillary  vessels,  as  well  as  that  of  the  arteries, 
to  which  the  former  are  as  auxiliaries,  is  much  more  considerable  in  the 
secretory  organs,  than  in  those  in  \$hich  life  carries  on  only  the  process 
of  nutrition.  It  is  on  that  account,  that  the  Ijones,  the  tendons,  the  liga- 
ments, the  cartilages,  contain  so  much  smaller  a  quantity  of  blood,  than 
the  mucous  and  serous  membranes,  and  the  skin.  The  capillary  vessels 
are,  however,  very  numerous,  in  the  muscles,  which  owe  that  colour  to 
the  great  quantity  of  blood  they  contain,  but  as  we  *hall  point  out,  when 
we  come  to  speak  of  motion,  this  fluid  appears  to  form  an  essential  ele- 
ment in  muscular  contraction;  it  is,  therefore,  not  to  be  wondered,  that 
these  organs  should  have  a  greater  number  of  capillary  vessels  sent  to 
them:  since  these  vessels  do  not  supply  them  merely  with  molecules  to 
carry  on  nutrition,  and  to  repair  the  waste  of  the  part,  but  to  impart  to 
them  the  principle  of  their  frequent  contraction ;  the  quantity  of  them  is 
so  considerable,  in  all  these  parts,  employed  in  the  two-fold  offices  of  nu- 
trition and  secretion,  that  Ruysch  penetrated,  with  his  injections,  the 
whole  thickness  of  their  substance,  to  such  a  degree,  that  the  organs  which 
he  had  prepared,  were  only  a  wonderful  and  inextricable  net-work  of  ca- 
pillary vessels  extremely  minute.  On  these  anatomical  preparations, 
made  with  an  art  hitherto  unrivalled,  Ruysch  grounded  his  hypothesis 
relative  to  the  intimate  structure  of  the  body,  in  which,  he  imagined,  all 
was  capillary  tubes,  an  hypothesis  which  has  obtained  the  most  favoura- 
ble reception,  and  has  reigned,  during  more  than  a  century  in  the  schools. 
It  is  enough  to  reflect  a  moment  on  their  uses,  to  conceive  that  the  num- 
ber of  them  must  be  really  prodigious.  As  long  as  the  blood  is  enclosed 
within  the  arteries,  and  flows  under  the  contrcul  of  the  heart,  it  fulfils  no 
purpose  either  of  nutrition  or  secretion.  To  make  it  subservient  to  these 
great  functions,  it  must  be  diffused  through  the  very  tis:,u<  of  the  organs, 
by  means  of  the  capillary  divisions;  these  little  vessels  exist  then,  in  every 
part,  where  any  organized  molecules  are  found  united ;  since  the  parti- 
cle formed  by  their  assemblage,  must,  at  least,  find,  in  the  juices  which 
they  bring  to  it,  the  materials  of  its  reparation.  Entering,  in  greater  or 
less  proportion,  into  the  organization  of  all  the  tissues,  the  capillaries  re- 
ceive certain  modifications  from  the  organs  of  which  they  are  an  integral 
part;  modifications  which  enable  them  to  deposit  the  serous  part  of  the 
blood  on  the  surface  of  the  serous  membranes,  admit  the  transudation  of 


*  There  is  every  reason  for  concluding  that  capillary  vessels  exist,  which,  running- 
between  some  of  the  terminations  of  the  arteries  and  the  commencement  of  veins,  ad- 
mit only  the  serous  portion  of  the  blood,  when  performing-  their  healthy  functions  ;  but 
which  may,  in  a  state  of  inflammation,  admit  also  the  red  particles  of  this  fluid  to  flow 
along  them. —  Copland 


158 

the  fat  into  the  cells  of  the  cellular  tissue,  furnish  the  urine  tp  the  kid- 
neys, and  the  liver  with  the  materials  of  the  bile :  in  a  word,  suffer  to  es- 
cape, through  the  porosities  with  which  their  pa^ietes  are  pierced,  the 
principles  which  the  blood  has  to  furnish  to  every  organ. 

It  is  by  these  lateral  porosities,  and  not  by  extremities  open  on  all  the 
surfaces,  and  in  all  the  points  of  the  organs,  that  the  capillaries  transpire, 
in  some  sort,  the  elements  of  nutrition,  and  of  the  various  secretions*. 
Mascagni  was  aware,  that  Nature,  skilful  in  deducing  many  effects  from 
few  causes,  has  not  deviated,  in  the  construction  of  the  system  of  circu- 
lation, from  the  invariable  laws  of  her  ordinary  simplicity;  but  the  lateral 
pores  of  the  capillaries,  which  are  sufficient  for  the  explanation  of  all  the 
phenomena  ascribed  to  the  exhaling  mouths  of  the  arteries,  and  to  the 
pretended  continuity  of  these  vessels  with  the  excretory  ducts  of  the  or- 
gans, Sec.  are  not  openings  like  the  |)ores  common  to  all  matter;  each  of 
them  may  be  considered  as  an  orifice,  sensible,  and,  especially  contractile, 
of  differing  size,  according  to  the  state  of  the  strength,  or  of  the  vital  pow- 
ers. The  size  then  of  these  capillary  pores  is  subject  to  frequent  varia- 
tions;  and  this  is  the  explanation  given  of  the  formation  of  scorbutic  ec- 
chymoses,  of  petechiae,  of  passive  or  relaxed  hemorrhages.  In  all  these 
affections,  contractility  being  really  diminished,  the  pores  of  the  capilla- 
ries enlarge,  and  suffer  the  red  blood  to  transude  through  their  relaxed 
mouths.  This  phenomenon  takes  place,  not  only  under  the  skin  and  on 
the  various  mucous  surfaces,  it  is  observed  also  in  the  very  tissue  of  the 
organs.  It  is  thus,  that  I  have  often  seen,  on  opening  the  bodies  of  those 
that  had  died  of  the  scurvy,  in  its  last  stage,  the  muscles  of  the  leg  filled 
with  blood.  This  sort  of  interior  hemorrhage,  converts  the  muscles  into 
a  kind  of  pulp;  and  the  extravasated  blood  itself  undergoes  a  beginning 
of  decomposition.  'I  he  bones  themselves  are  liable  to  these  scorbutic 
bloody  nitrations.  I  had  an  opportunity  of  ascertaining  this  in  the  Hos- 
pital of  St.  Louis,  at  the  same  time  that  I  learnt  the  difficulty  of  procuring 
a  durable  skeleton  from  such  bodies.  The  greatest  number  die,  in  a  very 
advanced  stage  of  the  disease,  and  the  bones  dissolve  in  maceration,  or 
rot  in  a  very  little  time. 

The  capillary  vessels,  whether  the  blood  flow  through  them  red,  or 
colourless,  are  not  a  system  of  vessels  distinct  from  that  of  the  arteries, 
and  from  that  of  the  veins:  they  belong  essentially  to  these  two  orders  of 
vessels.  Those  which,  ramifying  in  the  tissue  of  the  skin,  or  of  the  se- 
rous membranes,  suffer  the  serum  of  the  blood  to  transude,  are  not  more 
entitled  to  the  name  ofexhalent  system,  which  some  authors  have  given 
them.  To  consider  a?  distinct  and  insulated  systems,  separate  parts  of  a 
system  of  organs,  is  to  incumber  science  with  a  crowd  of  divisions,  as 
false  as  they  are  useless. 

LXI.  The  sanguineous  capillaries  anastomose,  and  form,  like  the  lym- 
phatic capillaries,  a  net-work  that  envelopes  all  the  organs.  Their  fre- 
quent communications  do  not  allow  obstructions  to  take  place,  and  to 
produce  inflammation,  as  Boerhaave  thought,  and  as  was  long  taught,  on 
the  authority  of  that  celebrated  physician-  Haller,  Spallanzani,  all  the 
microscopic  observers,  have  perceived  threads  of  blood  flowing  in  the  ca- 
pillaries, offering  themselves  at  the  various  inosculations  of  these  vessels, 


*  See  APPENDIX,  Note  S,  for  observations  on  the  functions  of  the  capillary  system  ; 
Jtnd  on  nutrition. 


159 

and  have  seen  them  flow  back,  when  they  were  not  admitted,  to  seek  other 
easier  entrances. 

I  will  not  collect,  in  this  place,  superfluous  arguments  against  the 
theory  of  the  Leyden  professor,  rejected  at  its  birth  by  the  physicians  of 
Montpellier,  absolutely  refuted,  and  now  universally  given  up.  Irritation 
alone  keeps  the  blood  in  the  inflamed  part ;  for,  when  death,  which  puts 
an  end  to  all  irritations,  and  relaxes  all  spasms  :  when  I  say,  death  comes 
on,  all  slight  inflammations  are  dissipated,  and  whenever  they  have  not 
been  sufficiently  intense,  to  induce  transudation  of  the  blood  through  the 
parietes  of  the  capillaries,  into  thecrco/a?  of  the  organic  tissues,  the  blood 
flows  back  into  the  large  vessels,  and  there  is  no  trace  of  it  left.  It  is  thus, 
that  erysipelas  of  the  skin  disappears,  that  the  pleura  preserves  its  trans- 
parency, in  individuals  affected,  before  death,  with  sharp  pains  in  the 
side.  If  to  this,  we  add  our  ignorance  on  the  real  organization  of  the 
nervous  system,  on  the  conditions  absolutely  required  of  the  brain  and 
nerves,  for  the  maintenance  of  life,  we  shall  cease  to  be  surprised,  that  the 
opening  of  bodies  has  taught  us  no  more  on  the  real  seat  of  disease,  and 
we  shall  confess  with  Morgagni,  who,  however  employed,  with  great  suc- 
cess, this  means  of  improving  the  art  of  healing,  that  there  are  number- 
less diseases,  of  which,  after  death,  no  trace  is  left,  and  for  the  fatal  ter- 
mination of  which,  we  are  unable  to  account. 

Contractility  and  sensibility  exist,  in  a  much  higher  degree,  in  the  ca- 
pillary and  serous  vessels,  than  in  the  veins  and  arteries.  Life  must  needs 
be  more  active  in  the  former,  for,  the  motion  given  to  the  blood  by  the 
contractions  of  the  heart,  being  exhausted,  this  fluid,  no  longer  in  the 
sphere  of  action  of  that  organ,  can  circulate,  viutfrom  the  influence  of  the 
action  of  the  vessels  themselves. 

The  termination  of  the  arteries  in  veins,  is  the  only  well  ascertained 
termination  of  those  vessels ;  it  may  be  seen  by  the  help  of  the  micro- 
scope, in  cold-blooded  animals,  in  frogs  and  salamanders.  In  some  fish, 
\ve  may,  even  with  the  naked  eye,  observe  frequent  and  considerable 
inosculations,  between  the  arteries  and  veins.  In  man,  however,  and  in 
other  warm-blooded  animals,  these  communications  take  place,  only 
at  the  extremities  of  the  two  systems  of  vessels.  In  this  case,  the  arte- 
ries terminate,  sometimes,  in  capillary  vessels  carrying  serous  fluid,  such 
as  the  vessels  of  the  sclerotic  coat;  these  vessels  become  small  veins 
whose  calibre  gradually  increases,  until  they  admit  red  globules  in  suf- 
ficient number  to  reflect  that  colour.  At  other  times,  the  artery  and  vein 
are  continuous,  without  the  intervention  of  that  extremely  minute  sub- 
division: the  red  blood  then  passes  readily  and  immediately  from  the  ar- 
tery into  the  vein*. 

It  will  be  shown,  in  speaking  of  secretion,  that  the  continuation  of  the 
arteries  into  the  excretory  ducts  of  the  conglomerate  glands,  and  their 
termination  in  exhaling  orifices,  cannot  be  admitted,  and  that  the  presence 
of  small  pores,  in  the  sides  of  the  minute  arteries  and  veins,  would  afford 
an  explanation  of  the  phenomena  on  which  the  belief  of  this  termination 
of  the  arteries  rests.  There  exists  no  parenchyma,  no  spongy  tissue,  be- 
tween the  extremities  of  the  arteries  and  the  origin  of  the  veins,  with, 
perhaps,  the  exception  of  the  substance  of  the  cavernous  bodies  of  the 


*  See  the  Chapter  on  the  Organs  of  Generation. 


160 

penis  and  of  the  clitoris,  of  the  bulb  and  spongy  part  of  the  urethra*,,  the 
retiform  plexus,  which  surrounds  the  orifice  of  the  vagina,  and,  perhaps, 
also,  the  tissue  of  the  spleen,  though  the  experiments  of  anatomists  (Mas- 
cagni  and  Lobstein)  seem  to  prove,  that  in  these  organs,  the  arteries  and 
veins,  are  immediately  continuous!. 

LXIL  Of  the  action  of  the  veins\.  These  vessels,  whose  functions  it  is 
to  carry  back  to  the  heart,  the  blood  which  the  arteries  have  sent  to  all 
the  organs,  are  much  more  numerous  than  the  arteries  themselves.  It  is 
observed,  in  fact,  that  arteries  of  a  middle  size,  as  those  of  the  leg  a^ 
fore-arm,  have  each  two  corresponding  veins,  whose  calibre,  at  leS^ 
equals  theirs,  and  that  there  is  besides,  a  set  of  superficial  veins,  lying 
between  the  skin  which  covers  th*>  limbs  and  the  aponeuroses  which  en- 
velope the  muscles:  these  have  no  corresponding  arteries.  The  space 
which  the  venous  blood  occupies  is,  therefore,  much  greater  than  that 
taken  up  by  the  blood  in  the  arteries.  Hence  also,  it  is  estimated,  that  of 
twenty-eight  or  thirty  pounds  of  this  fluid,,  making  about  a  fifth  part  of  the 
whole  weight  of  the  body  in  an  adult  man,  nine  parts  are  present  in  the 
veins,  and  only  four  in  the  arteries.  In  this  calculation,  one  should  con- 
sider as  arterial,  the  blood  contained  in  the  pulmonary  veins  and  in  the 
left  cavities  of  the  heart,  while  that  which  fills  the  cavities  in  the  right 
side  of  the  heart  and  the  pulmonary  artery  is  truly  venous,  and  has  every 
character  of  such  blood. 

Although  the  veins  generally  accompany  the  arteries,  and  are  united 
to  them,  by  a  common  sheath  of  cellular  membrane,  this  disposition  of 
parts  is  not  without  exceptions.  The  veins  which  bring  back  the  blood 
from  the  liver,  do  not,  in  any  respect,  foliovv  the  course  of  the  branches 
of  the  hepatic  artery  :  the  sinuses  of  the  brain  are  very  different,  in  their 
arrangement,  from  the  cerebral  arteries ;  the  veins  of  the  bones,  which 
are  particularly  numerous,  and  of  a  much  greater  calibre  than  the  arte- 
ries of  the  same  parts,  from  the  slow  circulation  of  the  blood  along  them, 
do  not  generally  follow  the  direction  of  the  arteries,  and  arise  singly  from 
the  substance  of  the  bone,  with  the  exception  of  those  in  the  middle  ca- 
nal, and  which  pass  through  the  nutritious  foramen  of  the  bone.  The 
veins  are  not  only  more  numerous  than  the  arteries,  but  they  are  like- 
wise more  capacious,  and  dilate  more  readily;  this  structure  was  neces- 
sary, on  account  of  the  slowness  with  which  the  blood  circulates,  and  of 
the  readiness  with  which  it  stagnates,  when  the  slightest  obstacle  impedes 


*  See  APPENDIX,  NoteN. 

-f  See  APPENDIX.  Note  T. 

t  In  the  month  of  February,  1823,  while  preparing  a  subject  for  the  demonstration  of 
the  arteries,  I  was  presented  with  the  most  satisfactory  evidence  of  the  direct  communi- 
cation between  the  arteries  and  veins.  Into  the  left  carotid  artery  of  an  adult  and  ema- 
ciated subject,  I  introduced  and  secured  a  large  sized  pipe,  pointing1  towards  the  chest. 
Into  this  was  thrown  with  the  ordinary  syringe,  melted  tallow,  highly  coloured  with 
King's  yellow.  The  injection  was  generally  minute,  more  particularly  so  in  the  arms, 
and  most  in  that  of  the  left  side.  In  the  arms,  not  only  were  the  arteries  filled,  but  the 
veins  of  the  smallest  size,  from  the  extremities  of  the  fingers  to  the  axilla,  were  entire- 
ly distended.  What  was  still  more  interesting,  the  tallow  in  the  arteries  was  of  a  very 
bright  yellow,  increasing  in  colour  as  the  arteries  became  smaller,  while  in  the  veins  the 
tallow  was  entirely  destitute  of  colour,  having  passed  through  vessels  too  small  to  allow 
the  colouring  matter  to  accompany  it.  Wherever  a  small  artery  could  be  seen  a  vein 
filled  with  the  pure  tallow  could<be  distinctly  observed. 

This  injection  was  demonstrated  before  a  large  class,  and  was  shown  to  several  mem- 
bers of  the  Academy  of  Natural  Sciences  of  Philadelphia. — Godman* 


161 

its  circulation  *  The  force  which  carries  on  the  circulation  of  the  blood, 
along  the  arteries,  is  so  great,  that  Nature  seems  not  to  have  availed  her- 
self of  the  mechanical  advantages  which  might  have  facilitated  its  flow.  On 
the  other  hand,  the  power  which  determines  the  progression  of  the  venous 
blood  is  so  feeble,  that  she  has  sedulously  removed  every  obstacle  which 
might  have  impeded  its  course;  and  as  the  relation  of  the  minute  to  the 
larger  branches,  of  these  to  the  trunk,  is  the  same  as  in  the  arteries,  two 
branches  unite  to  form  a  vein  of  greater  calibre  than  each  separate  ves- 
sel, but  smaller  than  the  two  taken  together,  the  blood  flows  along  a  space 
which  becomes  narrower,  the  nearer  it  approaches  the  heart ;  the  rapi- 
dity of  its  course  must,  therefore,  be  progressively  increased. 

The  veins  are  almost  straight  in  their  course  ;  at  least,  they  are  much 
less  tortuous  than  the  arteries.  The  force  which  makes  the  blood  flow 
along  them,  is  consequently  not  taken  up  in  straightening  these  curves  ; 
the  anastomoses  are,  likewise,  more  frequent,  and  as  the  flow  of  the 
blood  might  have  been  intercepted  in  the  deep  seated  veins  of  the  limbs, 
when  the  muscles,  among  which  these  vessels  lie,  during  contraction, 
compress  them  by  their  enlargement  and  induration,  they  communicate 
freely  with  the  superficial  veins,  towards  which  the  blood  is  carried,  and 
flows  the  more  readily,  as  they  are  not  liable  to  be  compressed.  It  is 
to  be  observed,  and  is  to  be  accounted  for  on  the  same  principle,  that  the 
superficial  veins  are  very  large  and  distinct  among  the  lower  orders  who 
are  employed  in  laborious  occupations,  requiring  an  almost  continual  ex- 
ertion of  their  limbs.  Lastly,  the  internal  part  of  the  veins,  like  that  of 
the  lymphatics,  is  furnished  with  valvular  folds,  formed  by  the  duplica- 
ture  of  their  epidermoid  coat.  These  valves,  which  are  seldom  single, 
and  almost  always  in  pairs,  are  not  found  in  the  minute  veins,  nor  in  the 
great  trunks,  nor  in  the  veins  which  bring  back  the  blood  from  the  vis- 
cera in  the  great  cavities. 

These  valves,  in  falling,  close  completely  the  canal  of  the  vessel,  de- 
stroy the  continuity  of  the  column  of  blood  returning  to  the  heart,  divide 
it  into  smaller  columns,  as  numerous  as  the  intervals  between  the  valves, 
and  the  height  of  which  is  determined  by  the  distance  between  these 
folds.  So  that  the  power  which  carries  onward  the  venous  blood,  and 
which  would  be  incapable  of  propelling  the  whole  mass,  acts  advantage- 
ously on  each  of  the  small  portions  into  which  it  is  divided. 

LXIII.  It  has  been  thought,  that  the  principal  cause  which  makes  the 
blood  flow  into  the  veins,  is  the  combined  action  of  the  heart  and  arteries; 
but  the  impulse  from  those  organs,  is  lost  in  the  system  of  capillary  ves- 
sels, and  does  not  extend  to  the  veins.  The  specific  action  of  their  own 
parietes,  aided  by  auxiliary  means,  such  as  the  motion  of  the  neighbour- 
ing arteries,  is  sufficient  to  carry  the  blood  on  to  the  heartf. 


*  The  arteries  contain,  at  all  times,  nearly  the  same  quantity  of  blood.  The  veins 
are  always  the  seat  of  plethora,  because  the  blood  stag-nates  in  them  more  readily;  and 
this  condition  brings  an  inflammatory  fever  (consisting'  merely  in  an  increased  action  of 
the  vascular  system,  as  is  expressed  by  the  term  ungeioteniqite  applied  to  it  by  Professor 
PineV)  only  when  the  venous  congestion  becoming-  excessive,  the  blood  passes  with 
difficulty  from  the  arteries  into  the  veins.  The  heart  and  the  arteries  then  struggle, 
with  considerable  effort,  to  rid  themselves  of  the  fluid  which  oppresses  them,  &c. — 
Jiuthor't  Note. 

•{•  In  the  process  of  returning  the  blood  to  the  heart,  two  causes  are  principally  en- 
gaged, the  most  efficient  of  which  is,  undoubtedly,  the  contractile  power  of  the  vein$ 
themselves,  AVe  are  aware  that  this  property  is  denied  to  them  by  many  who  have 


162 

These  panetes,  which  are  much  thinner  than  those  of  the  arteries,  are 
contained,  like  theirs,  in  a  sheath  common  to  all  the  vessels.  Three  coats, 
likewise,  enter  into  their  structure  ;  the  middle  or  fibrous  coat  is  not  very 
distinct,  and  consist  merely  of  a  few  longitudinal  reddish  fibres,  which  can 
be  distinguished  only  in  the  larger  veins,  near  the  heart.  In  some  of  the 
larger  quadrupeds,  as  in  the  ox,  these  fibres  form  distinct  fasciculi,  and 
their  muscularity  is  much  more  manifest. 

The  internal  coat,  which  is  more  extensible  that  that  of  the  arteries, 
and  equally  thin,  adheres  more  closely  to  the  other  coats.  The  cellular 
coat,  which  connects  it  to  the  middle  one,  is  less  abundant,  hence  phos- 
phate of  lime  is  seldom  deposited  into  it,  as  happens  to  the  arteries  which 
frequently  become  ossified,  as  we  advance  in  years.  This  internal  coat  is 
merely  a  continuation  of  that  which  lines  the  cavities  of  the  heart;  and  as 
the  origin  of  the  inner  coat  of  the  arteries  is  the  same,  there  exists  a  non- 
interrupted  continuity  in  the  membrane  which  lines  all  the  canals  of  the 
circulation.  The  inner  coat  forms  the  only  essential  part  of  the  venous 
system;  it  alone  constitutes  the  veins  within  the  bones,  the  sinuses  of  the 
dura  mater,  the  hepatic  veins,  in  a  word,  all  the  veins  which  are  so  firmly 
attached  externally  to  the  neighbouring  parts,  that  the  blood  flows  along 
them,  as  along  inert  tubes,  their  parietes  being,  almost  completely  inca- 
pable of  contracting. 

The  veins,  in  their  passage  through  muscles,  are,  like  the  arteries, 
guarded  by  aponeurotic  rings,  than  which  is  more  remarkable  than  that 
which  belongs  to  the  aperture  in  the  diaphragm,  which  transmits  the  as- 
cending cava  from  the  abdomen  into  the  thorax.  This  vessel  is,  therefore, 
not  compressed  by  the  contraction  of  that  muscle  in  inspiration. 

LXIV.  As  the  inferior  cava  passes  through  the  lower  edge  of  the  liver, 
whether  along  a  deep  fissure,  or  in  a  real  canal  in  the  parenchymatous 
substance  of  that  viscus,  the  course  of  the  blood  must  be  impeded,  when, 
from  congestion  of  the  parenchyma,  the  vessel  is,  in  some  sort  strangu- 
lated. 

Obstruction  of  the  liver,  which  is  of  such  frequent  occurrence,  would 
have  been  attended  with  fatal  consequences,  by  preventing  the  return  of 
the  blood  from  the  inferior  parts,  along  the  ascending  cava,  if  this  great 
venous  trunk  did  not  keep  up,  by  means  of  the  vena  azygos,  an  open  and 
free  communication  with  the  descending  or  superior  cava.  The  use  of 
this  anastomosis  of  the  two  great  veins  is,  evidently,  to  facilitate  the  pas- 
sage of  the  blood  from  the  one  of  these  vessels  into  the  other,  when  either, 
especially  the  lower,  does  not  readily  evacuate  its  contents  into  the  right 
auricle.  On  this  account,  the  vena  azygos  is  capable  of  considerable 
dilatation,  and  is  entirely  without  valves.  In  the  body  of  a  man  opened, 
in  my  presence,  and  whose  liver  was  twice  as  large  as  in  health,  I  ob- 


speculated  on  the  subject.  It  is,  however,  shown  by  Haller,  that  the  vena  cava,  at 
least,  is  muscular,  and  Verschuyr  and  other  respectable  physiologists,  have  detected 
the  same  structure  in  the  most  minute  veins.  There  is  one  act  which  xve  think  ought 
alone  to  convince  us  of  the  contractility  of  these  vessels,  which  is,  that  they  always 
adapt  themselves  to  the  quantity  of  blood  they  contain. 

Co-operating  with  the  above  cause  is  the  action  of  the  muscles,  as  may  be  illustrated 
by  the  familiar  example  of  venaesection.  When  in  this  case  the  blood  issues  languidly 
from  the  orifice  made  in  the  vein,  it  is  known,  that  nothing  promotes  its  flow  so  effec- 
tually as  pressing  something  hard  in  the  hand.  This  operates  simply  by  bringing  into 
action  the  muscles  of  the  fore-arm  and  humerus,  thereby  producing  considerable  com- 
pression of  the  veins.—  Chapman. 


163 

served,  that  the  vena  azygos,  which  was  distended  with  blood,  was  of 
the  size  of  the  little  linger  ;  the  termination  downward  of  this  vessel,  in 
the  right  renal  vein,  and  above  in  the  superior  cava,  were  most  distinct, 
and  by  compressing  it  from  above  downward,  or  from  below  upward,  the 
blood  flowed  into  one  or  the  other  of  these  vessels. 

As  the  causes  which  determine  the  circulation  of  the  venous  blood, 
communicate  to  it  an  impulse  which  is  far  from  rapid,  and  as  this  fluid 
meets  with  only  trifling  obstacles,  and  such  as  are  easily  overcome,  the 
pressure  against  the  parietes  of  the  veins  is  very  inconsiderable,  and  these 
vessels  do  not  pulsate,  as  the  arteries.  There  is  observed,  however, 
near  the  heart,  an  undulatory  motion,  which  the  blood  communicates  to 
the  parietes  of  the  vessels.  These  kinds  of  alternate  pulsations  depend  on 
the  rapidity  with  which  the  blood,  whose  course  is  progressively  accele- 
rated, flows  towards  the  heart,  and  on  the  reflux  of  the  blood,  during  the 
contraction  of  the  right  auricle.  The  contraction  of  this  cavity,  forces 
back  the  blood  into  the  veins  which  open  into  it;  this  retrograde  course 
is  manifest  in  the  superior  cava,  and  is  the  more  readily  occasioned,  as  the 
orifice  of  this  vein  is  not  furnished  with  any  valve  that  might  prevent  it. 
It  does  not,  however,  extend  very  far  towards  the  brain,  the  blood  having 
to  ascend  against  its  own  weight,  and  the  jugulars  admitting  of  considera- 
ble dilatation.  This  regurgitation  is  still  more  marked  in  the  inferior  cava, 
the  orifice  of  which  is  but  imperfectly  closed  by  the  valve  of  Eustachius ; 
it  is  felt  in  the  abdominal  veins,  and  extends  even  to  the  external  iliacs,  ac- 
.  cording  to  the  testimony  of  Haller. 

LXV.  The  orifice  of  the  great  coronary  being  exactly  covered  over  by 
its  valve,  the  blood  does  not  return  into  the  tissue  of  the  heart,  which 
being  a  contractile  organ,  would  have  had  its  irritability  impaired  by  the 
presence  of  venous  blood.  It  is  of  consequence  to  observe,  that  this  re- 
flux never  extends  to  the  veins  which  bring  back  the  blood  from  the  mus- 
cles, and  that  it  is  never  felt  in  the  veins  of  the  limbs  which  are  furnished 
internally  with  valvular  folds.  The  case  is  very  different,  between  our  or- 
gans of  motion  and  these  secretory  glands  :  towards  these  the  blood  re- 
quired to  be  sent  back,  so  as  to  be  the  longer  exposed  to  their  action  :  ve- 
nous blood  diminishes  and  even  destroys  muscular  irritability,  and  is  truly 
oppressive,  as  may  be  ascertained  by  injecting  some,  in  the  arteries  of  a 
living  animal,  or  else  by  tying  the  veins,  so  as  to  prevent  its  return,  or 
by  observing  what  happens,  when  the  course  of  the  blood  is  interrupted, 
either  by  applyingfirm  ligatures  round  the  limbs,  or  by  wearing  confined 
clothes. 

I  am  satisfied,  that  it  was  from  observing  the  oscillatory  undulations  of 
the  venous  blood,  in  the  great  vessels,  that  the  ancients  were  led  to  the 
opinions  they  entertained  on  the  course  of  the  blood,  which  they  com- 
pared to  the  Euripus,  whose  waves  are  represented  by  the  poets,  as  un- 
certain in  their  course,  and  in  currents  running  in  contrary  directions. 

The  internal  veins  in  which  this  reflux  is  observed,  show  this  motion  of 
the  blood  most  distinctly  of  any;  their  sides  which  are  thin  and  semi- 
transparent,  not  being,  as  in  other  parts,  surrounded  by  an  adipose  cellu- 
lar tissue.  To  give  a  complete  notion  of  the  doctrine  of  the  ancients,  on 
the  subject  of  the  circulation,  it  will  merely  be  necessary  to  add  to  the 
above  idea,  the  opinion  which  they  entertained,  that  the  chyle  taken  up 
by  the  meseraic  veins,  was  carried  to  the  liver,  in  which  its  sanguification 
was  effected  ;  and  lastly,  that  the  arteries  were  filled  with  vital  spirit,  and 


164 

contained  only  a  few  drops  of  biood  which  passed  through  small  hole&> 
which,  Galen  says,  perforate  the  septum  of  the  ventricles. 

The  blood,  however,  continually  urged  on  by  the  columns  which  fol- 
low each  other  in  succession,  by  the  action  of  the  veins  whose  parietes 
become  gradually  stronger,  and  by  the  compression  which  these  vessels 
experience  from  the  viscera,  during  the  motion  of  respiration,  reaches 
the  heart,  and  enters  the  auricles  with  the  greater  facility,  as  the 
orifices  of  the  cavae  not  being  directly  opposed  to  each  other,  the  co- 
lumns of  blood  which  they  convey,  do  not  meet,  and  do  not  oppose  each 
other. 

LXVI.  The  blood  continually  carried  to  all  parts  of  the  body  by  the 
arteries,  returns,  therefore  to  the  heart,  by  a  motion  which  can  never  be 
interrupted,  without  considerable  danger  of  life.  We  know  that  the  cir- 
culation is  thus  effected,  from  the  direction  of  the  valves  of  the  heart,  of 
the  arteries  and  veins;  by  what  happens,  when  these  vessels  are  opened, 
compressed,  or  tied,  or  when  a  fluid  is  injected  into  them.  When  an 
artery  is  wounded,  the  blood  comes  from  the  part  of  the  vessel  nearest 
the  heart:  it  comes,  on  the  contrary,  from  towards  the  extremities,  if  it 
is  a  vein  that  has  been  opened.  By  compressing  or  tying  an  artery,  the 
course  of  the  blood  is  suspended  below  the  ligature,  and  the  vessel 
swells  above.  The  veins,  on  the  contrary,  when  tied  or  compressed,  di- 
late below.  Lastly,  when  an  acid  fluid  is  injected  into  a  vein,  the  blood 
is  seen  to  coagulate  in  the  direction  of  the  heart.  By  the  help  of  the  mi- 
croscope, we  may  see  in  the  semi-transparent  vessels  of  frogs  and  other 
cold-blooded  animals,  the  blood  flowing  from  the  heart  into  the  arteries, 
and  from  these  into  the  veins,  which  return  it  to  the  heart.  It  was  on 
the  strength  of  these  convincing  proofs,  that  William  Harvey  established, 
towards  the  middle  of  the  seventeenth  century,  the  theory  of  the  circula- 
tion qf  the  blood.  Its  mechanism  had  rather  been  guessed  at,  than  un- 
derstood, by  several  authors.  Servetus  and  Cesalpinus  appear  to  have- 
been  acquainted  with  it*;  but  no  one  has  more  clearly  explained  it  than 
the  English  physiologist,  who  is  justly  considered  the  author  of  that  im- 
mortal discovery. 

LXVII.  The  theory  of  Harvey,  such  as  it  is  laid  down  in  his  work, 
entitled,  De  sanguinis  circuitu^  extrcitationes  anatomicx,  does  not  appear 
to  roe  entirely  admissible.  He  considers  the  heart  as  the  only  agent 
which  sets  the  blood  in  motion,  and  does  not  take  into  account  the  action 
of  the  veins  and  arteries,  which  he  considers  as  completely  inert  tubes, 
while  every  thing  tends  to  prove  that  the  arteries  and  veins  assist  the  mo- 
tion of  the  blood  by  an  action  peculiar  to  themselvesf.  He  admits,  that 
the  blood  flows  in  every  part  of  the  circulatory  system,  with  an  uniform 
degree  of  speed;  an  opinion  so  manifestly  contradicted  by  reasoning  and 
experience,  which  prove  that  the  velocity  of  its  course  diminishes,  the 
greater  its  distance  from  the  heart,  from  the  influence  of  a  great  number 
of  circumstances,  which  it  would  be  useless  to  repeat  (LV1I.)  This 
doctrine  has  yet,  however,  several  abettors,  and  among  the  moderns, 
Spallanzani  has  endeavoured  to  support  it,  by  a  number  of  experiments 

*  Their  "  acquaintance"  with  the  circulation  was  nothing  better  than  mere  guessing. 
The  passages  of  their  works  referring  to  this  subject,  maybe  seen  in  the  introduction 
to  Harvey — Godman. 

j  See  APPENDIX*  Notes  A,  B,  S,  T. 


165 

so  contradictory,  that  one  is  surprised  that  so  judicious  a  physiologist 
should  have  collected  them  to  establish  a  theory  completely  refuted  by 
several  of  them.  Nothing,  for  example,  contradicts  it  more  fully,  than 
the  continuation  of  the  flow  of  the  blood,  in  the  vessels  of  frogs  and  sa- 
lamanders, after  the  hearts  of  these  reptiles  have  been  torn  out:  there 
are,  besides,  animals  which,  not  possessed  of  that  central  organ,  have 
nevertheless,  vessels  along  which  the  blood  flows,  and  which  contract 
and  dilate,  by  alternate  motions. 

If  the  mere  force  of  the  heart  propelled  the  blood  to  every  part,  the 
course  of  this  fluid  ought,  at  intervals,  to  be  suspended,  its  circulation, 
at  least,  ought  to  be  slackened,  when  the  ventricles  cease  to  contract; 
but  as  the  contraction  of  the  arteries  corresponds  to  the  relaxation  of  the 
ventricles,  these  two  powers,  whose  action  alternates,  are  continually 
employed  in  propelling  the  blood  along  its  innumerable  channels. 

Besides  the  general  circulation,  of  which  the  laws  and  phenomena 
have  just  been  mentioned,  each  part  may  be  said  to  have  its  peculiar 
mode  of  circulation,  more  or  less  rapid,  according  to  the  arrangement 
and  structure  of  its  vessels.  Each  of  these  individual  circulations  forms 
a  part  of  the  machinery  included  in  the  great  circle  of  the  general  circu- 
lation, and  in  which  the  course  of  the  blood  takes  place  in  a  different 
manner,  may  be  accelerated  or  retarded,  without  affecting  the  general 
circulation.  Thus,  in  a  whitlow  of  a  finger,  the  radial  artery  pulsates 
a  hundred  times  in  a  minute,  while  on  the  sound  side,  its  beats  are  only 
seventy  in  number,  and  perfectly  isochronous  with  the  pulsations  of  the 
heart*.  In  the  same  manner,  the  blood  of  the  intestines,  which  is  des- 
tined to  furnish  the  materials  of  bile,  flows  much  more  slowly  than  that 
of  other  parts. 

These  modifications  affecting  the  velocity  of  the  circulatory  motion  of 
the  blood,  account  for  the  difference  of  its  qualities  in  different  organs; 
all  these  differences  form  a  part  of  the  plan  of  nature,  and  it  is  not  difficult 
to  understand  their  utility. 

LXVIII.  In  what  has  been  said  of  the  circulation,  no  separate  mention 
has  been  made  of  the  course  of  the  blood  through  the  lungs,  called  by 
authors  the  lesser  or  pulmonary  circulation.  The  vascular  system  of  the 
lungs,  with  the  addition  even  of  the  cavities  of  the  heart  which  belong  to 
it,  does  not  represent  a  complete  circle,  it  is  only  a  segment,  or  rather 
an  arch  of  the  great  circle  of  general  Circulation. 

The  blood,  in  going  along  that  great  circle,  meets  with  the  organs, 
situated  like  so  many  points  of  intersection  in  the  course  of  the  vessel 
which  form  that  circle. 

To  render  still  more  simple,  the  idea  which  is  to  be  entertained  on  the 
subject,  one  may  reduce  these  intersections  to  two  principal  ones;  the 
one  corresponding  to  the  lungs,  the  other  to  the  rest  of  the  body;  the 
veins,  the  right  cavities  of  the  heart,  and  the  pulmonary  artery  with  its 


*  This  assertion  is  altogether  too  roundly  made,  and  appears  rather  to  be  one  of 
those  things  which  are  received  as  true  from  having  been  often  repeated,  than  the  ac- 
curate detail  of  a  well  observed  fact.  That  there  may  be  a  difference  in  the  degree  of 
dilatation  and  force  of  pulsation  in  different  arteries  is  well  known,  and  may  depend  on 
the  peculiar  condition  of  the  nerves  supplying  the  affected  vessels,  but  that  one  radial 
artery  should  beat  one  hundred  strokes  in  "a  minute,  while  the  other  beats  but  seventy* 
presupposes  the  existence  of  a  power  in  the  arteries  themselves  which  has  never  yet 
been  fnwed,  however  often  it  may  have  been  supposed. — Godmafi, 


166 

divisions,  forming  one-half  of  the  circle;  the  pulmonary  veins,  the  left 
cavities  of  the  heart,  the  aorta  with  all  its  branches  representing  the 
other  half.  The  capillary  vessels  of  the  lungs  form  one  of  the  points  of 
intersection,  and  the  capillaries  of  all  the  other  organs,  represent  the  other 
point  of  intersection,  by  uniting  together  the  arteries  and  veins  of  the 
whole  body,  in  the  same  manner  as  those  of  the  lungs  establish  a  com- 
munication between  the  veins  and  arteries  of  these  organs. 

This  division  of  the  system  of  circulation  into  two  parts,  in  one  of  which 
there  circulates  a  dark  or  venous  blood,  while  the  other  contains  red  or 
arterial  blood,  is  at  once  more  simple  and  more  accurate.  As  was  alrea- 
dy stated,  in  the  history  of  the  circulation,  that  its  organs  are,  in  an  espe- 
cial manner  destined  to  the  mechanical  act  of  conveying  the  fluids:  the 
changes,  the  alterations  which  the  blood  undergoes  in  passing  through 
the  organs,  are  affected,  only  at  the  moment  when  in  penetrating  into 
their  tissue,  it  passes  into  the  capillary  vessels  which  are  distributed 
into  them.  The  columns  of  blood  are  then  sufficiently  minute,  to  be 
operated  upon  by  the  vital  action;  till  then,  the  columns  of  blood  are  too 
large,  and  resist,  by  their  bulk,  if  one  may  so  speak,  any  decomposition. 
It  is,  therefore,  in  the  capillary  vessels,  that  the  blood  receives  its  essen- 
tial principles;  and  to  understand  how  the  nutritious  lymph  which  is 
deposited  by  the  thoracic  duct  in  the  left  subclavian  vein,  experiences, 
in  its  course  along  the  sanguiferous  system,  the  changes  which  are  to 
assimilate  it  to  our  own  substance,  it  is  necessary  to  follow  it,  along  the 
venous  blood  with  which  it  unites,  into  the  heart,  through  the  right  half 
of  which  it  passes  in  its  way  to  the  lungs,  there  to  combine  with  the  at- 
mospherical air,  from  which  we  are  perpetually  deriving  another  aliment 
indispensable  to  life;  then  to  examine,  how,  when  modified  and  conveyed 
with  the  red  blood,  from  the  lungs  to  the  whole  body,  it  serves  to  the 
secretions,  and  supplies  nourishment  to  the  whole  body. 

In  considering,  in  this  manner,  the  circulation  of  the  blood,  with  a  re- 
ference to  the  changes  which  it  undergoes  in  the  organs  through  which 
it  passes,  in  describing  that  circle,  we  shall  find,  that  this  fluid,  already 
combined  with  the  lymph  and  chyle,  parts,  in  the  lungs,  with  some  of  its 
principles,  at  the  same  time  that  it  becomes  impregnated  with  the  vital 
portion  of  the  atmosphere,  which  suddenly  changes  its  colour  and  other 
qualities.  The  blood  will  then  be  seen  to  flow  into  a!l  the  parts  which  it 
stimulates,  to  keep  up  their  energy,  to  awaken  their  action,  and  furnish 
them  the  materials  of  the  fluids  which  they  secrete,  or  the  molecules  by 
which  they  grow  or  are  repaired;  so  that  in  supplying  thus  the  different 
organs,  the  blood  loses  all  the  qualities  which  it  had  acquired  by  the  union 
of  the  chyle  and  of  the  vital  air,  parts  with  the  principles  to  which  it 
owed  its  colour,  and  again  becomes  dark,  to  be  repaired  anew  by  com- 
bining with  the  lymph,  and  by  the  absorption  of  the  vital  part  of  the  at- 
mospherical air*:  this  constitutes  the  principal  phenomenon  of  the  func- 
tion, which  will  be  considered  in  the  fourth  chapter. 


*  See  the  Notes  on  Respiration,  in  the  APPENDIX,  for  a  different  opinion. 


167 


CHAPTER   IV. 

OF  RESPIRATION. 


LXIX.  OF  the  different  changes  which  the  blood  undergoes  in  the 
different  organs,  none  are  more  essential  or  more  remarkable  than  those 
it  receives  from  the  air,  which,  during  respiration,  is  alternately  received 
into  the  lungs,  and  expelled  from  them.  The  blood  which  the  veins 
convey  to  the  heart,  and  which  the  right  ventricle  transmits  to  the  lungs, 
is  of  a  dark  colour,  and  heavy:  its  temperature  is  only  thirty  degrees 
(Reaumur's  thermometer;)  if  laid  by,  it  coagulates  slowly,  and  there  is 
separated  from  it  a  considerable  quantity  of  serum.  The  blood  which  is 
brought  by  the  pulmonary  veins  to  the  left  side  of  the  heart,  and  which 
is  conveyed  to  all  parts  of  the  body,  by  means  of  the  arteries,  is,  on  the 
contrary,  of  a  florid  red  colour;  it  is  spumous,  lighter,  and  warmer  by 
two  degrees.  It  likewise  coagulates  more  readily,  and  contains  a  smaller 
quantity  of  serum.  All  these  differences,  which  are  so  easily  distin- 
guished, depend  on  the  changes  which  it  has  undergone,  by  being  in 
contact  with  the  atmospherical  air. 

LXX.  Of  the  Atmosphere.  The  mass  of  air  which  surrounds  the  globe, 
and  to  which  we  give  the  name  of  atmosphere,  bears  on  all  bodies  with 
a  pressure  proportioned  to  their  surface.  That  of  man*  bears  a  weight 
of  air  amounting  to  about  thirty-six  thousand  pounds.  Moreover,  one  of 
its  constituent  principles  is  absolutely  necessary  to  the  keeping  up  of 
life,  of  which  it  is  a  principal  agent. 

The  variations  in  the  weight  of  the  atmosphere  have,  in  general,  but 
little  influence  on  the  exercise  of  the  functions;  nevertheless,  when  by 
ascending  the  tops  of  very  high  mountains,  man  rises  several  thousand 
fathoms  above  the  level  of  the  sea,  the  very  remarkable  diminution  of 
the  weight  of  the  air,  produces  a  very  sensible  effect.  Respiration  be- 
comes laborious  and  panting,  the  pulse  is  quickened,  and  there  is  felt  an 
universal  uneasiness,  joined  to  excessive  weakness,  and  haemorrhages 
come  on:  these  symptoms  are  occasioned  both  by  the  diminished  pres- 
sure of  the  air,  and  by  the  smaller  quantity  of  oxygen  contained  in  a 
rarer  atmospheref. 


*  The  surface  of  the  body  is  estimated  at  fifteen  or  sixteen  square  feet,  in  a  man  of 
middle  size. 

f  Several  travellers,  whose  reports  on  the  subject  I  have  consulted,  agree  in  repre- 
senting the  corporeal,  as  well  as  some  of  the  mental  functions,  to  be  very  strangely  in- 
fluenced by  a  rarified  condition  of  the  atmosphere.  But  the  celebrated  be  Saussure,  a 
writer,  who  unites  to  the  profundity  of  philosophical  research,  the  polish  of  literary  re- 
finement, has  from  personal  experience  described  these  affections  with  the  most  pre- 
cision. To  his  description,  I  shall,  therefore,  principally  adhere  in  the  ensuing1  inquiry. 

He  states,  that  at  a  certain  height  above  the  level  of  the  sea,  there  uniformly  takes 
place  a  sudden  and  uncommon  exhaustion  of  the  muscular  power.  The  natives  of  the 
Alps,  who  can  climb  for  hours  at  the  foot  of  the  mountains  without  being  at  all  wea- 
ried, are  forced  TO  stop,  and  take  breath  every  few  minutes,  when  they  ascend  the 


168 

The  human  body  resists,  without  any  effort,  the  atmospherical  pres- 
sure, because  it  is  applied  at  all  times,  and  in  every  direction.  But  if 
a  part  of  its  surface  ceases,  for  a  moment,  to  be  under  its  influence,  it 
swells,  the  fluids  are  determined  to  it,  in  considerable  quantity,  the  in- 
teguments become  excessively  distended,  so  as  to  be  in  danger  of  burst- 
height  of  fourteen  or  fifteen  hundred  toises.  Those  who  are  less  accustomed  to  the 
air  of  the  mountains,  are  obliged  to  rest  much  more  frequently.  So  intolerable,  indeed, 
is  the  fatigue  induced  in  this  situation,  that  the  person  suffering  it,  is  rendered  some- 
times wholly  incapable  of  motion.  If  he  attempt  to  move,  his  legs  sink  under  him,  his 
heart  palpitates,  his  arteries  throb,  his  head  becomes  g'iddy,  his  eyes  are  dazzled,  and, 
to  avoid  fainting,  he  is  forced  to  sit  doww.  Near  the  top  of  Mont  Blanc,  our  traveller 
could  not  advance  more  than  a  few  steps  without  stopping  to  respire,  and  on  the  sum- 
mit of  it,  though  his  exertions  were  moderate,  he  was  constrained  frequently  to  desist 
altogether  from  them,  and  breathe  laboriously  to  recruit  his  strength.  With  this  exces- 
sive degree  of  fatigue,  accelerated  pulse,  and  difficult  respiration,  there  is  great  thirst, 
sickness  of  stomach,  a  loathing  of  food,  and  an  aversion  to  every  species  of  spirituous 
liquor.  But  what  is  very  extraordinary,  these  affections  are  as  short  in  their  duration, 
as  they  are  violent. 

These  effects  are  not  peculiar  to  the  human  species.  The  same  writer  relates,  that 
the  mules  which  tie  employed  to  carry  his  baggage,  became  suddenly  so  weak  and  ex- 
hausted that  they  could  hardly  walk,  even  when  the  burden  was  removed  from  their 
backs.  They  staggered  as  they  moved ;  their  respiration  was  panting  and  difficult,  and 
seemingly  attended  with  painful  sensations  of  the  chest,  as  they  uttered  plaintive  and 
distressing  cries. 

After  resting  a  few  minutes,  the  sense  of  fatigue  is  so  completely  dissipated,  tbat  the 
person,  in  resuming  his  journey,  feels  such  a  renovation,  that  he  is  persuaded  he  will 
be  able  to  prosecute  it  uninterruptedly.  He,  however,  is  soon  disappointed.  On 
moving  a  short  distance  only,  his  former  inability  returns,  and  his  progress  is  again  ar- 
rested. An  additional  effect  of  this  state  of  the  atmosphere,  is  an  almost  irresistible 
propensity  to  sleep.  We  are  told,  that  if  the  attention  of  the  person  be  not  engaged, 
and  kept  excited,  he  will,  wh<>n  pausing  to  rest,  often  fall  to  sleep  almost  instantane- 
ously, though  annoyed  by  the  wind  or  cold,  the  light  or  heat  of  the  sun,  and  in  the 
most  incommodious  and  disagreeable  posture  of  his  body.  This  sleep  sometimes,  ap- 
proaches in  soundness  nearly  to  lethargy.  It  may  also  be  observed,  that  aeronauts  have 
generally  mentioned  drowsiness  as  one"  of  the  consequences  produced  by  the  attenu- 
ated atmosphere  of  the  exalted  regions  which  they  explore  in  their  excursive  flights, 
and  some  have  even  declared  that  they  slept  soundly,  when  at  the  utmost  pitch  of  their 
perilous  adventures. 

Nothing  affords  the  least  relief  to  any  of  the  symptoms  enumerated,  except  rest  and 
cold  -water.  Cordials  and  spirituous  liquors  aggravate  all  the  complaints. 

Now,  in  what  manner  are  these  singular  affections  to  be  explained  ?  We  believe, 
with  our  author,  that  they  are  in  part  owing  to  the  diminished  pressure  of  the  atmo- 
sphere, but  infinitely  more  to  a  deficiency  of  oxygen. 

It  is  clearly  ascertained,  that  respiration  supports  animal  life,  and  all  its  actions.  This 
process  requires  the  presence  of  two  principles.  These  are  oxygen  and  combustible 
matter.  The  former  is  supplied  chiefly  through  the  medium  of  the  lungs,  and  the  lat- 
ter by  the  stomach.  Of  the  vital  actions,  none  seems  to  be  more  immediately  depem 
ent  and  strikingly  regulated  by  respiration  than  the  muscular.  It  is  not,  however,  my 
design  to  dwell  on  the  relation  between  them.  It  is  sufficient  for  my  purpose  to  re- 
mark, that  during  exercise  a  greater  quantity  of  oxygen  is  extracted  from  the  atmosphere 
by  the  lungs,  and  that  carbonic  acid  and  water  are  formed,  and  caloric  evolved  in  cor- 
responding proportions.  Hence  it  may  be  deduced,  that  during  muscular  exertion, 
there  is  a  greater  demand  for  oxygen,  and  a  larger  consumption  of  combustible  matter.  It 
also  follows,  that  if  the  preceding  premises  be  admitted,  as  a  legitimate  corollary,  that 
the  same  effect  would  be  produced,  namely,  an  exhaustion  of  the  muscular  vigour,  by 
withholding  the  one  or  the  other  of  these  agents.  In  either  case,  fatigue  will  be  caused, 
and  the  body  rendered  incapable  of  muscular  exertion.— But  the  incapacity  in  the  two 
:s  arises  from  different  states  of  the  svstem,  and  will  be  distinguished  by  different 


cases  ases 


appearances,  and  removed  by  different  methods  of  treatment. 

Limited  exercise  in  an  atmosphere  of  sufficient  density,  slowly  deprives  the  body  oi 
its  proper  quantity  of  combustible  matter,  until  fatigue  is  finally  induced.  The  body 
is  afterwards  gradually  recruit-rt  by  rest  and  food,  or  directly  restored  to  momentary 


169 

ing$  such  are  the  phenomena  which  attend  the  application  of  cupping 
glasses. 

The  pressure  of  the  air,  on  the  surface  of  the  globe  is  necessary  to  the 
existence  of  bodies  in  the  condition  in  which  we  see  them.  Several  very 
volatile  fluids,  as  alcohol  and  ether,  would  become  gaseous,  under  a  less 
pressure  of  ^ie  atmosphere;  water  would  boil,  under  eighty  degrees 


strength  by  the  use  of  spirituous  liquors,  which  are  pure  combustible  matter  mixed 
with  water. 

Hut  in  the  elevated  regions  of  the  atmosphere  where  there  is  a  deficiency  of  oxygen, 
the  fatigue  which  comes  on  is  of  an  opposite  kind.  It  arises  from  an  over-propwtion  of 
combustible  matter,  and  a  want  of  oxygen*  ^Here,  of  course,  it  is  alleviated  by  rest,  and 
deep  inspirations,  and  exacerbated  by  exercise  and  spirituous  liquors. 

It  is  suddenly  induced,  because  the  pulmonary  system  is  so  contrived,  that  the  body 
at  no  instant  receives  more  oxygen  than  what  at  the  instant  it  requires.  We  are  in- 
structed by  experiments,  that  animals  placed  in  a  vessel  filled  with  oxygen,  and  respir- 
ing the  gas  in  a  state  of  purity,  do  not  consume  more  of  it  than  when  combined  with 
irrespirable  gas.  Thus,  it  takes  an  animal  nearly  four  times  as  long-,  to  consume  the 
same  quantity  of  oxygen  as  atmospheric  air. 

It  is  speedily  removed,  because,  by  the  deep  inspirations  the  necessary  quantity  of 
oxygen  is  conveyed  into  the  system. 

It  is  accompanied  by  sickness  of  stomacJi,  and  loatldng  of  food,  because,  digestion,  like 
exercise,  demands  a  copious  supply  of  oxygen.  There  are  many  facts  to  prove,  that 
oxygen  is  a  principal  agent  in  digestion  and  assimilation.  The  quantity  employed  in 
these  processes  seems,  in  some  degree,  to  be  regulated  by  the  kind  of  food  used.  An 
animal  diet  consumes  more  than  a  vegetable  one.  Mr.  Spalding  found  that  when  he 
lived  upon  animal  food,  and  drank  spirituous  liquors,  he  expended  the  oxygenous  por- 
tion of  the  atmosphere  in  his  diving  bell,  in  a  much  shorter  time  than  when  he  subsisted 
on  vegetable  matter  and  water.  Dr.  Beddoes  has  also  furnished  some  curious  facts, 
which  go  to  establish  the  same  conclusion. 

It  is  attended  by  excessive  tMrst,  because,  in  a  rare  atmosphere,  there  will,  of  necessity, 
be  a  profuse  evaporation  from  the  surface  of  the  body. 

The  pulsations  of  the  heart  are  more  numerous,  because  they  are  performed  less  vigo- 
rously. 

Not  altogether  dissimilar  in  its  nature,  or  origin,  though  milder  in  its  symptoms,  and 
slower  in  its  occurrence,  is  the  fatigue  occasioned  bv  immoderate  exercise  under  the 
ordinary  constitution  of  the  atmosphere.  In  this  case,  we  observed  an  increased  fre- 
quency of  the  pulse,  and  of  respiration,  &c.  &c.  The  cure,  likewise,  is  by  rest.  Cold 
•water  is  found  more  refreshing  than  spirituous  liquors. 

There  is  another  phenomenon  connected  with  the  present  subject,  which  deserves 
to  be  noticed.  1  allude  to  the  propensity  to  sleep  which  has  already  been  remarked. 
This,  too,  can  only  be  explained  by  ascribing  it  to  a  deficiency  of  oxygen. 

Sleep  is  a  suspension  of  all  or  a  majority  of  the  operations  of  the  mind.  We  have 
not,  it  is  true,  in  our  possession  any  direct  evidence  to  prove  that  the  efiorts  of  the  in- 
tellect, like  those  of  the  body,  exact  a  fixed  and  determinate  quantity  of  oxygen.  We 
had,  indeed,  the  promise  of  some  experiments  to  ascertain  it  by  Lavoisier,  in  an  essay, 
where,  after  indicating  the  expenditure  of  vital  air  by  muscular  exercise,  he  undertakes 
to  show  by  calculation,  "the  quantity  of  mechanical  labour  exerted  by  the  philosopher 
who  refects,  by  the  man  of  letters  who  writes,  or  the  musician  who  composes.'  These 
operations,  he  adds,  though  intellectual,  have  a  certain  dependence  on  the  physical 
and  material  part  of  man,  which  renders  them  susceptible  of  comparison  with  the  la- 
bours of  the  mechanic. 

Whether  these  views  be  just  as  they  are  brilliant,  I  shall  not  pretend  to  decide.  But, 
though  we  may  never  be  competent  to  determine,  with  much  accuracy,  the  quantity  of 
oxygen  consumed  by  the  operations  of  the  mind,  yet,  that  it  is  essentially  necessary  to 
the  exertion  of  the  intellectual  faculties  is  sufficiently  probable. 

With  respect  to  the  influence  of  a  subtraction  of  oxygen  in  the  production  of  sleep, 
a  few  facts  will  be  sufficient  to  attest  it. 

In  the  first  place,  we  know  that  the  primary  operation  of  all  the  irrespirable  gases, 
and  these  contain  no  oxygen,  is  productive  of  heaviness  and  sleep. 

Sleep  is  apt,  moreover,  to  occur  during  the  progress  of  digestion,  when  the  oxygen 
of  the  system  is  employed,  in  a  considerable  degree,  in  the  assimilation  of  aliment,  and 


170 

of  temperature  (Reaumur's  scale;)  solid  bodies  themselves  might  be- 
come fluid.  In  a  word,  a  considerable  diminution  in  the  weight  of  the 
atmosphere  would  have  absolutely  the  same  effect,  as  raising  its  tempera- 
ture to  a  very  great  height,  which,  changing  the  face  of  the  universe, 
would  convert  all  liquids  into  elastic  fluids,  and  would,  doubtless,  melt 
all  solid  bodies. 

The  variations  in  the  weight  of  the  atmosphere,  distinguishable  by  the 
barometer,  are  of  very  little  importance  to  the  physiologist,  and,  I  might 
even  add,  to  the  physician,  notwithstanding  the  minute  attention  with 
which  some  writers  note  the  state  of  the  barometer,  of  the  thermometer, 
and  hygrometer,  and  of  the  electrical  state  of  the  atmosphere,  in  giving 
an  account  of  a  disease,  or  of  an  experiment,  on  which  the  above  circum- 
stances have  no  apparent  or  certain  influence.  The  atmosphere,  like 
every  other  fluid,  has  a  perpetual  tendency  to  a  state  of  equilibrium, 
hence  the  rush  of  air  into  the  lungs,  or  into  other  situations  in  which  its 
quantity  is  diminished,  by  the  combinations  which  it  forms,  or  by  the  ef- 
fects of  heat  which  renders  it  lighter,  by  rarefaction  :  the  same  principle 
explains  the  formation  of  the  trade  and  other  winds. 

The  atmospherical  air  combines  with  water  and  dissolves  it,  as  the  lat- 
ter dissolves  saline  substances.  In  this  consists  the  process  of  evapora- 
tion. The  air  becomes  saturated  with  water,  in  the  same  manner  as  wa- 
ter becomes  saturated  with  salt,  to  such  a  degree,  as  to  be  incapable  of 
holding  a  greater  quantity  in  solution.  As  its  temperature  rises,  its  sol- 
vent power  increases,  and  the  latter  diminishes,  as  it  grows  cold ;  varia- 
tions of  temperature  produce  the  same  effect  on  solutions  of  salts  in  li- 
quids. The  formation  of  all  the  aqueous  meteors,  depends  on  the  differ- 
ent conditions  of  the  solvent  powers  of  the  atmosphere;  when  c  msicler- 
able,  the  atmosphere  is  warm  and  dry,  and  the  air  serene;  clouds  form, 
when  it  is  saturated;  dews,  fogs,  and  rain,  are  the  consequence  of  a  di- 
minution of  its  solvent  power,  as  snow  and  hail,  of  a  degree  of  cold  which 
precipitates  the  fluid.  The  different  degrees  of  dryness  or  moisture, 
marked  by  the  hygrometer,  only  sensibly  affect  the  human  body,  when  it 
has  been  exposed  for  a  considerable  time  to  its  influence. 

Chemically  considered,  the  atmospherical  air,  which  was  long  regard- 
ed as  a  simple  body,  is  composed  of  about  0,27  of  oxygen,  0,73  of  azote, 
and  of  0,01  or  0,02  of  carbonic  acid.  The  proportions  of  oxygen,  ac- 
cording to  Humboldt,  vary  from  0,23  to  0,29;  that  of  azote,  is  almost  al- 
ways the  same;  carbonic  acid  is  the  more  abundant,  as  the  air  is  less 
pure*.  This  part  of  natural  philosophy,  which  is  called  eudiometry,  or 


the  elaboration  of  chyle ;  or,  if  the  disposition  to  sleep  be  counteracted,  the  senses,  at 
least,  become  more  dull,  and  the  understanding  less  acute  and  energetic. 

The  production  of  sleep,  is  favoured,  too,  as  has  been  proved,  by  external  warmth, 
which  lessens  the  supply  of  oxygen. 

It  is  from  the  combination  of  these  causes,  that  among  the  inhabitants  of  hot  climates, 
the  custom  of  sleeping  during  the  day,  and  especially  after  eating1,  unviersally  prevails. 
We  must  acknowledge  that  the  outline  of  this  theory  was  derived  from  the  Lectures  of 
Mr.  Allen,  of  Edinburgh,  on  Physiology.- — Chapman. 

*  Th  s  is  pretty  nearly  the  original  estimate  of  Lavoisier,  whose  experiments  have 
since  been  very  frequently  repeated,  and  with  no  material  difference  in  the  results.  It 
is,  however,  proper  to  recollect,  in  speaking  of  the  relative  proportion  of  the  ingredi- 
ents of  the  atmosphere,  that  this  estimate  must  be  considered  as  having  reference  to 
•weight  and  not  to  measure.  On  this  point  Lavoisier  is  silent,  as  well  as  most  other  che- 
mical writers.  It  is  nevertheless  a  fact,  as  has  been  more  particularly  shxnvn  by  Ber- 


171 

the  measurement  of  the  purity  of  the  air,  is  far  from  accomplishing  what 
its  name  indicates,  and  has  disappointed  the  hopes  which  had  been  en- 
tertained on  the  subject.  Eudiometrical  instruments  can  inform  us,  on- 
ly of  the  proportion  of  oxygen  contained  in  the  atmosphere;  now,  its  sa- 
lubrity, its  fitness  for  respiration,  is  not  in  proportion  to  the  quantity  of 
oxygen.  The  volatilized  remains  of  putrid  animal  or  vegetable  substan- 
ces, various  mephitic  gases,  combine  with  it,  and  affect  its  purity.  In 
the  comparative  analysis  of  air  procured  on  the  Alps  and  in  the  mar- 
shes of  Lombardy,  there  was  found  in  each  the  same  quantity  of  oxygen; 
and  yet,  those  who  breathe  the  former,  enjoy  robust  health,  while  the 
inhabitants  of  the  marshy  plains  of  Lombardy  are  carried  off  by  epidemic 
diseases,  are  pale,  emaciated,  and  habitually  lead  a  languid  existence. 

Though,  at  least,  0,20  of  oxygen  are  necessary  to  render  the  air  fit  for 
respiration,  the  proportion  may  be  diminished  to  seven  or  eight  parts  in 
the  hundred  ;  but  in  such  cases,  the  breathing  is  laborious,  panting,  and 
attended  with  a  sense  of  suffocation,  in  short,  asphyxia  comes  on,  even 
while  the  air  stil!  contains  a  certain  quantity  of  oxygen,  of  which  the  lungs 
cannot  entirely  deprive  it.  Whenever  a  number  of  persons  are  collected 
in  a  confined  place,  in  which  the  air  cannot  be  easily  renewed,  the  quan- 
tity of  oxygen  diminishes  rapidly,  that  of  carbonic  acid  increases.  The 
latter,  in  consequence  of  hs  specific  gravity,  sinks  to  the  lowest  part,  and 
strikes  with  death  every  living  being  which  it  envelopes.  When  two 
lighted  candles,  of  different  lengths,  are  placed  under  the  same  bell,  the 
shorter  candle  goes  out  first,  because  the  carbonic  acid  formed  during 
combustion,  sinks  to  the  most  depending  part.  For  the  same  reason,  the 
pit  is  the  most  unhealthy  part  of  a  play-house,  when  a  great  number  of 
people  after  remaining  in  it  for  several  hours,  have  deprived  the  air  of  a 
cousiderable  portion  of  its  oxygen. 

Persons  collected  together,  and  enclosed  in  a  small  space,  injure  each 
other,  not  only  by  depriving  the  atmosphere  of  its  respirable  element,  but 
particularly  by  altering  its  composition,  by  the  combination  of  all  the  sub- 
stances exhaled  from  their  bodies.  These  volatilized  animal  emanations, 
become  putrid,  while  in  the  atmosphere,  and  conveyed  to  the  lungs  dur- 
ring  respiration, becomes  the  germ  of  the  most  fatal  diseases.  It  is  in  this 
manner,  that  the  jail  and  hospital  fevers  so  fatal  to  almost  all  whom  it  at- 
tacks, arises  and  spreads.  A  dry  and  temperate  air  containing  0.27  of 
oxygen  and  0.73  of  azote,  and  free  of  other  gases,  or  other  volatilized 
substances,  is  the  fittest  for  respiration.  In  certain  cases  of  disease,  how- 
ever, this  function  is  most  freely  performed  in  a  less  pure  air.  Thus, 
patients  labouring  under  pulmonary  consumption,  prefer  the  thick  and 
damp  air  of  low  situations,  to  the  sharp  and  dry  air  of  mountains;  nerv- 
ous women  prefer  that  in  which  horn,  feathers,  or  other  animal  substances 
are  burning.  An  atmosphere  highly  electrical,  at  the  approach  of  a  storm, 
renders  respiration  very  laborious,  in  some  cases  of  asthma.  In  short, 


thollet,  that  the  atmosphere  contains  only  twenty-two  parts  of  oxygen,  in  the  hundred, 
by  measure. 

By  some  chemists  it  has  been  supposed,  from  the  circumstance  of  the  carbonic  acid 
being  generally  found  in  a  larger  quantity  near  the  earth,  that  it  is  an  accidental,  and 
not  an  essential  constituent  of  the  atmosphere.  But  by  De  Saussure  it  was  detected  in 
the  air,  on  the  summit  of  Mont  Blanc  ;  and  from  this,  and  a  variety  of  other  considera- 
tions, it  would  appear  to  be  a  uniform  part  of  atmospheric  air,  existing  most  probably 
in  a  state  of  chemical  combination. —  Chapman. 


172 

the  qualities  of  the  air  must  be  suited  to  the  condition  of   the  vita! 
power  in  the  lungs,  as  those  of  the  food,  to  the  sensibility  of  the  stomach. 

Being  obliged,  on  this  subject,  to  content  myself  with  the  ungracious 
office  of  compiler,  I  hasten  to  bring  this  article  to  a  close,  and  to  refer  the 
reader  for  a  fuller  account  of  the  air,  considered  in  its  physical  and 
chemical  relations,  to  the  works  of  M.  M.  Fourcroy,  Hauy,  Brisson,  Sec. 
to  that  of  M.  Guyton  Morveau,  on  the  method  of  purifying  the  air,  when 
from  different  combinations,  it  becomes  unfit  for  respiration. 

LXXI.  In  man  and  in  all  warm-blooded  animals,  with  a  heart  contain- 
ing two  auricles  and  two  ventricles,  the  blood  which  has  been  conveyed 
to  all  the  organs  by  the  arteries,  and  which  has  been  brought  back,  by  the 
veins,  to  the  heart,  cannot  return  to  it,  without  having  previously  passed 
through  the  lungs,  which  are  viscera  destined  to  the  transmission  of  air; 
of  a  spongy  texture,  and  through  which  the  blood  must,  of  necessity  cir- 
culate to  get  from  the  right  to  the  left  cavities  of  the  heart.  This  course  of 
the  blood  constitutes  the  pulmonary  or  lesser  circulation:  it  does  not  exist 
in  some  cold-blooded  animals.  In  reptiles,  for  instance,  the  heart  has 
but  one  auricle  and  one  ventricle ;  the  pulmonary  artery  in  them,  arises 
from  the  aorta,  and  conveys  but  a  small  proportion  of  the  blood  ;  hence 
the  habitual  temperature  of  these  animals  is  much  lower  than  that  of 
man.  For  the  same  reason  too,  there  exist  so  small  a  difference,  be- 
tween their  venous  and  arterial  blood;  the  quantity  of  fluid  vivified  by 
exposure  to  the  air,  in  the  pulmonary  tissue,  being  too  small  to  effect,  by 
its  union  with  the  general  mass,  a  material  change  on  its  qualities. 

Mayow  has  given  the  most  accurate  notion  of  the  respiratory  organ, 
by  comparing  it  to  a  pair  of  bellows,  containing  an  empty  bladder,  the 
neck  of  which  by  being  adapted  to  that  of  the  bellows,  should  admit  air 
on  drawing  asunder  its  sides.  The  air,  in  fact,  enters  the  lungs,  only 
when  the  chest  dilates  and  enlarges,  by  the  separation  of  its  parietes, 
agents  of  respiration  are,  therefore,  the  muscles  which  move  the  parietes 
of  the  chest,  these  are  formed  of  osseous  and  soft  parts,  in  such  a  man- 
ner, as  to  possess  a  solidity  proportioned  to  the  importance  of  the  organs 
which  the  chest  contains,  besides  a  capacity  of  motion  required  to  carry 
on  the  functions  intrusted  to  them.* 

To  carry  on  respiration  which  may  be  defined  the  alternate  ingress  of 
air  into  the  lungs,  and  its  egress  from  those  organs,  it  is  necessary  that 
the  dimensions  of  the  chest  should  be  enlarged  (this  active  dilatation  of 
the  cavity  of  the  chest  is  called  inspiration,)  and  that  it  should  contract  to 
expel  the  air  which  it  had  received  during  the  first  process.  This  se- 
cond action  is  called  expiration,  it  is  always  of  shorter  duration  than  the 
former,  its  agents  are  more  mechanical,  and  the  muscles  have  much  less 
influence  upon  it. 

The  parietes  of  the  chest  are  formed,  at  the  back  part,  by  the  verte- 
bral column,  at  the  fore  part  by  the  sternum,  and  on  the  sides  by  the 
ribs,  which  are  osseo  cartilaginous  arches,  situated  oblique  between 
the  vertebral  column,  which  is  fixed  and  becomes  the  point  of  support  of 
their  motions,  and  the  sternum  which  is  somewhat  moveable — the  spaces 
between  the  ribs  are  filled  by  muscular  planes  of  inconsiderable  thick- 
ness, the  internal  and  external  intercostal  muscles,  the  fibres  of  which 

*  See  APPENDIX,  Note  U,  for  remarks  on  the  mechanism  of  the  respiratory 
organs. 


173 

lie  in  opposite  directions. — Besides,  several  muscles  cover  the  outer  part 
of  the  thorax,  and  pass  from  the  ribs  to  the  neighbouring  bones  ;  as  the 
subclavian  muscles,  the  great  and  lesser  pectorals,  the  serrati,  the  lastissi- 
mi  dorsi,  the  scaleni,  the  longissimi  dorsi,  the  sacro  lumbales,  and  the 
serrati  minores,  posterior,  superior,  and  inferior.  But  of  all  the  mus- 
cles which  form  the  anterior,  posterior,  and  lateral  parietes  of  the  chest, 
the  most  important  is  the  diaphragm,  a  fleshy  and  tendinous  partition,  ly- 
ing horizontally  between  the  chest  and  the  abdomen,  which  it  separates 
from  each  other  ;  it  is  attached  to  the  cartilages  of  the  false  ribs,  and  to 
the  lumbar  vertebrae,  and  has  three  openings  to  transmit  the  oesophagus 
and  the  vessels  which  pass  from  the  abdomen  to  the  chest,  or  from  the 
latter  into  the  abdomen. 

In  health  the  chest  dilates  only  by  the  descent  of  the  diaphragm.  The 
curved  fibres  of  that  muscle  straightened  in  contraction,  descend  towards 
the  abdomen,  and  compress  the  viscera.  The  descent  of  the  viscera 
thrusts  forward  the  interior  parietes  of  that  cavity,  and  these  recede, 
when  on  expiration  taking  place  after  inspiration,  the  diaphragm  now  re- 
laxed, rises,  pressed  upwards  by  the  abdominal  viscera,  compressed  them- 
selves by  the  large  muscles  of  the  abdomen.  But  when  it  is  necessary  to 
take  into  the  chest  a  great  quantity  of  air,  it  is  not  sufficient  that  it  should 
be  enlarged  merely  by  the  descent  of  the  diaphragm — it  is  required  be- 
sides, that  its  dimensions  should  be  increased  in  every  direction.  The  inter- 
costal muscles  then  contract,  and  tend  to  bring  together  the  ribs  between 
which  they  are  situated.  The  intercostal  spaces,  however  become  wider, 
especially  at  their  anterior  part,  for,  whenever  lines  falling  pbliquelyona 
vertical  line,  change  their  direction,  approaching  to  a  right  angle,  the  in- 
termediate spaces  receive  the  greater  increase,  as  the  lines,  more  oblique 
at  first,  become  at  last  more  nearly  horizontal.  Besides,  as  the  ribs  are 
curved  in  the  course  of  their  length,  in  two  directions,  and  both  the  di- 
rection of  their  faces,  and  edgewise,  the  convexity  of  the  first  curvature  is 
outwards,  the  ribs  recede  to  a  distance  from  the  axis  of  the  chest,  whose 
cavity  is  enlarged  transversely,  while  the  second  curvature  (in  the  direc- 
tion of  their  edge)  being  increased  by  a  real  twisting  of  these  bones,  and 
which  reaches  to  the  cartilaginous  parts,  the  sternum  is  heaved  forward 
and  upward,  so  that  the  posterior  extremity  of  the  ribs  is  removed  from 
their  sternal  end.  But  as  the  ribs  are  not  all  equally  moveable,  as  the 
first  is  almost  always  invariably  fixed,  and  as  the  others  are  moveable  in 
proportion  to  their  length,  the  sternum  is  tilted  in  such  a  way  that  the 
lowermost  extremity  is  thrust  forward*.  The  diameter  of  the  chest  from 
the  fore  to  the  back  part  increases,  therefore,  as  well  as  the  transverse 
diameter.  This  increase  of  dimensions  has  been  estimated  at  two 
inches,  to  each  of  these  diameters;  the  dimensions  of  the  vertical  dia- 
meter, which  are  regulated  by  the  depression  of  the  diaphragm,  are  much 
greater. 

LXXII.  Professor  Sabatier,  in  his  memoir  on  the  motion  of  the  ribs, 
and  on  the  action  of  the  intercostal  muscles,  maintains  that  during  the 


*  The  opinion  originally  advanced  by  Haller,  of  the  immobility  of  the  first  rib,  has 
been  very  properly  contested  by  Magendie,  (Precis.  Elem.)  In  certain  states  of  dis- 
ease where  FORCED  inspirations  are  frequently  made,  we  can  readily  satisfy  ourselves 
that  the  upper  part  of  the  chest  is  very  freely  dilated  by  the  action  of  the  scaleni  ser- 
rati, &c.  In  asthma  we  have  repeatedly  had  occasion  to  remark  this  mobility. — 
Godman. 


174 

action  of  inspiration,  the  upper  ribs  alone  rise,  that  the  lower  ribs  descend 
and  slightly  close  on  the  chest,  while  the  middle  ribs  project  outwardly, 
and  that  in  expiration,  the  former  set  of  ribs  descend,  that  the  latter  start 
a  little  outwardly,  and  that  the  middle  set  encroach  on  the  cavity  of  the 
chest.  The  learned  Professor  adds,  that  the  cartilaginous  articulating 
surfaces,  by  which  the  ribs  are  connected  to  the  transverse  processes  of 
the  vertebrae,  appear  to  him  to  favour  these  different  motions,  as  the  di- 
rection of  the  articulations  of  the  upper  ribs,  is  upward,  and  that  of  the  low- 
er downward;  but  on  considering  the  subject  with  attention,  it  will  be 
seen,  that  the  surfaces  by  which  the  transverse  processes  of  the  verte- 
brae are  articulated  to  the  tuberosities  of  the  ribs,  are  turned  directly  for- 
ward in  the  greatest  number,  some  of  the  lower  ribs  are,  at  the  same 
time,  directed  slightly  upward.  If  we  examine  the  action  of  the  bones 
of  the  chest,  during  inspiration,  in  a  very  thin  person,  for  example,  in 
phthisical  patients,  whose  bones  are  covered  with  little  else  than  skin,  we 
shall  find,  that  all  the  ribs  rise,  and  are  carried  somewhat  outwardly.  It 
is  not  easy  to  conceive  how  the  intercostal  muscles,  which  Professor  Sa- 
batier  considers  as  the  agents  of  respiration,  should  elevate  the  upper 
ribs  and  depress  the  lower.  The  diaphragm,  whose  circumference  is  in- 
serted in  the  latter,  might,  by  its  contraction,  produce  this  effect;  but  as 
the  intercostals  have  their  fixed  point  of  action  in  the  upper  ribs,  they 
oppose  and  neutralize  this  effort,  and  all  the  ribs  are  elevated  at  once. 
If  this  were  not  the  case,  the  ribs  ought  to  be  depressed,  whenever  the 
intercostals  contract,  since  the  lowermost,  fixed  by  the  diaphragm,  would 
become  the  §x«d  point  on  which  all  others  should  move. 

As  the  fibres  of  the  external  and  internal  intercostal  muscles,  are  in  di- 
rect opposition  to  each  other,  those  of  the  former  set  of  muscles  having 
an  oblique  direction,  from  above  downward,  and  from  behind  forward, 
and  crossing  the  fibres  of  the  other  set  whose  obliquity  is  in  a  different  di- 
rection ;  several  physiologists  have  thought,  that  these  muscles  were  op- 
posed to  each  other,  that  the  internal  intercostal  muscles  brought  toge- 
ther the  ribs,  after  they  had  been  separated  by  the  external  intercostals, 
the  one  set  being  muscles  of  expiration,  while  the  other  set  contracted 
during  inspiration. 

It  is  well  known  with  what  pertinacity,  Hamberger,  in  other  respects, 
a  physiologist  of  considerable  merit,  defended  this  erroneous  opinion,  in 
his  dispute  with  Haller;  it  is  now,  however,  ascertained,  that  all  the  in- 
tercostal muscles  concur  in  dilating  the  chest,  and  that  they  ought  to  be 
ranked  among  the  agents  of  inspiration,  because  the  unequal  capacity  of 
motion  in  the  ribs,  prevents  the  internal  intercostals,  the  lower  insertion 
of  which  is  nearer  to  the  articulation  of  these  bones  to  the  vertebrae,  from 
depressing  the  upper  ribs.  Of  the  very  conclusive  experiments,by  which 
Haller  undertook  to  refute  the  arguments  of  his  adversary,  I  shall  relate 
only  that  which  is  performed  by  stripping  the  parietes  of  the  chest,  in  a 
living  animal,  of  all  the  muscles  which  cover  it,  and  by  removing,  in  dif- 
ferent pails  of  the  thorax,  some  of  the  external  intercostal  muscles.  The 
internal  intercostals  are  then  seen  to  contract  during  inspiration,  toge- 
ther with  the  remaining  external  intercostals.  These  muscles,  therefore, 
have  a  common  action,  and  are  not  in  opposition  to  each  other.  The 
same  experiment  serves  to  prove  the  increased  dimensions  of  the  space 
between  the  ribs.  On  holding  one's  finger  between  two  of  the  ribs,  it 
feels  less  confined,  when  during  inspiration,  these  bones  rise  and  thrust 
forward  the  sternum. 


175 

This  question  being  at  rest,  although  in  pursuit  of  science  one  should 
inquire  how  things  are  effected,  and  not,  wherefore  they  come  to  pass,  one 
feels  naturally  desirous  to  know  what  purpose  is  answered  by  the  different 
direction  of  the  fibres  of  the  two  sets  of  intercostal  muscles;  and  with 
what  view  Nature  has  departed  from  her  wonted  simplicity,  in  giving  to 
their  fibres  opposite  directions.  In  answer  to  this,  one  may  observe,  that 
the  action  of  powers  applied  obliquely  to  a  lever,  being  decomposed  in 
consequence  of  that  obliquity,  a  part  of  the  action  of  the  external  inter- 
costals  would  tend  to  draw  the  ribs  towards  the  vertebral  column,  which 
could  not  happen,  without  forcing  back  the  sternum,  if  the  internal  inter- 
costals  did  not  tend  to  bring  forward  the  ribs,  at  the  same  time  that  they 
elevate  them;  so  that  these  two  muscular  planes,  united  in  their  action 
of  raising  the  ribs,  antagonise  and  reciprocally  neutralize  each  other,  in 
the  effort  by  which  they  tend  to  draw  them  in  different  directions. 

To  this  advantage  of  mutually  correcting  the  effects  that  would  result 
from  their  respective  obliquity,  may  be  added  the  benefit  arising  from  a 
texture  capable  of  a  greater  resistance  ;  it  is  clearly  obvious,  that  a  tissue 
whose  threads  cross  each  other,  is  firmer  than  one  in  which  ail  the 
threads  merely  in  juxta  position,  or  united  by  means  of  another  substance, 
should  all  lie  in  the  same  direction.  Hence,  Nature  has  adopted  this 
arrangement,  in  the  formation  of  the  muscular  planes  constituting  the 
anterior  and  lateral  parietes  of  the  abdomen,  without  which  the  abdomi- 
nal viscera  would  frequently  have  formed  herinary  tumours,  by  sepa- 
rating the  fibres  and  getting  engaged  between  them.  In  this  respect, one 
may  compare  the  tissue  of  the  abdominal  parietes,  in  which  the  fibres  of 
the  external  and  internal  oblique  muscles,  which  cross  each  other,  are 
themselves  crossed  by  the  fibres  of  the  transversales,  to  the  tissue  of  those 
stuffs  whose  threads  cross  each  other,  or  rather  to  wicker  work,  to  which 
basket-makers  give  so  much  strength,  by  interweaving  the  osier  in  a  va- 
riety of  directions. 

LXXIII.  When  from  any  cause,  respiration  becomes  difficult,  and  the 
diaphragm  is  prevented  from  descending  towards  the  abdomen,  or  the 
motion  of  inspiration  is  impeded,  in  any  way,  the  intercostals  are  not  alone 
employed  in  dilating  the  chest,  but  are  assisted  by  several  other  auxiliary 
muscles;  the  scaleni,  thesubclavii,  the  pectorales,  the  serrati  inagni,  and 
the  latissimi  dorsi,  by  contracting,  elevate  the  ribs,  and  increase,  in  more 
directions  than  one,  the  diameter  of  the  chest.  The  fixed  point  of  these 
muscles,  then,  becomes  their  moveable  point,  the  cervical  column,  the 
clavicle,  the  scapula,  and  the  humerus,  being  kept  fixed  by  other  powers, 
which  it  is  unnecessary  to  enumerate.  Whoever  witnesses  a  fit  of  con- 
vulsive asthma,  or  of  a  suffocating  cough,  will  readily  understand  the  im- 
portance and  action  of  these  auxiliary  muscles. 

Inspiration  is  truly  a  state  of  action,  an  effort  of  contractile  organs, 
which  must  cease  when  these  are  relaxed.  The  expiration  which  follows 
is  passive,  and  assisted  by  very  few  muscles,  and  depends  chiefly  on  the 
re-action  of  the  elastic  parts  entering  into  the  structure  of  the  parietes 
of  the  chest.  We  have  seen,  that  the  cartilages  of  the  ribs  are  pretty 
considerably  twisted,  so  as  to  carry  outward  and  downward  their  upper 
edge :  when  the  cause  which  occasions  this  twisting  ceases  to  act,  these 
parts  return  to  their  natural  condition,  and  bring  back  the  sternum  to- 
wards the  vertebral  column,  towards  which  the  ribs  descend,  from  their 
weight.  The  diaphragm  is  forced  towards  the  chest,  by  the  abdominal 
viscera,  which  are  compressed  by  the  broad  muscles  of  the  abdomen. 


176 

i 

In  every  effort  of  expiration,  as  in  cough  and  vomiting,  these  muscles 
re-act,  not  merely  by  their  own  elasticity,  but  they  besides  contract  and 
tend  to  approach  towards  the  vertebral  column,  by  pressing  upwards  the 
abdominal  viscera  towards  the  chest.  The  triangularis  sterni,  the  sub- 
costales,  and  the  serratus  inferior  pasticus,  may  likewise  be  ranked  among 
the  agents  of  expiration;  but  they  appear  to  be  seldom  employed,  and  to 
be  too  slender  and  weak  to  contribute  much  to  the  contraction  of  the 
chest. 

LXXIV.  When  the  chest  enlarges,  the  lungs  dilate  and  follow  its  pa- 
rietes,  as  these  recede  from  each  other.  These  two  viscera,  soft,  spon- 
gy, and  of  less  specific  gravity  than  water,  covered  by  the  pleura  which 
is  reflected  over  them,  are  always  in  contact  with  the  portion  of  that 
membrane  which  lines  the  cavity  of  the  thorax;  no  air  is  interposed  be- 
tween their  surfaces  (which  are  habitually  moistened  by  a  serous  fluid 
exuding  from  the  pleura)  and  that  membrane,  as  may  be  seen,  by  open- 
ing, under  water,  the  body  of  a  living  animal,  when  no  air  will  be  seen  to 
escape.  As  the  lungs  dilate,  their  vessels  expand,  and  the  blood  circu- 
lates through  them  more  freely;  the  air  contained  in  the  innumerable 
cells  of  their  tissue,  becomes  rarefied,  in  proportion  as  the  space  in  which 
it  is  contained  is  enlarged.  Besides,  the  warmth  communicated  to  it  by 
the  surrounding  parts,  enables  it,  in  a  very  imperfect  manner,  to  resist 
the  pressure  of  the  atmosphere,  rushing  through  the  nostrils  and  mouth 
into  the  lungs,  by  the  opening  in  the  larynx  which  is  always  pervious,  ex- 
cept during  deglutition. 

LXXV.  The  pulmonary  tissue  into  which  the  air  is  thus  drawn  in, 
every  time  the  capacity  of  the  chest  is  increased,  does  not  consist  mere- 
ly of  air-vessels,  which  are  but  branches,  of  different  sizes,  of  the  two 
principal  divisions  of  the  trachea,  but  is  formed,  likewise,  by  the  lobular 
tissue  into  which  these  canals  deposit  the  air;  it  contains  also  a  great 
quantity  of  lymphatics  and  blood-vessels,  of  glands  and  nerves.  Cellu- 
lar tissue  unites  together  all  these  parts,  and  forms  them  into  two  masses 
covered  over  by  the  pleura,  and  of  nearly  the  same  bulk*;  suspended  in 
the  chest  from  the  bronchia  and  trachea,  and  every  where  in  contact 
"with  the  parietes  of  the  cavities  of  the  chest,  except  towards  their  root, 
at  which  they  receive  all  their  nerves  and  vessels. 

The  pulmonary  artery  arises  from  the  base  of  the  right  ventricle,  and 
divides  into  two  arteries,  one  to  each  lung.  On  reaching  the  substance 
of  these  viscera,  these  vessels  divide  into  as  many  branches  as  there  are 
principal  lobes.  From  these  branches,  there  arise  others,  which  again 
subdivide  into  lesser  ones,  until  they  become  capillary,  and  continuous 
with  the  radicles  of  the  pulmonary  veins. 

These  vessels,  formed  from  the  extremities  of  the  artery,  unite  into 
trunks,  which  progressively  enlarging,  emerge  from  the  lungs,  and  open, 
four  in  number,  inio  the  left  auricle.  Besides  these  large  vessels,  by 
means  of  which,  the  cavities  in  both  sides  of  the  heart  communicate  to- 
gether, the  lungs  receive  from  the  aorta  two  or  three  arteries,  called  bron- 
chial arteries,  these  penetrate  into  their  tissue,  and  follow  the  direction 
of  the  other  vessels,  and  terminate  in  the  bronchial  veins,  which  open  in 
the  superior  cava,  not  far  from  its  termination  into  the  right  auricle.-— 
These  bronchial  vessels  are  sufficient  for  the  nourishment  of  the  pulmo- 

*  It  is  well  known  that  the  right  lung  is  larger  than  the  left,  that  it  is  divided  into 
three  principal  lobes,  while  the  latter  has  only  two. — Jiuthm's  J\"ote. 


177 

mry  organ,  which,  in  reality,  is  not  near  so  bulky  as  it  appears,  as  may 
be  ascertained  by  examining  the  lungs,  after  all  the  air  has  been  extract- 
ed from  them,  by  means  of  an  air  pump,  applied  to  the  trachea. 

Physiologists,  for  the  most  part,  consider  the  bronchial  arteries  as  the 
nutritious  vessels  of  the  lungs.  They  assert,  that  as  the  blood  which  flows 
along  the  branches  of  the  pulmonary  artery  resembles  venous  blood,  it 
is  unfit  for  the  nutrition  of  the  lungs,  and  that  it  was  necessary  that  these 
organs  should  be  supplied  by  arteries  arising  from  the  aorta,  and  contain- 
ing- blood  analogous  to  that  which  is  sent  to  every  part  of  the  body.  But 
though  it  be  admitted,  that  this  venous  blood,  brought  from  every  part  of 
the  body,  and  sent  into  the  lungs,  by  their  principal  artery,  may  not  be 
tit  to  maintain  the  organ  in  its  natural  economy,  this  blood  is' fit  for  that 
use,  when,  after  being  made  hot,  spumous,  and  florid,  by  the  absorption 
of  the  atmospherical  oxygen,  it  returns  by  the  pulmonary  veins,  into  the 
left  cavities  of  the  heart*. 

Some  have  thought,  that  the  blood  which  flows  in  the  bronchial  vessels, 
exposed  to  the  action  of  the  air, ''like  the  portion  of  this  fluid  which  tra- 
verses the  pulmonary  system,  Idst  nothing  of  its  arterial  qualities,  and 
that,  poured  by  the  bronchial  veins  into  the  superior  or  descending  vena 
cava,  it  was  a  necessary  stimulus  for  the  right  cavities  of  the  heart,  of 
which  blood  entirely  dark  and  venous,  would  not  have  awakened  the  con- 
tractility. But  even,  if  the  experiments  of  Goodwin  had  not  proved, 
that  the  parietes  of  these  cavities  have  a  sensibility  relative  to  dark  blood, 
by  virtue  of  which,  this  stimulus  is  sufficient  to  determine  their  contrac- 
tion, the  action  of  the  heart  does  not  depend  as  closely  as  has  been  said, 
on  the  impression  of  the  blood  on  its  substance,  since  it  contracts,  though 
empty,  and  prolongs  its  contractions  to  relieve  itself  of  the  black  blood 
which  fills  it,  when  an  animal  dies  of  asphyxia. 

Boerhaave,  who  admitted  one  sort  of  peripneumony  depending  on  the 
obstruction  of  the  bronchial  vessels,  whilst  another,  according  to  the  same 
writer,  depends  on  the  obstruction  of  the  pulmonary  vessels,  seems  to 
justify,  in  some  measure,  the  reproach,  exaggerated  unquestionably, 
which  some  authors  have  thrown  out  against  anatomy,  of  having  rather 
retarded  than  accelerated  the  progress  of  the  Hippocratic  practice  of 
medicine.  The  anatomical  analysis  of  the  lungs,  or  the  distinction  of  the 
tissues  which  enter  into  their  composition,  furnishes  juster  ideas  on  the 
difference  of  the  inflammations  by  which  they  may  be  attacked.  It  has 


*  That  the  bronchial  vessels  exclusively  nourish  the  lungs,  is  an  opinion  entertained 
certainly  by  a  majority  of  physiologists.  When,  however,  we  compare  the  size  of  these 
vessels  with  the  magnitude  of  the  office  assigned  to  them,  it  seems  very  doubtful  whe- 
ther they  are  adequate  to  it.  We  are  inclined  to  believe  notwithstanding  what  is  al- 
leged ag-ainst  it,  that  the  pulmonary  arteries  also  contribute  to  the  nourishment  of  the 
lungs;  and  indeed  there  is  a  fact  which  almost  proves  it.  We  allude  to  the  circum- 
stance of  the  pulmonary  adhesions,  which  are  supposed  to  take  place  in  consequence 
of  inflammation,  having  been  repeatedly  injected  from  the  trunk  of  the  pulmonary  ar- 
teries.—  Chapman. 

The  circumstance  mentioned  at  the  conclusion  of  the  preceding  note,  by  no  means 
settles  the  dispute.  We  can  throw  coloured  water  or  mercury  into  the  trachea,  and  it 
will  flow  into  the  pulmonary  arteries,  pulmonary  veins,  and  bronchial  arteries.  Should 
the  material  be  thrown  into  the  pulmonary  artery,  it  will  enter  the  pulmonary  veins, 
the  bronchise  and  trachea.  If  it  is  thrown  into  the  pulmonary  vein,  it  penetrates  the 
bronchiis,  and  pulmonary  arteries.  Considering-  the  character  of  the  membrane  which 
forms  the  texture  of  these  organs,  we  cannot  see  any  difficulty  in  believing-  the  bron. 
chial  arteries  sufficiently  larg-e  to  nourish  the  lungs. — Godman. 

z 


178  r%jT 

been  seen,  that  of  these  pulmonary  phlegmasise,  the  commonest  and  least 
serious  catarrh  consists  in  inflammation  of  the  mucous  membrane  which 
lines  the  air  passages,  whilst  the  real  peripneumony  has  its  seat  in  the 
parenchyma  of  the  organ,  which  it  converts  into  a  hard  and  compact 
mass.  It  is  this  state  that  anatomists  have  long  designed  under  the  nam.c 
of  hepatization,  because,  in  fact,  the  substance  of  the  lung  has  acquired 
the  hardness,  the  weight,  and  something  of  the  appearance  of  the  liver. 
The  same  anatomical  researches  have  shown  that  pleurisy  consists  in 
inflammation  of  the  pleura,  and  of  the  surface  of  the  lung,  an  inflamma- 
tion which  sometimes  leaves  no  trace,  but  which  oftener  exhibits,  on  the 
opening  of  bodies,  the  pleura  thickened  and  opaque,  covered  with  a  layer 
of  coagulabie  lymph,  whitish,  more  or  less  thick,  or  even  adhering  to 
the  lung*. 

There  arise  from  the  surface,  and  from  the  internal  substance  of  the 
lungs,  a  prodigious  number  of  absorbents,  which  may  be  divided  into 
superficial  and  deep  seated.  The  latter  accompany  the  bronchial  tubes, 
and  penetrate  into  the  substance  of  th&  glandular  bodies  situated  where 
those  air-vessels  divide,  but  collected,  in  greatest  number,  towards  the 
root  of  the  lungs  and  at  the  angle  formed  by  the  bifurcation  of  the  tra- 
chea. These  bronchial  glands,  belonging  to  the  lymphatic  system,  do 
not  differ  from  the  glands  of  the  same  kind,  and  are  remarkably  only  by 
their  number,  the  size,  and  their  habitually  darkish  colour.  The  absorb- 
ents of  the  lungs,  after  ramifying  in  these  glands,  terminate  in  the  upper 
part  of  the  thoracic  duct,  at  the  distance  of  a  few  inches  from  its  termi- 
nation into  the  subclavian  vein.  Lastly,  the  lungs,  though  endowed  with 
a  very  imperfect  degree  of  sensibility,  have  a  considerable  number  of 
nerves  furnished  by  the  great  sympathetic,  and  especially  by  the  eighth 
pair. 

It  was  long  believed,  on  the  authority  of  Willis  that  the  aerial  tissue 
of  the  lungs  is  vesicular,  that  each  ramification  of  the  bronchise  termi- 
nated in  their  substance,  in  the  form  of  a  small  ampullula;  but  at  pre- 
sent, most  anatomists  adopt  the  opinion  of  Helvetius.  According  to 
Helvetius,  every  air-vessel  terminates  in  a  small  lobe,  or  kind  of  sponge 
fitted  for  the  reception  of  air,  and  formed  of  number  of  cells  communi- 
cating together.— These  lobes,  united  by  cellular  tissue,  form  larger 
lobe-s,  and  these  together  form  the  mass  of  the  lungs. 

The  tissue  that  connects  together  the  different  lobes  is  very  different 


*  These  adhesions  of  the  lung  to  the  pleura  costalis,  are  so,  common,  that  the  old 
anatomists  considered  them  as  a  natural  disposition,  and  called  them  ligaments  of  the 
Jungs.  It  has  been  believed  till  now,  that  these  adhesions  arose  from  the  organization 
of  a  substance  transuding  from  the  two  surfaces.  Numerous  dissections  have  con- 
vinced me,  that  in  all  the  points  where  they  are  met  with,  the  pleura  has  disappeared, 
that  it  is  decomposed,  and  that,  whether  it  he  at  the  surface  of  the  lungs,  or  within 
the  ribs  and  the  muscles,  it  is  produced  by  the  act  of  inflammation,  that  it  is  become 
cellular,  by  the  thinning  of  its  tissue  and  the  separation  of  its  lamina.  The  pleura 
thus  reduced  to  cellular  tissue,  the  adhesion  is  produced  by  the  first  intention,  in  the 
same  way  as  in  simple  wounds  immediately  united.  There  is  no  organ  that  abounds 
more  than  the  lungs  in  facts  important  to  morbid  anatomy.  The  variety  of  appearances 
they  exhibit,  on  the  opening  of  bodies,  are  almost  innumerable;  and  to  give  one  in- 
stance, the  pleura  appears  after  pleurisy  in  five  perfectly  distinct  conditions.  1st.  In  its 
natural  state,  when  the  disease  being  incipient  and  slight,  the  resolution  is  effected  at 
the  moment  of  death.— 2dly.  When  it  is  red,  thickened,  and  opake. — 3dly.  When  it 
is  covered  with  coagulabie  "lymph.—  4th ly.  When  it  adheres. — Sthly.  When,  in  conse- 
quence of  chronic  inflammation,  hydrothorax  has  taken  place,  &c.  &c. — Author's  Note. 


179 

from  that  in  which  the  ramifications  of  the  bronchiae  terminate;  air  never 
penetrates  in  it,  except  when  the  tissue  of  the  air  cells  is  ruptured.  On 
such  occasions,  which  are  not  of  rare  occurrence,  on  account  of  the  ex- 
cessive thinness  of  the  lamina  of  the  air  cells  of  that  tissue,  the  lung 
loses  its  form,  and  becomes  emphysematous.  Haller  estimates  at  about 
the  thousandth  part  of  an  inch,  the  thickness  of  the  parietes  of  the  air 
cells,  and  as  the  extreme  ramifications  of  the  plilmonary  vessels  are  dis- 
tributed on  these  parieres,  the  blood  is  almost  in  immediate  contact  with 
the  air.  There  can  be  no  doubt,  that  the  oxygen  of  the  atmosphere  acts 
on  the  blood,  under  such  circumstances,  since  it  alters  its  qualities,  and 
communicates  to  it  a  florid  red  colour,  when  enclosed  in  a  pig's  bladder, 
and  placed  under  a  vesr.el  filled  with  oxygen  gas. 

LXXVI.  Every  time  the  chest  dilates,  in  an  adult,  there  enter  into 
the  lungs,  between  thirty  and  forty  cubic  inches  of  atmospherical  air*, 
consisting,  when  pure,  of  seventy-three  parts  of  azote,  twenty-seven  of 
oxygen,  und  one  or  two  parts  in  the  hundred,  of  carbonic  acidf. 

When  the  air  has  been  exposed,  for  a  few  moments,  in  the  pulmonary 
tissue,  it  is  expelled  by  the  effort  of  expiration,  but  it  is  diminished  in 
quantity,  and  is  reduced  to  thirty-eight  inches.  Its  composition  is  no 
longer  the  same:  it  contains,  it  is  true,  0,79  of  azote;  but  the  vital  portion 
fit  for  respiration,  the  oxygen,  has  undergone  a  great  diminution,  its 
proportion  is  only  0,14:  carbonic  acid  forms  the  remaining  seven  hun- 
dreths,  and  there  are  sometimes  found  one  or  two  pars  of  hydrogen.  It 
is  besides  affected  by  the  addition  of  an  aqueous  vapour,  which  is  condensed 
in  cold  weather,  as  it  escapes  at  the  mouth  and  nostrils.  It  is  called  the 
humour  of  the  pulmonary  transpiration.  These  changes,  compared  to 
those  which  the  blood  experiences  in  passing  though  the  lungs,  clearly 
show  a  reciprocal  action  of  this  fluid  and  of  the  oxygen  of  the  atmosphere. 
The  dark  venous  blood  which  coagulates  slowly,  and  which  then  disen- 
gages a  considerable  quantity  of  serum  abounding  in  hydrogen  and  carbon 
and  of  a  temperature  of  only  thirty  degrees,  yields  its  hydrogen  and  car- 
bon to  the  oxygen  of  the  atmosphere,  to  form  carbonic  acid  and  the  pul- 
monary vapour;  and  as  oxygen  cannot  enter  into  these  new  combinations, 
without  parting  with  a  portion  of  caloric  which  keeps,  it  in  a  state  of 
gas,  the  blood  acquires  this  warmth,  which  is  disengaged  the  more  rea- 
dily, according  to  the  ingenious  experiments  of  Crawford,  as  by  parting 
with  its  hydrogen  and  carbon,  its  capacity  for  caloric  increases  in  the  pro- 
portion of  10  :  1 1.5. 

*  Some  physiologists  think  that  the  quantity  of  air  inspired  is  much  less  considera- 
ble. Professor  Gregory,  of  Edinburgh,  states,  in  his  public  lectures,  that  scarcely 
two  inches  of  air  enter  into  the  lungs,  at  each  inspiration.  It  may  be  proved,  how- 
ever, that  this  calculation  is  inaccurate ;  either  by  drawing-  a  full  inspiration,  as  was 
done  by  Mayosv,  at  the  expense  of  a  cei-tain  quantity  of  air  contained  in  a  bladder,  or 
by  breathing1  into  a  vessel  connected  with  a  pneumatic  apparatus  the  air  taken  in,  by 
drawing-  a  deep  inspiration.  Or  else  one  may  inflate  the  lungs  of  a  dead  body  by 
adapting  to  the  trachea,  a  stop-cock  connected  with  a  curved  tube  to  receive  the  air 
under  a  vessel  of  the  same  apparatus.  Various  means  have  been  employed  to  mea- 
sure the  capacity  of  the  chest.  Boerhaave  placed  a  man  in  a  tub  containing  water 
above  his  shoulders,  he  then  made  him  take  a  deep  inspiration,  and  measured  the 
height  at  which  the  fluid  rose  from  the  dilatation  of  the  chest.  Keill  injected  water 
into  the  chest  of  a  dead  body.  Lastly,  it  has  been  proposed  to  inject  the  bronchial 
tubes  and  the  lobular  tissue  into  which  they  terminate,  with  fusible  metal  consisting  of 
eight  parts  of  pewter,  five  of  lead,  three 'of  bismuth,  to  which  may  be  added  one  of 
mercury. — Author's  Note. 

t  See  APPENDIX,  Note  W,  for  observations  on  the  changes  induced  on  the  air, 
and  on  the  blood,  by  respiration, 


180 

In  parting  with  its  carbon  which,  by  uniting  with  oxygen,  forms  the 
carbonic  arid  that  is  thrown  out  during  expiration,  the  blood  loses  its 
dark  and  nearly  purple  colour,  and  becomes  of  a  florid  red,  and  its  con- 
sistence increases,  from  the  escape  of  its  hydrogen  and  of  its  aqueous 
parts.  Besides,  as  it  absorbs  a  certain  quantity  of  oxygen,  it  becomes 
spumous  and  light  :  its  concrescibility  and  plasticity  increase,  and  on 
coagulating,  there  is  separated  from  it,  a  smaller  quantity  of  serum. 

After  parting  with  its  hydrogen  and  carbon,  ^hd  combining  with  oxy- 
gen and  caloric,  in  its  passage  through  the  lungs,  the  blood,  which  has  be- 
come arterial,  parts  with  these  two  principles,  in  proportion  as  in  reced- 
ing from  the  heart,  it  forms  new  combinations,  and  is  converted  into  oxy- 
des  of  hydrogen  and  carbon,  which  on  receiving  an  additionl  quantity  of 
oxygen,  are  changed  into  water  and  carbonic  acid,  when  on  being  carried 
along  with  the  venous  blood,  into  the  pulmonary  tissue,  they  are  exposed 
to  the  influence  of  the  atmospherical  air. 

The  arterial  blood  becomes  venous,  by  yielding  its  oxygen,  when  any 
cause  whatever  suspends  or  slackens  its  course,  as  is  proved  by  the  fol- 
lowing experiment  of  John  Hunter.  He  tied  the  carotid  artery  of  a  dog, 
with  ligatures  placed  at  the  distance  of  about  four  inches  from  each  other: 
the  blood  contained  in  the  portion  of  artery  included  between  the  two  li- 
gatures, on  laying  open  this  part  of  the  vessel,  at  the  end  of  a  few  hours, 
was  found  coagulated  and  as  dark  as  that  in  the  veins.  The  blood  con- 
tained in  an  anetorismal  sac,  and  which  is  frequently  found  in  a  fluid  state, 
when  the  internal  coats  of  the  artery  are  but  lately  ruptured,  becomes 
venous  after  remaining  in  it  some  time.  The  changes,  however,  which 
the  blood  undergoes  in  its  course  through  the  arterial  system,  are  not 
very  remarkable,  owing  to  the  rapidity  with  which  it  flows  along  those 
vessels;  there  is  less  difference  between  the  blood  contained  in  an  artery 
near  the  heart,  and  that  contained  in  an  artery  at  a  distance  from  that  or- 
gan, than  in  the  blood  taken  from  the  veins  near  their  extremities,  and 
from  the  great  trunks  which  deposit  it  into  the  right  auricle.  The  blood 
in  the  small  veins  resembles  arterial  blood,  and  frequently  in  a  very  co- 
pious bleeding,  the  colour  of  the  blood,  which,  at  first,  is  very  dark, 
gradually  becomes  less  dark,  till  towards  the  end  of  the  bleeding,  it  shows 
nearly  the  same  qualities  as  if  arterial ;  a  phenomenon  which,  as  is  well 
observed  by  the  English  writer  already  quoted,  depends  on  the  more  easy 
and  rapid  flow  of  the  blood'of  the  arteries  into  the  veins,  in  consequence 
of  the  evacuation  of  the  venous  system.  This  observation  is  a  complete 
icfutation  of  the  assertion  of  Bellini,  who  maintains,  that  when  a  vein  is 
wounded,  the  blood  which  comes  from  it,  forms  a  double  current  which 
flows  out  at  the  wound.  The  above  opinion  is  maintained  by  highly  dis- 
tinguished phosiologists,  as  Haller  and  Spallanzani,  who  support  it  by 


*  Sir  Humphrey  Davy  gives  the  following  results  of  experiments  made  on  his  own 
respiration : 

After  one  strong  expiration,  his  lungs  contained  330  cubic  inches ;  after  a  natural 
expiration,  970  cubic  inches;  after  a  natural  inspiration,  11Q6  cubic  inches;  after  a 
strong  inspiration,  3206.  By  a  strong  expira^on,  after  a  deep  inspiration,  1556  cubic 
inches  were  thrown  out  of  the  lungs.  After  a  natural  inspiration,  643  cubic  inches, 
and  after  a  natural  expiration,  353.  Mr.  Thompson  supposes  that  the  quantity  of  air 
usually  contained  in  the  lungs  is  2294  cubic  inches,  and  that  327  cubic  inches  enter  or 
escape  in  inspiration  or  expiration.  If  we  allow  20  inspirations  a  minute,  we  should 
have  entering  and  escaping  from  the  lungs  in  this  time  6500  cubic  inches,  and  in 
twenty-four  hours,  75,556  cubic  inches,  or  48  pounds. — Godman, 


experiments  performed  on  the  vessels  of  cold-blooded  animals,  or  on 
veins  without  valves.  In  bleeding  at  the  bend  of  the  arm,  the  blood  can- 
not come  from  that  part  of  the  vessel  which  is  above  the  wounds:  the 
valves  oppose  insuperable  obstacles  to  its  retrograde  flow;  hence  it  is 
very  easy  to  distinguish  the  red  blood  which  comes  from  the  lower  extre- 
mity of  the  vein,  from  that  which  flows  from  the  upper  end,  and  which 
is  poured  into  the  vessel  by  the  veins  which  open  into  it,  between  the 
puncture  and  the  nearest  valve. 

In  its  course  to  the  parts  among  which  the  arteries  are  distributed, 
the  blood,  vivified  in 'its  passage  through  the  lungs,  and  fitted,  as  Four- 
croy  says,  for  a  new  life,  loses  its  oxygen  and  caloric.  Its  capacity  for 
the  latter,  diminishes,  in  proportion  as  the  oxygen,  by  combining  with 
hydrogen  and  carbon,  restores  it  to  the  venous  state. 

This  theory  of  the  process  by  which  the  blood  parts  with  its  oxygen? 
in  its  progress  along  the  blood-vessels,  is  rendered  still  more  probable, 
by  recent  discoveries  on  the  nature  of  the  diamond.  This  substance  is 
the  only  pure  carbon,  and  that  which  is  calle^  so  by  chemists,  is  an  oxyde 
of  carbon  which  owes  its  dark  colour  to  the  oxygen  with  which  it  is 
combined.  Before  these  experiments,  it  was  not  easy  to  determine  the 
particular  condition  of  the  carbon  which  exists  so  plentifully  in  venous 
blood. 

No  precise  calculation  has  yet  been  made,  of  the  quantity  of  the  oxy- 
gen absorbed  by  the  venous  blood,  nor  of  the  quantity  employed  in  the 
combustion  of  hydrogen  and  carbon  in  the  lungs,  so  as  to  form  water  and 
carbonic  acid*. 

Is  the  carbon,  in  venous  blood,  merely  combined  with  oxygen,  or  is  it 
united  with  hydrogen,  so  as  to  form  carburetted  hydrogen  ?  It  appears  to 
me  more  probable,  that  the  oxygen  which  is  absorbed  by  combining  with 
hydrogen,  in  every  part  of  the  body,  produces  the  water  which  dilutes 
the  venous  blood,  renders  it  more  fluid,  and  richer  in  serum  than  arterial 
blood;  while,  by  its  union  with  carbon,  it  forms  an  oxide  that  gives  to  the 
blood  the  dark  colour,  which  is  one  of  its  most  remarkable  characters. 
On  reaching  the  lungs.,  which  are  real  secretory  organs,  the  water  is  ex- 
haled, dissolved  in  the  air,  and  forms  the  pulmonary  transpiration;  the 
oxide  of  carbon,  completely  decomposed  by  an  additional  quantity  of 
oxygen,  constitutes  carbonic  acid,  which  gives  to  the  air  that  is  expired, 
power  of  forming  a  precipitate  in  lime  water. 

The  absorption  of  oxygen  by  the  venous  blood,  explains  how  the  phe- 
nomena of  respiration  are  continued  into  every  part  of  the  body,  and 
produce  the  warmth  uniformly  diffused  over  all  our  organs.  In  propor- 
tion as  the  blood  parts  with  its  caloric,  for  which  its  affinity  diminishes 
as  it  becomes  venous,  the  parts  which  give  out  their  hydrogen  and  car- 
bon, combine  with  it.  If  the  lungs  were  the  only  organs  in  whieh  caloric 
might  be  disengaged,  the  temperature  of  those  viscera  ought  considera- 
bly to  exceed  that  of  other  parts:  experience,  however,  shows  that  the 
temperature  of  the  lungs  is  not  sensibly  more  elevated. 

This  theory  of  respiration,  for  which  we  are  entirely  indebted  to  mo- 
dern chemistry,  is  contradicted  by  no  one  phenomenon.  The  greater  the 

*  Instead  of  saying  that  the  venous  blood  absorbs  oxygen,  it  will  approach  nearer  the 
state  of  our  knowledge  to  believe  that  the  venous  blood  gives  off  its  carbon,  which 
combines,  in  the  lung-s,  with  the  oxygen  of  the  inspired  air.  For  a  full  view  of  the 
latest  opinions  on  this  subject,  see  APPENDIX,  Note  W. 


182 

extent  and  capacity  of  the  lungs,  the  more  frequent  is  respiration,  and 
the  greater  the  warmth  and  vivacity  of  animals.  Birds,  whose  lungs  ex- 
tend into  the  abdomen  by  various  membranous  sacs,  and  whose  bones  are 
hollow,  and  communicate  with  the  lungs,  consume  a  great  deal  of  oxy- 
gen, either  on  account  of  the  magnitude  of  this  respiratory  apparatus, 
or  from  their  frequent,  and,  at  times,  hurried  respiration.  On  that  ac- 
count, the  habitual  temperature  of  their  body,  exceeds  that  of  man  and 
mammiferous  animals.  In  reptiles,  on  the  contrary,  whose  vesicular 
lungs  admit  but  a  very  small  quantity  of  blood,  and  present  to  the  atmo- 
sphere a  surface  of  very  limited  extent,  and  in  which  respiration  is  per- 
formed with  intervals  of  longer  duration,  the  body  is  at  a  temperature 
which,  naturally,  never  rises  above  seven  or  eight  degrees. 

LXXVII.  Though  the  temperature  or  warmth  of  the  body  is  generally 
proportioned  to  the  extent  of  respiration,  to  the  quantity  of  blood  exposed, 
in  a  given  time,  to  the  action  of  the  atmospherical  air,  it  may  be  higher 
or  lower,  according  to  the  degree  of  the  vital  energy  of  the  lungs. 
These  organs  should  not  \yp  considered  as  mere  chemical  receivers  : 
they  act  on  the  air,  digest  it,  as  the  ancients  said,  anil  combine  it  with  the 
blood,  by  a  power  which  is  peculiar  to  them*.  If  it  were  otherwise, 
there  would  be  nothing  to  prevent  a  dead  body  from  being  restored  to 
life,  by  inflating  with  oxygen  its  pulmonary  tissue.  The  ancients  alluded 
to  this  action  of  the  lungs  on  the  air  we  breathe,  by  calling  that  air  the 
pabulum  vitx.  Its  digestion  was,  they  thought,  effected  in  the  lungs,  in 
the  same  manner  as  the  digestion  in  the  stomach,  of  other  aliments  less 
essential  to  life,  and  whose  privation  may  be  borne  for  a  certain  time, 
while  life  is  endangered,  when  the  aeriform  nutriment  ceases  to  be  fur- 
nished to  the  lungs,  for  the  short  space  of  a  few  minutes. 

In  proof  of  the  vitality  of  the  lungs,  and  of  the  share  which  they  have 
in  producing  the  changes  which  the  blood  undergoes  in  passing  through 
them,  I  may  mention  the  experiment  which  proves  that  an  animal  placed 
under  a  vessel  filled  with  oxygen,  and  breathing  that  gas  in  a  pure  state, 
consumes  no  more  of  it,  than  if  it  was  received  into  the  chest,  mixed  with 
other  gases  unfit  for  respiration.  A  guinea  pigi  placed  under  a  vessel 
full  of  vital  air  and  of  known  capacity,  will  live  four  times  longer  than  if 
the  vessel  contained  atmospherical  air.  No  remarkable  difference  is  at 
first  perceived  in  the  act  of  respiration,  but  if  the  animal  remains  long 
immersed  in  the  oxygen,  his  respiration  becomes  more  frequent  his  cir- 
culation more  rapid,  all  the  vital  functions  are  executed  with  more  ener- 
gy. The  lungs  separate,  by  a.  power  inherent  in  themselves,  the  two  at- 
mospherical gases,  and  this  process  is  effected  by  a  considerable 
power,  for  oxygen,  in  its  combination  with  the  blood,  is,  with  difficulty, 
separated  from  azote.  Inifact,  the  blood,  though  in  thin  layers,  becomes 
dark,  when  exposed  to  the  atmospherical  air. 

It  is  observed,  that  the  purity  of  the  air  contained  in  the  receiver,  is 
the  more  readily  affected,  as  the  animal  placed  under  it  is  younger,  more 
robust,  and  his  lungs  are  more  capacious.  Hence,  birds,  whose  lungs  are 
very  large,  contaminate  a  considerable  quantity  of  air,  and  consume  more 
quickly  its  respirable  part.  A  frog,  on  the  contrary,  will  remain  a  con- 
siderable time,  in  the  same  quantity  of  air,  without  depriving  it  of 
its  oxygen. 


*  See  APPENDIX,  Note  W, 


„  The  vesicular  lungs  of  that  reptile,  as  v/ell  as  of  all  oviparous  quadru- 
peds, are  much  more  irritable  than  those  of  warm-blooded  animals;  they 
appear  to  contract,  at  the  will  of  the  animal.  The  frog  is  without  a  dia- 
phragm, attracts  the  air  into  its  lungs,  by  swallowing  it  by  a  real  process 
of  deglutition,  as  was  proved  by  Professor  Rafn,  of  Copenhagen,  who 
killed  those  animals  by  holding  their  jaws  asunder  for  a  certain  time, 
They  reject  the  air  by  a  contraction  of  the  lungs,  in  the  same  manner  as 
in  man,  the  bladder  empties  itself  of  urine. 

In  birds,  whose  diaphragm  is  equally  membranous,  and  contains  seve- 
ral openings  to  transmit  the  air  into  the  pulmonary  appendices,  the  pari- 
etes  of  the  thorax  are  likewise  more  moveable  than  in  man  and  quadru- 
peds. Their  pectoral  muscles  are  more  powerful,  their  ribs  contain  a 
joint  situated  in  the  middle  of  those  arches,  which  are  completely  ossified 
in  that  class  of  animals  ;  and  those  two  portions  move  on  each  other, 
forming,  at  their  point  of  union,  angles  more  or  less  acute,  according  to 
the  distance  of  the  sternum  from  the  vertebral  column. 

A  numerous  class  of  cold  red-blooded  animals,  viz.  fishes,  have  no 
lungs;  the  gills,  which  supply  their  place,  are  small  penniform  lamina, 
generally  four  in  number,  situated  on  each  side,  at  the  posterior  and  late- 
ral part  of  the  head,  covered  over  by  a  moveable  lid,  to  which  naturalists 
give  the  name  of  operculum.  The  water  which  the  animal  swallows; 
passes,  when  he  chooses,  through  the  parietes  of  the  pharynx,  which 
contain  several  considerable  openings,  is  spread  over  the  gills  and 
the  pulmonary  vessels  which  are  distributed  in  them,  then  escapes  at  the 
auricular  apertures,  when  the  animal  closes  his  mouth,  and  raises  the 
opercula.  It  is  not  known,  whether  the  water  is  decomposed  and  yields 
its  oxygen  to  the  blood  which  circulates  in  the  gills,  or  whether  the 
small  quantity  of  air  that  is  dissolved  in  the  water,  alone  serves  to  vivify 
the  pulmonary  blood.  The  latter  opinion  seems  the  most  probable,  if  it 
be  considered  that  a  fish  may  be  suffocated,  by  closing  accurately  the 
vessel  of  water  in  which  it  is  enclosed.  The  same  result  might,  I  con- 
ceive be  obtained,  by  placing  the  vessel  under  the  receiver  of  an  air- 
pump,  so  as  to  exhaust  it  completely. 

Respiration,  which  is  completely  under  the  influence  of  the  brain,  as 
far  as  relates  to  its  mechanism,  is  less  dependent  upon  it,  in  regard  to  the 
action  of  the  lungs  on  the  blood,  and  the  combination  of  that  fluid  with 
oxygen,  which  is  the  essential  object  of  that  function.  The  nerves, 
however,  have  some  influence  on  that  function,  as  well  as  on  the  various 
secretions,  in  which,  according  to  Bordeu,  they  are  of  the  first  rate  im- 
portance. Dupuytren  ascertained  by  his  experiments,  that  the  divi- 
sion of  the  cervical  portion  of  the  eighth  pair  of  nerves,  did  not  sensi- 
bly affect  respiration;  but  the  animal  died  with  all  the  symptoms  of  as- 
phyxia, when  this  nerve  was  divided  on  both  sides.  Death  took  place, 
in  the  course  of  a  few  minutes,  when  the  experiment  was  performed  on 
horses.  Other  animals  did  not  die  so  soon  after ;  dogs,  for  instance,  have 
been  known  to  live  several  days  after  the  experiment.  By  interrupting 
the  communication  between  the  lungs  and  the  brain,  we  paralyze  the  for- 
mer of  these  organs,  and  it  ceases  to  convert  the  venous  into  arterial 
blood.  This  fluid,  conveyed  by  the  pulmonary  artery,  continues  of  a  dark 
colour,  when  brought  to  the  left  cavities  of  the  heart;  the  arteries  con- 
vey the  blood  without  its  having  received  its  vivifying  principle,  in  pass- 
ing through  the  lungs  which  are  paralyzed,  by  having  their  nerves  tied 
or  divided.  It  is  easy  to  conceive  that  all  organs,  for  want  of  the  stimu- 


184 

lus  which  determines  their  action,  carry  on  their  functions  imperfectly^ 
and  at  last  cease  to  act.  The  animal  heat  is  likewise  lowered  a  few  de- 
grees, ab  was  ascertained  by  the  above  mentioned  physician,  who  thinks 
he  has  established  as  a  fact,  that  the  ligature  of  the  nerves  of  the  lungs 
does  not  destroy  but  weakens  the  Vital  power,  which  enables  them  to  take 
up  the  oxygen,  and  to  give  out  the  carbonic  acid.  The  brain,  therefore, 
possesses  a  double  influence  over  the  function  of  respiration;  on  the  one 
hand,  it  directs  its  mechanism,  by  means  of  the  nerves  which  it  sends  to 
the  diaphragm,  and  to  the  intercostal  muscles,  and  on  the  other  hand,  it 
is  through  the  nerves  which  arise  from  the  brain,  that  the  lungs  have  the 
power  of  converting  dark  blood  into  arterial  blood,  which  is  the  principal 
phenomenon  of  respiration. 

Experiments  performed  on  the  same  subject,  by  Dr.  Le  Gallois,  subse- 
quent to  those  I  just  related,  tend  to  throw  some  degree  of  uncertainty 
on  their  results.  Dr.  Le  Gallois  repeated  these  experiments  publicly,  in 
my  presence,  and  at  the  society  of  the  Medical  School  of  Paris.  After 
dividing  the  two  nerves  of  the  eighth  pair,  in  a  guinea-pig,  and  after  hav- 
ing, by  that  process,  brought  on  a  state  of  usphyxia,  he  restored  life  and 
motion  to  the  animal,  by  opening  the  trachea  at  its  interior  part.  The 
blood  of  the  carotids,  which  from  red  had  become  dark  the  moment  the 
nerves  were  divided,  respiration  is  restored,  and  the  animal  lives  seve- 
ral days  after  the  experiment.  Whence  does  this  difference  arise  ?  does 
the  division  of  the  eigth  pair  bring  on  asphyxia,  by  occasioning  a  spas- 
modic constriction  of  the  glottis,  and  by  impeding,  or  even  completely 
obstructing  the  admission  of  the  atmospherical  air*? 

LXXVIII.  Of  animal  heat.  The  human  body,  which  is  habitually  of 
a  temperature  of  between  thirty-two  and  thirty-four  degrees  of  Reau- 
mur's thermometerf,  preserves  the  same  degree  of  warmth  under  the 
frozen  climate  of  the  polar  region,  as  well  as  under  the  burning  atmos- 
phere of  the  torrid  zone,  during  the  most  severe  winters  and  the  hottest 
summers.  Nay,  further,  the  experiments  of  Blagden  and  Fordyce  in 
England,  and  of  Duhamel  and  Tillet  in  France,  show,  that  the  human 
body  is  capable  of  enduring  a  degree  of  heat  sufficient  to  bake  animal  sub- 
stances. The  fellows  of  the  Academy  of  Sciences,  saw  two  girls  enter 
into  an  oven,  in  which  fruits  and  animal  substances,  were  being  baked  ; 
Reaumur's  thermometer,  which  they  took  in  with  them,  stood  at  150  de- 
grees; they  remained  several  minutes  in  the  oven,  without  suffering  any 
inconvenience. 

All  living  bodies  have  a  temperature  peculiar  to  themselves,  and  inde- 
pendent of  that  of  the  atmosphere.  The  sap  of  plants  does  not  freeze, 
when  the  thermometer  stands  only  at  a  few  degrees  above  zero;  on  placing 
the  bulb  of  a  thermometer  in  a  hole  in  the  trunk  of  a  tree,  during  winter, 
the  fluid  sensibly  rises.  Now,  three  circumstances  remain  to  be  inves- 
tigated :  in  the  first  place,  what  produces  in  living  bodies,  this  inherent 
and  independent  temperature  ?  In  the  second  place,  how  do  these  bodies 
resist  the  admission  of  a  greater  degree  of  heat,  than  that  which  is  natu- 
ral to  them  ?  What  prevents  caloric,  which  has  a  perpetual  tendency  to  a 
state  of  equilibrium,  from  passing  into  a  body  surrounded  by  a  burning 
atmosphere?  Lastly,  how  does  a  body  which  resists  the  influence  of  heat, 


*  See  APPENDIX,  Note  W. 

f  Between  96  and  98  of  Fahrenheit. 


185 

withstand  equally,   the  destructive  influence  of  an  excessive  degree  of 
cold*? 

LXXIX.  Caloric,  in  a  latent  state,  or  in  combination  with  bodies,  is 
disengaged  from  them,  whenever  they  assume  a  different  state  5  when, 
from  a  gaseous  form  they  become  liquid  ;  or,  when  from  being  liquid, 
they  become  solid.  No\v,  living  bodies  are  a  kind  of  laboratories  in 
which  all  these  changes  are  perpetually  going  on  ;  the  blood  which  cir- 
culates in  every  part  of  the  human  frame,  is  constantly  receiving  supplies 
of  fresh  materials;  from  the  thoracic  duct  which  pours  into  it  the  chyle, 
abounding  in  nutritious  particles  ;  from  respiration  which  imparts  it  to  an 
aeriform  principle  obtained  from  the  atmosphere  ;  and  even,  in  some 
cases,  from  cutaneous  absorption,  through  which  different  elements  are 
received  into  it.  All  these  different  substances  carry  along  with  them 
into  the  blood,  a  certain  quantity  of  caloric,  which  is-  combined  with 
them,  and  which  is  disengaged  during  the  changes  which  they  undergo, 
from  the  influence  of  the  action  of  the  organs,  and  gives  out  its  caloric 
to  the  parts  among  which  it  is  disengaged.  Of  all  the  principles  in  the 
blood,  which  have  the  power  of  communicating  heat  to  the  organs,  none 
furnishes  a  greater  quantity  than  oxygen,  which  during  respiration,  com- 
bines with  the  blood  in  the  lungs.  Gaseous  substances,  it  is  well  known, 
contain  most  combined  caloric;  their  state  of  elastic  fluidity,  is  entirely 
owing  to  the  accumulation  of  that  principle,  and  they  part  with  it,  when 
from  any  cause  whatever,  they  become  liquid.  It  is  on  that  account,  that 
the  heat  of  the  bodies  is  greater,  the  more  they  have  the  power  of  im- 
pregnating their  fluids  with  a  considerable  quantity  of  oxygen  from  the 
atmosphere.  For  the  same  reason,  as  was  already  observed,  in  animals 
that  have  cellular  lungs,  and  a  heart  with  two  ventricles,  the  blood  is  of 
the  same  temperature,  as  in  man  ;  and  such  animals  belong  as  well  as 
man,  to  the  great  class  of  warm  red-blooded  animals;  a  class  in  which 
birds  occupy  the  first  place,  from  the  vast  extent  of  their  lungs,  which 
reach  into  the  abdomen  and  communicate  with  the  principal  bones  of  the 
skeleton.  The  capacity  of  the  pulmonary  organ  of  birds,  is  not  the  only 
cause  why  their  temperature  is  eight  or  ten  degrees  higher  than  that  of 
man  :  this  increase*  of  temperature  depends,  likewise,  on  the  greater 
frequency  of  their  respiration,  and  on  the  velocity  of  their  pulse ;  on 
the  quickness  and  multiplicity  of  their  motions,  and  on -the  vital  activity 
which  animates  them.  In  reptiles  which  have  vesicular  lungs,  and  a 
heart  with  a  single  ventricle,  whose  respiration  is  slow,  and  performed 
at  distant  intervals,  the  blood,  though  red,  is  of  very  inferior  tempera- 
ture to  that  of  man.  They  have,  from  that  circumstance,  been  called 
cold  red-blooded  animals  ;  this  numerous  class  includes  fishes,  which  pos- 
sess an  organ  supplying  but  imperfectly  the  office  of  lungs.  In  fishes, 
the  heart  which  has  but  a  single  ventricle,  sends,  it  is  true,  to  the 
gills  (the  organ  supplying  the  place  of  lungs  is  so  called)  the  whole 
of  the  blood  ;  that  fluid,  however,  is  but  imperfectly  vivified  in  the 
gills,  on  account  of  the  small  quantity  of  air  which  can  be  taken 
in  during  the  act  of  respiration.  Lastly,  in  white-blooded  animals  and 
in  plants,  the  combinations  with  the  air  being  more  difficult,  the  vital 
energy  less,  marked,  the  temperature  differs  only  by  a  few  degrees,  from 

*  See  the  remarks,  in  Api>£*jir\',  Note  Y,  on  the  production  of  Animal  Ifeat. 

2  A 


that  of  the  atmosphere,  and  they  do  not  endure  heat  or  cold,  so  well  as 
the  more  perfect  animals. 

The  lungs,  as  was  before  observed,  consuming  only  a  certain  quantity 
of  air,  there  is  no  increase  of  temperature,  however  great  the  quantity 
of  oxygen  contained  in  the  atmosphere  that  is  breathed  5  as  a  man  who 
should  take  a  double  quantity  of  aliment,  could  not  receive  more  nourish- 
ment, than  if  he  contented  himself  with  the  quantity  of  food  proportion- 
ed to  his  wants  ;  for,  as  the  digestive  organs  can  extract  only  a  certain 
quantity  of  chyle,  the  quantity  of  recrementitious  matter  would  only  be 
greater,  if  more  than  the  due  quantity  of  food  were  received  into  the 
stomach.  Hence  the  common  saying,  that  nourishment  comes  from  what 
we  digest,  and  not  from  what  we  eat. 

The  pulmonary  organ  may,  however  act  on  the  air,  with  different  de- 
grees of  power, 'in  robbing  it  of  its  oxygen:  and  when  the  body  becomes 
of  an  icy  coldness,  in  certain  nervous  and  convulsive  affections,  this  cold 
may  depend  as  much  on  the  atony  of  the  lungs,  and  on  the  spasmodic 
condition  of  the  chest,  which,  dilating  with  difficulty,  does  not  admit  the 
air  readily,  as  on  the  spasm  and  general  insensibility  of  the  organs,  which 
allow  the  blood  to  pass  without  affecting  its  component  parts.  It  would 
be  curious  to  ascertain,  whether  the  air  expired  from  the  lungs  of  a  cata- 
leptic, contains  more  oxygen,  is  less  impaired,  and  contains  a  smaller 
quantity  of  carbonic  acid  than  the  breath  of  a  sound  active  adult.  Per- 
haps it  would  be  found,  that  in  catalepsy  and  other  similar  affections,  the 
blood  does  not  part  with  its  hydrogen  and  carbon,  that  it  retains  its  co- 
louring principles,  and  the  different  materials  of  the  urine,  which  is  void- 
ed in  a  colourless  and  limpid  state,  insipid  and  without  smell,  and  in  the 
condition  of  a  mere  serosity. 

The  temperature  of  the  body  is  produced,  not  only  by  the  pulmonary 
and  circulatory  combinations ;  it  is  besides  developed  in  several  organs, 
in  which  fluid  or  gaseous  substances  become  solid  by  parting  with  a  por- 
tion of  their  caloric.  Thus  digestion,  particularly  of  certain  kinds  of 
food,  is  an  abundant  source  of  caloric;  the  skin  which  is  habitually  in 
contact  with  the  atmosphere,  decomposes  it  and  deprives  it  of  its  caloric. 
Lastly,  caloric  is  produced  and  evolved  in  all  parfs,  whose  molecules 
affected  by  a  double  motion,  in  consequence  of  which  they  are  incessantly 
being  formed  and  decomposed,  by  changing  their  condition  and  consist- 
ence, absorb  or  disengage  more  or  less  caloric.  The  great  activity  of  the 
power  of  assimilation  in  children,  is,  no  doubt,  the  cause  of  the  habitually 
high  temperature,  at  that  period  of  life.  The  temperature  of  the  body 
is  not  only  one  or  two  degrees  higher  at  that  period  of  life;  but  young 
people,  after  death,  preserve  for  a  longer  period  the  remains  of  vital 
heat;  or  rather,  as  tonicity  does  not  so  soon  forsake  the  capillary  vessels, 
life  departing  reluctantly,  the  combinations  from  which  caloric  is  evolved, 
continue  some  time,  even  after  it  is  extinct.  For  the  same  reason,  the 
bodies  of  persons  that  have  died  suddenly,  retain  their  warmth  long, 
while  an  icy  coldness  seizes  the  bodies  of  those  who  have  died  of  linger- 
ing disease,  from  the  slow,  gradual,  and  total  abolition  of  the  powers  of 
life. 

Calorification,  or  the  disengagement  of  animal  heat,  like  nutrition,  takes 
place  at  all  times  and  may  be  considered  as  belonging  to  all  organs.  It 
•was  of  the  utmost  consequence,  that  the  internal  temperature  of  the 
human  body  should  be  nearly  the  same  at  all  times.  For,  let  us,  for  one 
moment,  suppose  that  the  temperature  of  the  blood  should  rise  to  fifty 


18? 

degrees  of  Reaumur's  thermometer,  its  albuminous  parts  would  suddenly 
coagulate,  obstruct  all  the  vessels,  interrupt  the  circulation,  and  destroy 
life.  When,  therefore,  from  an  increased  activity  of  the  nutritive  com- 
binations, a  greater  quantity  of  heat  is  disengaged,  the  animal  economy 
parts  with  it,  and  if  is  taken  up,  in  greater  quantity,  by  the  surrounding 
bodies.  This  accounts  for  the  equality  of  the  temperature  of  the  inter- 
nal parts  of  the  body,  in  old  people,  and  in  children,  notwithstanding  the 
difference  of  their  temperature  externally.  The  difference  consists  in 
this,  that  where  most  caloric  is  produced,  most  is  given  out;  and  though 
the  blood  and  urine  in  old  people,  as  well  as  in  the  young,  are  at  thirty- 
two  degrees,  what  a  difference  is  there  not,  between  the  hot  and  pene- 
trating perspiration  which  is  poured  in  abundance  from  the  child,  and 
the  dryness  and  coldness  of  the  skin  in  old  people;  between  the  sweet 
and  warm  breath  of  the  former,  and  the  frozen  breath  of  the  latter! 
Hence  the  opinion  so  generally  received  and  of  such  antiquity,  that  old 
people  are  benefited  by  cohabiting  with  the  young.  Thus  we  are  told, 
that  David  had  a  young  virgin  brought  to  him,  that  he  might  lie  with 
her,  and  get  heat  in  his  limbs  that  were  stiffened  with  years. 

If  it  be  true,  that  in  the  very  act  of  nutrition,  which  converts  our  fluids 
into  solids,  there  is  disengaged  a  considerable  quantity  of  caloric;  the 
motion  of  nutritive  decomposition,  by  which  our  solids  are  converted  into 
liquids,  must  cause  an  equal  quantity  of  heat  to  be  absorbed.  The  ob- 
jection is  a  very  strong  one,  and  not  easily  got  over;  it  may  be  answered, 
by  observing,  that  all  living  bodies,  from  the  instant  of  their  formation, 
contain  a  certain  quantity  of  caloric  which  they  retain,  so  that  this  double 
process  of  acquiring  heat  and  parting  with  it,  the  unavoidable  result  of 
nutritive  composition  and  decomposition,  merely  keeps  up  an  equili- 
brium, and  maintains  the  same  degree  of  temperature. 

The  blood  which  becomes  saturated  with  oxygen,  in  the  capillaries  of 
the  lungs,  parts  with  that  principle,  and  disengages  its  caloric,  through- 
out the  capillary  vessels  of  the  whole  body,  of  which  each  organ  must 
set  free  a  greater  quantity,  in  proportion  to  the  activity  of  the  living  prin- 
ciple, and  to  the  rapidity  of  the  circulation.  The  parts  through  which 
the  greatest  number  of  vessels  circulate,  perhaps  give  out  most  caloric, 
and  communicate  a  portion  of  it  the  organs,  which  receive  but  a  small 
quantity  of  blood,  as  the  bones,  the  cartilages,  Sec.  It  is  easy  to  under- 
stand, why  an  inflamed  part,  through  which  the  blood  circulates  with 
more  rapidity,  and  whose  sensibility  and  contractility  are  much  increased, 
is  manifestly  hotter  to  the  feel  of  the  patient  and  of  the  physician,  though, 
as  was  observed  by  John  Hunter,  a  thermometer  applied  to  the  inflamed 
part,  shows  a  scarcely  perceptible  increase  of  temperature.  He  injected 
into  the  rectum  of  a  dog,  and  into  the  vagina  of  an  ass,  a  strong  solution 
of  oxymuriate  of  mercury.  Acute  inflammation  came  on,  the  swollen 
mucous  membrane  formed,  externally,  a  considerable  projection.  Blood 
flowed  from  the  torn  capillaries,  yet  the  thermometer  rose  very  slightly, 
only  one  degree  of  Fahrenheit's.  But,  however  slight  that  increase  of 
heat  in  the  inflamed  part,  it  is  very  sensibly  felt,  on  account  of  the  ex- 
treme sensibility  of  the  organ,  whose  vital  properties  are  all  increased*. 
The  liveliness  of  impressions  being  proportioned  to  the  degree  of  the 
power  of  sensation,  one  need  not  wonder  that  the  patient  should  experi- 


*  Whose  capability  to  resist  or  proper  tone  is  very  much  diminished — Godmau, 


188 

ence  a  sensation  of  burning  heat,  in  a  part  in  which  the  thermometer 
indicates  no  increase  of  temperature,  in  which  it  cannot  be  perceived 
even  by  the  touch.  I  have  just^elt  a  young  man's  hand,  that  is  swollen 
from  chilblains;  though  the  pain  which  he  feels  in  it,  seems  to  him  to  be 
occasioned  by  an  accumulation  of  caloric;  his  hand  is  colder  than  mine, 
which  is  of  the  same  degree  of  warmth  as  the  rest  of  my  body,  and  in 
which  I  have  no  peculiar  sensation.  It  may,  therefore,  be  laid  down  as 
an  axiom,  that  the  real  or  thermometrical  increase  of  heat  is  inconside- 
rable in  inflammation,  but  that  it  is  intensely  felt,  in  consequence  of  the 
increase  of  sensibility. 

What  is  the  reason,  that  during  the  cold  fit  of  a  febrile  paroxysm,  a 
sensation  of  excessive  cold  is  felt  in  a  part  in  which  no  diminution  of 
heat  can  be  discovered  by  the  touch  ?  Whence  comes  the  burning  heat 
which  attends  inflammatory  fever  (Kotvtroo-ty  What  is  the  cause  of  the 
difference  of  the  sensations  attending  the  heat  of  erysipelas,  bilious  fe- 
vers, and  phlegmon,  &c.  These  various  sensations  are  owing  to  the  dif- 
ferent modifications  of  sensibility  in  these  different  diseases.  Should 
this  explanation  appear  unsatisfactory,  let  it  be  recollected,  that  however 
accurate  the  calculations  may  be,  that  have  been  made  on  the  subject  of 
caloric,  or  of  the  matter  of  heat,  the  existence  of  caloric  itself  is  hypo- 
thetical, and  that  it  is  not  known,  whether  caloric  is  a  body,  or  whether 
heat  is  merely  a  property  of  matter. 

LXXX.  If  we  now  inquire  into  the  causes  which  enable  the  body  to 
resist  the  admission  of  a  degree  of  heat  superior  to  that  which  habitu- 
ally belongs  to  it,  we  shall  be  compelled  to  admit,  in  all  living  bodies,  a 
power  by  means  of  which  they  repel  an  excess  of  heat,  and  retain  the 
same  temperature.  Cutaneous  perspiration,  it  is  true,  acts  very  power- 
fully in  lowering  the  temperature,  and  as  this  evaporation  increases  with 
the  temperature,  it  would  seem  as  if  this  function  sufficed  to  moderate 
the  heat  of  the  body,  and  to  restore  the  equilibrium. 

It  is  a  fact  known  since  the  time  of  Cullen*,  that  the  evaporation  of 
fluids,  or  their  solution  in  the  air,  is  the  most  powerful  means  of  cooling 
bodies,  and  that  the  mercury  in  the  bulb  of  a  thermometer  may  be  frozen 
merely  by  moistening  it  with  ether,  spirits  of  wine,  or  any  other  volatile 
substance,  and  then  exposing  it  to  a  dry  and  warm  air.  This  method  is 
equally  successful  in  its  application  to  the  human  body,  and  the  hands 
may  be  cooled  to  such  a  degree,  as  to  feel  benumbed,  by  being  frequently 
wetted  with  a  spirituous  fluid,  and  by  being  moved  in  a  dry  and  renewed 
air.  But  though  cutaneous  perspiration  operates  in  a  somewhat  similar 
manner,  and  though  it  may  be  ranked  among  the  means  which  nature 
employs  to  preserve  the  animal  temperature  in  a  nearly  uniform  state,  it 
must  however  be  confessed,  that  it  is  not  the  only  way  in  which  this  ob- 
ject is  accomplished,  and  that  it  does  not  satisfactorily  account  for  this 
phenomenon,  for  the  evaporation  of  the  fluids  contained  in  dead  animal 
substances,  doesnot  prevent  their  being  roasted  on  the  application  of  heatf, 


*  This  celebrated  physician  made  this  discovery  about  forty  years  ago,  which  has 
•thrown  much  light  on  several  physico  chemical  phenomena,  and  he  published  it  in  a 
dissertation  entitled,  "  Of  the  cold  produced  by  evaporating  fluids,  and  of  some  other 
mean  sot' producing  cold,"  by  Dr.  W.  Cullen.— 'Author's  Note. 

f  These  fluids  are  not  renewed  as  fast  as  evaporated,  in  the  roasting  meat,  which  al- 
ways takes  place  in  the  healthy  living  body.  When  the  body  is  exposed  to  a  high 
t  emperature,  we  find  profuse  perspiration  without  change  of  temperature  in  the  system. 


189 

and  besides,  fishes  and  frogs  have  been  known  to  live  and  retain  their 
temperature  in  mineral  waters,  nearly  of  a  boiling  heat*. 

I  thought  it  right  to  repeat  these  experiments,  and  with  this  view,  I 
placed  living  frogs  in  a  vessel  containing  water  at  fifty  degrees  of  tempe- 
rature; and  on  taking  them  out,  at  the  end  of  ten  minutes,  I  ascertained 
that  they  were  not  so  hot  as  the  liquid,  nor  as  pieces  of  flesh  which  had 
been  put  into  it  at  the  same  time. 

We  cannot  admit  the  opinion  of  Grimaud,  that  living  bodies  have  the 
power  of  producing  cold  ;  for,  as  cold  is  merely  the  absence  of  heat,  one 
cannot  allow  a  positive  existence  to  a  negative  being. 

Habit  has  a  remarkable  influence  on  the  faculty  which  the  body  pos- 
sesses, of  bearing  a  degree  of  heat,  much  exceeding  that  which  is  natural 
to  it.  Cooks  handle  burning  coals  with  impunity;  workmen  employed 
in  forges,  leave  the  mark  of  their  feet  on  the  burning  and  liquid  metal, 
at  the  moment  when  it  becomes  solid  by  cooling.  Many,  no  doubt,  re- 
collect the  too  famous  instance  of  a  Spaniard,  who  became  so  general  a 
subject  of  conversation  in  Paris:  this  young  man,  in  making  his  way 
through  a  house  on  fire,  perceived  that  the  heat  was  less  inconvenient  to 
him  than  he  had  imagined.  He  applied  himself  to  bear  with  impunity, 
the  action  of  fire,  and  was  enabled  to  apply  to  his  tongue  a  spatula  heated 
red  hot,  and  to  apply  the  soles  of  his  feet  and  the  palms-  of  his  hands  on 
a  red  hot  iron,  or  on  the  surface  of  boiling  oil.  Nothing  can  equal  the 
absurdity  and  the  exaggeration  of  the  stories  that  were  told  of  this  man, 
except  the  ignorance  and  the  want  of  veracity  of  those  who  invented  them. 
The  following  is  a  correct  statement  of  the  feats  of  this  man,  who  was 
represented  as  incombustible  and  insensible.  He  passes  rapidly  along 
the  surface  of  his  tongue,  which  is  covered  with  saliva,  a  red  hot  spatula, 
the  action  of  which  seems  merely  to  dry  it  by  bringing  on  an  evaporation 
of  the  "fluids  with  which  it  is  covered.  After  carrying  the  spatula  from 
the  base  to  the  tip  of  his  tongue,  he  brings  it  back  again  into  his  mouth, 
and  applies  it  to  his  palate,  to  which  it  communicates  a  part  of  its  heat, 
at  the  same  time  that  it  becomes  moistened  with  saliva.  This  man, 
having,  in  a  public  exhibition,  carried  on  too  long,  the  application  of  the 
spatula,  the  caustic  effects  of  its  heat  showed  themselves,  the  epidermis 
was  detached,  and  found  coiled,  like  the  outer  covering  of  an  onion,  in 
the  cloth  which  he  used  to  wipe  his  mouth.  He  does  not  dip  his  hands 
and  feet  in  boiling  oil,  he  merely  applies  to  the  surface  of  the  fluid  his 
palms  and  his  soles;  and  he  repeats  this  frequently  with  only  a  short  in- 
terval between  each  application.  When  the  experiment  is  carried  on,  for 
a  certain  length  of  time,  there  is  emitted  a  smell  of  burnt  horn.  No  one 
has  yet  observed,  that  though  this  man's  hands  are  not  callous,  the  palms 
of  these,  and  the  soles  of  his  feet  are  cushioned  with  fat.  A  thick  layer 
of  fat,  which  is  a  bad  conductor  of  heat,  separates  the  skin  from  the  sub- 
jacent aponeuroses  and  nerves:  this  circumstance,  to  a  certain  degree, 
account^  for  his  imperfect  sensibility. 

His  £ulse  during  those  experiments,  was  about  a  hundred  and  twenty; 
the  perspiration  evidently  increased,  and  sometimes  copious.  Every  part 

\Vhen  fever  is  present,  we  have  suppression  of  perspiration  and  increase  of  tempera- 
ture.    We  therefore  think  it  superfluous  to  look  for  more  causes  than  are  sufficient  to 
produce  the  effect,  to  say  nothing  of  drawing  inferences  from  changes  produced  on 
dead  matter,  explanatory  of  the  actions  which  take  place  in  living  bodies. — Got&nan. 
*  See  Sonnerat's  Voyage  to  the  East  Indies. 


190 

of  his  body  possesses  the  ordinary  degree  of  sensibility,  may  be  destroyed 
by  the  protracted  application  of  caustic  substances,  and  would  be  con- 
sumed by  fire,  if  applied  for  a  sufficient  length  of  time,  and  nitric  acid 
would  infallibly  destroy  his  tongue,  if  he  took  any  into  his  mouth,  as  it 
has  been  said  he  did.  This  man,  therefore,  in  no  one  respect  departs 
from  the  known  laws  of  the  animal  economy,  but,  on  the  contrary,  affords 
an  additional  proof  of  the  influence  of  habit  on  our  organs. 

LXXXI.  Before  bringing  to  a  conclusion  this  article  on  animal  heat, 
it  remains  for  me  to  explain  how  the  body  resists  cold,  and  preserves  its 
temperature,  in  the  midst  of  a  frozen  atmosphere.  This  cannot  be  ac- 
complished without  an  increase  of  activity  in  the  organs,  it  is  only  by 
augmenting  the  sum  of  the  combinations  by  which  caloric  is  disengaged, 
that  we  can  succeed  in  making  up  for  the  loss  of  that  principle,  so  ne- 
cessary to  our  existence.  What  is  the  reason  that  in  cold  weather  di- 
gestion is  more  active,  (Hieme  vero  ventres  aunt  calidiores,  Hipp.)  the  pulse 
stronger  and  more  frequent,  and  the  vital  energy  greater?  It  is  because 
heat  comes  from  the  same  source,  and  is  produced  by  the  same  mechanism 
as  the  nutrition  of  the  organs;  and  that  its  evolution  may  go  on  increasing, 
it  is  necessary  that  the  secretions,  nutrition,  in  a  word  all  the  vital  func- 
tions, should  increase  in  the  same  proportion. 

Observe,  for  a  moment,  a  man  who  is  exposed  to  a  moderate  degree  of 
cold,  he  feels  more  activity,  more  strength,  and  is  more  nimble,  he  walks 
and  exerts  himself,  the  most  violent  exertions  do  not  appear  to  him,  labo- 
rious, he  struggles  against  the  disadvantages  of  the  debilitating  influence; 
and  provided  the  cold  is  not  excessive,  and  the  body  tolerably  vigorous, 
there  is  disengaged,  within  himself,  a  sufficient  quantity  of  caloric  to 
makeup  for  the  loss  of  that  which  is  carried  off  by  the  air  and  the  surround- 
ing bodies.  These  general  effects  of  cold  are  not  disproved  by  what  hap- 
pens, when  only  a  part  of  the  body  is  exposed  to  it.  Supposing  the  tem- 
perature a  few  degrees  below  zero,  there  is  felt,  at  first,  a  sensation  of 
cold  much  more  inconvenient,  caeteris  paribus,  than  if  it  acted  on  a  more 
extensive  surface.  The  spot  on  which  the  cold  air  acts,  becomes  affect- 
ed with  a  painful  sense  of  pricking,  reddens,  then  inflames  ;  and  in  this 
case,  inflammation  is  evidently  the  result  of  a  salutary  effort  ef  nature 
\vhich  determines  into  the  inflamed  part,  an  excess  of  the  vital  princi- 
ple*, so  that  the  quantity  of  heat  that  is  disengaged  may  correspond  to 
that  which  has  been  abstracted.  The  effort  of  this  conservatory  principle,  is 
more  marked,  than  if  the  whole  surface  of  the  body  were^at  once  exposed 
to  cold,  because,  acting  wholly  on  a  limited  point,  of  small  extent;  it 
operates  with  more  intensity. 

Beyond  a  certain  degree,  however,  nature  in  vain  struggles  against 
cold;  if  severe,  and  if  the  creature  exposed  to  it,  have  not  the  power  of 
sufficient  re-action,  the  part  becomes  purple  and  benumed  from  the  loss 
of  its  caloric,  vitality  ceases,  and  it  mortifies ;  and  if  the  whole  body  is 
equally  exposed  to  the  influence  of  cold,  the  person  is  benumed,  feels  a 
stiffening  of  his  limbs,  stammers,  and  overpowered  by  an  irresistiWe  pro- 
pensity, yields  to  a  sleep  which  inevitably  ends  in  death.  By  yielding 
thus  to  the  illusive  sweets  of  a  perfidious  sleep,  many  travellers  have  pe- 


*  This  pathology  is  incorrect.  The  part  reddens  and  inflames,  because  its  life  has 
been  impaired  and  it  is  no  longer  able  to  bear  the  impulse  given  to  the  blood  by  the 
heart.  Hence  it  becomes  engorged  with  blood,  or  in  other  words  diseased. — Godman. 


191 

fished  after  losing  their  way,  in  the  mountains  of  the  old  and  of  the  new 
world.  Thus,  two  thousand  soldiers  of  Charles  the  Twelfth's  army  pe- 
rished, during  a  siege,  in  the  severe  winter  of  1709. 

To  resist  the  effects  of  cold,  a  certain  degree  of  strength  and  vigour  is 
therefore  necessary ,  it  is  consequently  very  injudicious  to  recommend 
the  cold  bath  to  very  young  children,  to  delicate  and  nervous  women,  to 
persons  whose  constitution  is  not  capable  of  a  sufficient  re-action.  The 
evil  attending  the  injudicious  use  of  this  remedy  in  the  cases  that  have 
just  been  enumerated,  justifies  the  apparently  singular  terms  in  which 
Galen  expressed  himself:  "  Let  the  Germans,  (says  this  first  of  physio- 
logists) let  the  Sarmatians,  those  northern  nations  as  barbarous  as  bears 
and  lions,  plunge  their  children  in  frozen  water;  what  I  write  is  not  in- 
tended for  them." 

On  the  other  hand,  if  it  be  recollected,  that  there  is  within  us  a  power 
of  re-action,  which  increases  with  use,  that  motion  strengthens  our  organs, 
it  will  be  readily  understood,  that  cold  acts  as  a  tonic,  whenever  it  is 
not  applied  to  such  a  degree,  as  to  extinguish  the  vital  power. 

The  manner  in  which  enlightened  physicians  have,  at  all  times,  pres- 
cribed the  cold  bath,  shows  that  they  were  acquainted  with  this  tonic  effect 
depending,  not  on  the  application  of  cold,  which  in  itself  is  debilitating, 
but  on  the  re-action  which  it  occasions.  Hence  along  with  the  cold  bath, 
they  are  in  the  habit  of  recommending  exercise,  a  generous  wine,  bark, 
nutritious  food,  and  an  analeptic  regimen,  calculated  to  excite  a  salu- 
tary re-action. 

LXXXII.  Animal  heat  is,  therefore,  produced  by  the  combination  of 
our  fluids  and  solids  in  the  process  of  nutrition;  it  is  a  function  common 
to  all  the  organs,  for,  as  they  all  nourish  themselves,  so  they  all  disen- 
gage, more  or  less,  the  caloric  combined  with  the  substances  which  they 
apply  to  their  nutrition. 

Though  we  are  without  precise  information  respecting  the  manner  in 
which  a  living  body  resists  the  admission  of  a  degree  of  heat  exceeding 
that  which  is  natural  to  it,  one  may  consider  cutaneous  exhalation,  which 
is  increased  by  the  use  of  heating  substances,  as  the  most  powerful  means 
employed  by  nature  to  get  rid  of  the  excess  of  heat,  and  to  restore  the 
equilibrium. 

Lastly,  the  body  resists  cold,  because  the  organs  being  rendered  more 
active  by  cold,  there  is  disengaged  a  quantity  of  caloric  equal  to  that 
"which  is  carried  off  by  the  air,  or  by  the  other  substances  with  which  the 
body  happens  to  be  in  contact*. 

LXXXIII.  The  rapidity  of  the  circulation  of  the  blood  through  the 
lungs,  is  equal  to  the  velocity  with  which  it  flows  in  the  other  organs. 
For,  if  on  the  one  hand,  the  parietes  of  the  right  ventricle  and  of  the 
pulmonary  artery,  are  weaker  and  thinner  than  those  of  the  left  ventri- 
cle and  aorta,  the  lungs,  from  their  soft,  easily  dilated  and  spongy  tex- 
ture, are  the  most  easily  penetrated  by  fluids  of  all  our  organs. 


*  The  animal  economy  resists  a  moderate  degree  of  cold,  and  is  even  strengthened 
by  it,  owing  to  the  re-action  of  the  vital  influence.  If,  however,  the  degree  of  cold  be 
either  absolutely  or  relatively  great,  the  energy  of  the  system  is  entirely  overwhelmed 
by  its  sedative  operation.  The  effects  of  cold  differ  not  only  according- to  its  degree, 
but  also  according*  to  the  duration  of  exposure  to  it — to  the  state  of  the  nervous 
system  previous  to,  or  dining  the  exposure — and  to  the  general  condition  of  the  body 
at  the  time. —  Copland. 


192 

The  right  ventricle  sends  into  the  lungs  a  quantity  of  blood,  equal  to 
that  which  each  contraction  of  the  left  ventricle  propels  into  the  aorta, 
and  it  is  not  necessary  to  adopt  the  opinion  of  M.  Kruger,  that  each  con- 
traction of  the  heart  sends  into  the  lungs,  and  into  the  rest  of  the  body  an 
equal  quantity  of  blood,  for,  in  that  case,  the  circulation  would  have 
been  much  slower,  the  length  of  the  lungs  being  much  shorter  than  the 
whole  body.  Nor  need  we  say,  with  Boerhaave,  that  this  circulation  is 
much  more  rapid,  because  the  same  quantity  of  blood  returns  by  the 
extremities  of  the  pulmonary  artery,  and  of  all  the  other  arteries  of  the 
body. 

The  extensiou  of  the  pulmonary  tissue,  the  straightening  of  its  vessels 
are,  no  doubt,  favourable  to  the  circulation  of  the  blood,  but  if  the  ad- 
mission of  air  did  not  answer  a  different  purpose,  the  circulation  would 
not  be  indispensably  necessary.  The  blood  flows  from  the  right  into  the 
left  cavities  of  the  heart,  notwithstanding  the  collapse  of  the  lungs  and 
the  creases  of  their  vessels.  The  air  which  penetrates,  at  all  times,  into 
the  lungs,  supports  their  tissue  and  the  vessels  which  are  distributed  to 
it,  so  that  even  during  expiration,  the  vessels  are  much  less  creased,  than 
has  been  imagined  by  several  physiologists.  But  the  changes  produced 
by  the  contact  of  the  atmosphere;  renovate  this  fluid,  and  fit  it  to  re-excite 
and  keep  up  the  action  of  all  the  organs,  which  require  to  be  stimulated* 
by  arterial  blood.  If  you  make  a  living  animal  breathe  de-oxygenated 
air,  the  blood  undergoes  no  change  by  its  pulmonary  circulation;  the 
left  cavities  of  the  heart  are  no  longer  duly  irritated  by  this  fluid,  which 
preserves  all  its  ven.ous  qualities;  their  action  becomes  languid,  and 
with  it  that  of  all  the  organs;  and  in  a  little  while,  it  ceases  altogether. 
It  is  revived  by  introducing  pure  air,  through  a  tube  fitted  to  the  trachea; 
ail  the  parts  seem  to  awake  out  of  a  sort  of  lethongic  sleep;  in  which 
they  are  again  immersed,  by  depriving  the  lungs  anew  of  the  vital  air. 

The  chyle,  mixed  in  great  quantity  with  the  venous  blood,  undergoes, 
in  its  passage  through  the  heart  and  the  sanguineous  system,  a  more  vio- 
lent agitation ;  its  molecules  are  struck  together,  break  on  each  other, 
and,  thus  attenuated,  become  more  perfectly  intermingled:  in  its  passage 
through  the  lungs,  a  great  part  of  this  recrementitious  fluid  is  deposited 
by  a  sort  of  internal  perspiration,  in  the  parenchymatous  substance  of 
these  viscera.  Oxy dated  by  the  contact  of  tne  air,  re-absorbed  by  a  mul- 
titude of  inhalent  vessels,  it  is  carried  into  the  bronchial  glands,  which 
are  found  blackened  by  what  it  there  deposits  of  carbonic  and  fuliginous 
matter.  Purified  by  this  elaboration,  it  returns  into  the  thoracic  duct, 
•which  pours  it  into  the  subclavian  vein,  whence  it  soon  returns  to  the 
lungs,  to  be  there  anew  subjected  to  the  action  of  the  atmosphere ;  so 


*  Some,  hypercritics  very  strenuously  object  to  the  use  of  the  term  stimulation  as  ap- 
plied to  the 'action  of  the  blood  on  the  heart,  and  they  urge  that  all  stimulants  disturb 
or  irritate,  and,  therefore,  are  unnatural,  which  the  blood  certainly  is  not.  Neverthe- 
less, the  blood  is  the  natural  stimulus  or  excitant  of  the  heart,  and  does  in  reality  irritate 
or  disturb  that  organ  under  peculiar  circumstances.  It  is  true  that  the  word  stimulus 
has  by  common  custom  a  more  enlarged  meaning  than  its  bare  etymology  would  allow. 
To  those  who  are  such  sticklers  for  etymology  as  fixing  significations,  we  may  address 
the  following  pertinent  observation  of  the  illustrious  HARVKY  .  "  De  verbi  autem  ety- 
mologia,  non  sum  hie  magnopere  sollicitus  ;  neque  enim  pro  jure  pbilosophico  esse  cre- 
dimus,  ex  verborum  significatione  illiquid  de  naturss  opeiibus  statuere,  aut  disceptationes 
\medicas}  vocare  ad  tribunal  grammatical.  Non  est  nempc  tarn  quaerendum  quid  vo- 
cabuls. proprie  significent,  quam  (VCOMOKO  VTJLOO  rsunpENTrn.'1'  Kp.  1.— 


193 

that  there  is  effected,  through  these  organs,  a  real  lymphatic  circulation, 
of  which  the  object  is  to  bring  on  the  chyle  to  a  higher  degree  of  ani- 
malization*. 

LXXXIV.  Of  pulmonary  exhalation.  It  will  be  remembered,  that  one 
of  the  great  differences  between  the  blood  of  the  arteries,  and  that  of  the 
veins,  consists  in  the  great  quantity  of  serum  found  in  this  last.  It  is  in 
the  lungs  that  the  separation  of  this  aqueous  part  takes  place,  and  that 
its  proportion  is  reduced,  whether  it  be,  that  oxygen  gives  albumen  and 
gelatine  a  greater  tendency  to  concrete,  or  that  the  serum,  formed  by  the 
fixation  of  oxygen  throughout  the  whole  extent  of  the  circulatory  system, 
exhales  from  the  arteries,  and  thus  furnishes  the  matter  of  pulmonary 
exhalation.  It  is  scarcely  possible  to  admit  the  combination  of  oxygen 
with  the  hydrogen  of  the  venous  blood,  and  that  water  is  thus  formed 
from  its  elements,  as  happens  when  storms  are  gathering  in  the  high 
regions  of  the  atmosphere.  If  a  similar  process  can  be  carried  on  in  the 
lungs,  without  producing  deflagration  and  the  various  phenomena  attend- 
ing the  production  of  aqueous  meteors,  it  is  probable,  that  it  furnishes 
but  a  small  part  of  the  exhalation  5  and  that  this  humour,  analogous  to 
the  serum  of  the  blood,  exhales,  completely  formed,  from  the  arterial  ca- 
pillaries ramified  in  the  bronchiae  and  the  lobular  tissue  of  the  lungs.  It 
is  believed,  that  the  quantity  of  the  pulmonary  exhalation  is  equal  to  that 
of  the  cutaneous  exhalation  (four  pounds  in  twenty-four  hours.)  These 
two  secretions  are  supplemental  to  one  another:  when  much  water 
passes  off  by  the  pulmonary  exhalation,  the  cutaneous  is  less,  and  vice 
versa. 

The  surface,  from  which  the  pulmonary  exhalation  is  given  out,  is 
equal,  if  not  superior  in  extent,  to  that  of  the  skiji :  exhalation  and  ab- 
sorption are  at  once  carried  on  from  that  surface,  many  nerves  are  dis- 
tributed to  it,  and  are  slmost  exposed  in  the  tissue  of  the  membranes 
which  are  extremely  thin.  Are  the  miasmata  with  which  the  atmosphere 
is  sometimes  loaded,  absorbed  by  the  lymphatics,  which,  it  is  well  known, 
have  the  power  of  taking  up  gaseous  substances;  or  do  they  merely  pro- 
duce on  the  nervous  and  sensible  membranes  of  the  bronchiae,  and  of  the 
lobular  tissue,  the  impression  whence  the  diseases  of  which  they  are  the 
germ  arise? 

A  part  of  the  caloric  which  is  disengaged  in  the  combinations  which 
oxygen  undergoes  in  the  lungs,  is  taken  up  in  dissolving  and  reducing  in- 
to vapour,  the  pulmonary  exhalation  which  is  the  more  abundant,  accord- 
ing as  respiration  is  more  complete.  Pulmonary  exhalation  should  be 
carefully  distinguished  from  the  mucous  matter  secreted  within  the  bron- 
chiae and  trachea,  and  which  is  thrown  up  by  a  forcible  expiration,  and 
forms  the  matter  of  what  we  spit. 

LXXXV.  Of  asjihyxia^.  The  term  asphyxia,  though  merely  indicating 
a  want  of  pulse,  is  applied  to  any  kind  of  apparent  death  occasioned  by 


-  *  The  two  last  sentences  of  this  paragraph  are  rather  hypothetical.  We  are  not  suf- 
ficiently well  acquainted  with  the  use  of  the  bronchial  glands  to  assign  them  any  posi- 
tive office  in  the  purification  of  the  blood,  nor  do  we  see  how  much  could  be  gained  by 
the  kind  of  circulation  through  these  organs,  supposed  by  our  author.  We  have  always 
understood  that  the  change  is  effected  while  the  blood  is  passing  through  the  pulmo- 
nary arteries,  whence  it  is  returned  by  the  pulmonary  veins  to  the  left  auricle,  pre- 
pared for  the  support  and  nourishment  of  the  body — Godman. 
f  See  APPEIS7D1X3  Note  W. 

2  B 


194 

an  external  cause  and  suspending  respiration,  as  submersion,  strangu- 
lation, the  diminution  of  oxygen  in  the  air  inhaled,  Sec.  The  only  dif 
ference  between  real  death  and  asphyxia,  is,  that  in  this  last  state,  the 
principle  of  life  may  yet  be  re-animated,  \vhilst,  in  the  other,  it  is  com- 
pletely extinct. 

Asphyxia  takes  place  .in  drowning,  because  the  lungs,  deprived  of  air, 
no  longer  impart  to  the  blood  which  passes  through  them,  the  qualities 
essential  to  the  support  of  life.  The  water  does  not  find  its  way  into  these 
viscera;  the  spasmodic  closing  of  the  glottis,  prevents  its  getting  into 
the  trachea  and  its  branches.  Yet  there  is  found  a  small  quantity  in  the 
bronchiae,  after  drowning,  always  frothy,  because  air  has  mixed  with  it, 
in  the  struggles  which  precede  asphyxia.  If  the  body  remain  long  under 
water,  the  spasmodic  state  of  the  glottis  ceases,  water  passes  into  the 
trachea,  and  fills  the  lungs*.  The  anatomical  examination  of  a  drowned 
body,  shows  the  lungs  collapsed,  and  in  the  state  of  expiration  5  the  right 
cavities  of  the  heart,  the  venous  trunks  which  terminate  in  them, and  ge- 
nerally, all  the  veins,  are  gorged  with  bloodf,  whilst  the  left  cavities  and 
the  arteries  are  almost  entirely  empty.  Life  ceases  in  this  kind  of  as- 
phyxia, because  the  heart  has  sent  to  the  different  organs,  and  especially 
to  the  lungs,  no  blood  that  is  not  deficient  in  the  qualities  necessary  to 
their  action;  and  perhaps  also,  because  the  venous  blood  that  is  accu- 
mulated in  the  tissues,  affects  them  by  its  oppressive  and  deadly  influence. 
On  that  account,  the  best  way  of  restoring  the  drowned  to  life,  is  to  blow 
pure  air  into  their  lungs.  This  is  done  by  means  of  bellows  adapted  to 
a  canula  introduced  into  the  nostril;  if  a  proper  apparatus  cannot  be 
procured,  one  might  blow  with  the  mouth  into  that  of  the  drowned  per- 
son, or  into  his  nostrils,  by  means  of  a  tube;  but  air  so  expired,  having 
already  undergone  the  process  of  respiration,  contains  a  much  smaller 
quantity  of  oxygen,  and  is  much  less  fitted  to  excite  the  action  of  the 
heart.  There  remain  several  other  less  efficacious  remedies,  such  as 
friction,  bronchotomy  glysters,  fumigations  and  suppositories,  stimu- 
lating errhines,  and  especially  ammonia.  Stimulants  taken  into  the 
mouth  and  stomach,  the  application  of  fire,  bleeding,  the  bath,  electrici- 
ty, and  galvanism. 

The  redness  and  lividity  of  the  face,  in  persons  who  are  hanged,  had 
led  to  the  opinion  that  death,  in  such  cases,  was  from  apoplexy  $  but  it 
appears  that  in  the  asphyxia  from  strangulation,  as  in  that  from  drowning 
death  is  caused  by  the  interception  of  the  air.  To  prove  this,  Gregory 
performed  the  following  experiment :  he  opened  the  trachea  of  a  dog, 


*  The  lungs£  from  their  Articular  functions,  are  the  organs  which  receive  the -first 
impressions  ifcm  a  multitude of  deleterious  agents.  The  nerves  supplying  the  lungs 
being  very  extensively  and  intimately  connected  with  those  going  to  several  organs  of 
sense,  digestion,  and  assimilation,  whicfc  speedily  suffer  by  sympathy  with  the  part 
originally  injured,  are  frequently  the  least  attended  to  when  we  are  forming  an  opnion 
as  to  the  part  first'operated  on  by  the  pgisoju  We  see  this  particularly  exemplified  in 
jtliasma.tic  fevers,  in  measles  and  small-pox,  which  have  ensued  from  mere  exposure  te 
infecteJVr ;  and,  indeed,  in  all  diseases  communicated  through  the  atmosphere. — 
Though  the  inhalation  of  impure  air  is  confessedly  the  only  mode  in  which  such  affec- 
tions are  produced,  the  first  signs  of  disorder  are  so  generally  observed  in  the  vascular 
or  digestive  system,  as  to  induce  an  entire  forgetfulness  of  the  great  respiratory  appa- 
ratus which  was  first  disarranged. — Godman. 

|  Hence  the  dark  and  livid  colour  of  the  skin  and  conjunctiva.  This  last  membrane 
is  frequently  injected  with  dark  blood ;  the  very  delicate  veins  of  the  brain  are  consi- 
derably diluted,  and  this  viscus  is  distended  with  venous  blood — Copland. 


195 

and  passed  a  noose  round  his  neck,  above  the  wound.  The  animal, 
though  hanged,  continued  to  live  and  to  breathe?  the  air  entered  and 
came  out  alternately,  at  the  small  opening.  He  died,  when  the  constric- 
tion was  applied  below  the  wound.  A  respectable  surgeon,  who  served 
in  the  Austrian  army,  assured  me,  that  he  had  saved  the  life  of  a  soldier, 
by  performing  upon  him  the  operation  of  laryngotomy,  a  few  hours  be- 
fore his  execution. 

Persons  who  are  hanged  may  die,  however,  from  dislocation  of  the  cer- 
vical vertebrae,  and  from  the  injury  done,  at  the  same  time,  to  the  spinal 
marrow.  Loui^,  it  is  well  known,  ascertained,  that  of  the  two  executioners 
in  Lyons  and  Paris,  the  one  despatched  the  criminals  he  executed,  by  dis- 
locating the  head  at  its  articulation  with  the  neck,  while  the  ether  execu- 
tioner destroyed  them,  by  inducing  asphyxia. 

Of  the  different  mephilic  gases  unfit  for  respiration,  some  appear  to 
bring  on  asphyxia,  merely  by  depriving  the  lungs  of  the  vital  air  necessa- 
ry to  the  support  of  life,  while  others  evidently  affect  the  organs  and  the 
blood  which  fills  them,  by  their  poisonous  and  deleterious  influence. 

One  may  mention,  among  the  former,  carbonic  acid  ,  in  the  asphyxia 
occasioned  by  this  gas,  and  which  of  all  others  is  the  most  frequent,  the 
blood  preserves  its  fluidity,  the  limbs  their  suppleness,  and  the  body  its 
natural  warmth,  or  even  a  greater  degree  of  warmth,  for  some  hours  after 
death;  for,  this  kind  of  asphyxia  occurring  always  in  a  very  hot  situation, 
the  body  deprived  of  life,  admits  of  an  excess  of  caloric,  such  as  would 
have  been  resisted,  if  the  vital  power  had  not  been  suspended.  However, 
in  this  asphyxia,  as  in  the  preceding,  the  lungs  remain  uninjured  ,•  the 
rig-lit  cavities  of  the  heart  and  the  venous  system,  are  gorged  with  a  dark 
but  fluid  blood.  In  the  asphyxia,  on  the  other  hand,  that  is  occasioned 
by  sulphureted  or  phosphureted  hydrogen,  Sec.  or  by  certain  vapours 
whose  nature  is  well  understood,  and  which  escape  from  privies,  or  from 
vaults  in  which  a  number  of  dead  bodies  undergo  putrefaction  ;  these  are 
frequently  found  in  the  lungs,  dark  and  gangrenous  marks,  and  death 
seems  the  effect  of  a  poison  which  is  the  more  active,  as  its  particles,  ex- 
ceedingly divided  and  in  a  gaseous  state,  are  more  insinuating,  and  affect 
throughout  its  whole  extent,  the  nervous  and  sensible  surface  of  the 
lungs*. 

Inebriation  seldom  goes  the  length  of  bringing  on  asphyxia,  it  most 
commonly  produces  a  stupor  readily  distinguished  from  the  affection 
treated  of  in  this  article,  by  the  perceptible,  though  obscure  pulse,  and 
by  the  motions  of  respiration,  though  these  are  rare  and  indistinct.  On 
this  account,  M.  Pinel,  in  his  Noaografihie  Philasophique,  has  placed  inebri 
ation  and  the  different  kinds  of  asphyxia,  in  two  separate  genera  of  the 
class  neuroses.  It  is  conceivable,  however,  that  the  muscular  irritability 


*  The  celebrated  Mr.  Goodwin,  not  to  mention  others,  concurs  with  our  author,  in 
the  opinion  that  the  carbonic  acid  destroys  life,  and  produces  its  lesser  mischievous  ef- 
fects merely  by  the  preclusion  of  oxygen.  These  writers,  however,  are  undoubtedly 
mistaken.  Nothing  is  more  clear  than  that  this  species  of  gas  has  a  positive  operation 
en  the  animal  economy.  We  will  state  a  few  facts  in  proof  of  it. 

1.  It  has  been  shown,  that  animals  die  much  sooner  when  exposed  to  the  carbonic 
acid,  than  when  placed  in  vacuo,  or  when  a  ligature  is  applied  to  the  trachea. 

2.  It  has  been  shown,  that  frogs  may  be  kept,  without  injury,  for  upwards  of  an  hour 
under  water,  but  perish  almost  instantly  if  put  into  an  atmosphere  of  fixed  air. 

3.  It  has  been  shown,  that  when  the  carbonic  acid  is  combined'  with  water  it  very 
speedily  destroys  fish.—  Chapman, 


196 

may  be  so  far  impaired  by  the  use  of  spiritous  liquors,  that  the  heart  and 
diaphragm  might  lose  the  power  of  contraction,  which  would  bring  on 
complete  asphyxia. 

The  glottis,  through  which  the  atmospherical  air  passes  in  its  way  to 
the  lungs,  is  so  small,  that  it  may  be  readily  obstructed,  when  the  epiglot- 
tis rising  at  the  moment  of  deglutition,  the  substance  that  is  sw.allowed 
stops  at  the  orifice  of  the  larynx ;  a  grape  seed  may  produce  this  effect, 
and  it  was  in  this  manner,  we  are  told,  that  Anacreon,  that  lovely  poet  of 
the  graces  and  of  voluptuousness,  came  by  his  death.  Gilbert,  the  poet, 
died  after  a  long  and  painful  agony,  from  the  introduction  of  a  small  key 
into  his  throat,  during  a  fit  of  insanity.  A  great  eater,  in  the  midst  of  a 
feast,  went  into  an  adjoining  room,  and  did  not  return,  to  the  great  sur- 
prise of  all  the  guests.  He  was  found  stretched  on  the  floor,  without  any 
sign  of  life.  Help,  given  by  ignorant  people,  was  of  no  use.  On  opening 
the  body,  a.  piece  of  mutton  was  found  fixed  in  the  larynx,  and  complete- 
ly stopping  the  passage  of  the  air. 

Sometimes  a  child  is  born,  and  shows  no  sign  of  life.  When  it  is  pro- 
bable from  the  circumstances  of  the  delivery,  that  there  has  been  no  or- 
ganic injury  decidedly  mortal,  it  must  be  considered  as  a  case  of  asphyx- 
ia,* from  weakness  5  and  all  means  employed  that  are  recommended  in 
such  cases,  especially  blowing  in  air  into  the  lungs,  by  means  of  a  tube 
introduced  into  the  mouth  or  nostrils.  It  is  thus,  that  the  Prophet  Elisha 
restored  to  life  the  son  of  the  Shunamite,  as  we  are  informed,  in  the  se- 
cond book  of  Kings,  chapter  the  fourth. f 

LXXXVI.  Of  certain  phenomena  of  respiration,  as  sighing,  sobbing, 
yawning,  sneezing,  coughing,  hiccup,  laughing,  fyc.  When  the  imagination 
is  strongly  impressed  with  any  object,  when  the  vital  functions  are  lan- 
guid, the  vital  principle  seems  to  forsake  all  the  organs,  to  concentrate 
itself  on  those  which  partake  most  in  the  affection  of  the  mind.  When  a 
lover,  in  the  midst  of  an  agreeable  reverie,  sighs  deeply,  and  at  intervals, 
a  physiologist  perceives  in  that  expression  of  desire,  nothing  but  a  long 
and  deep  inspiration,  which,  by  fully  distending  the  lungs,  enables  the 
blood,  collected  in  the  right  cavities  of  the  heart,  to  flow  readily  into  the 
left  cavities  of  that  organ.  The  deep  inspiration,  which,  is  frequently 


*  The  following  case  of'AspHTXiA  in  a  child  of  six  months  old,  and  the  manner  in 
which  it  was  relieved,  may  be  interesting  to  some  of  the  profession.  While  at  the 
house  of  my  friend,  Mr.  James  Peale,  some  time  since,  one  of  the  family  came  out  to 
Ihe  door,  where  1  was  standing,  and  informed  me  with  great  consternation  that  the  child, 
(then  labouring  under  pertussis,)  had  attempted  to  cough,  and  was  suffocating,  in  conse- 
quence of  inability  to  discharge  the  phlegm.  Hastily  entering  the  room,  I  saw  the  babe 
in  the  arms  of  the  nurse,  hanging  forward,  to  all  appearance  dead ;  its  lips  of  a  dark 
purple,  the  eyes  of  the  same  colour,  closed,  and  the  eyeballs  projecting  very  much.  I 
immediately  applied  my  mouth  over  that  of  the  infant,  and  made  a  strong  effort  to  ex- 
lumst  the  air  from  its  lungs,  closing  the  nostrils  with  one  hand.  The  first  and  second  ef- 
forts were  unavailing.  Almost  despairing  of  success,  1  placed  my  mouth  over  the  mouth 
and  nostrils  of  the  child,  and  made  another  violent  inspiration,  when  to  my  great  joy  the 
clot  of  phlegm  was  thrown  out,  and  the  breathing  was  gradually  restored  to  its  ordinary 
state  in  a  very  few  seconds. — God-man  t 

f  The  reader  need  not  be  reminded  that  French  philosophers  account  for  the  miracles 
related  in  Scripture,  as  they  please,  at  least,  there  is  no  reference  to  such  a  mode  of  re- 
storing life  in  the  following  sentence. 

"  And  he  went  up  and  lay  upon  the  child,  and  put  his  mouth  upon  his  mouth,and  his 
eyes  upon  his  eyes,  and  his  hands  upon  his  hands ;  and  he  stretched  himself  upon  the 
child ;  and  the  flesh  of  the  child  waxed  warm." — 2  Kings,  c.  iv.  34.— Godman. 


J97 

accompanied  by  groans,  becomes  necessary,  as  the  motions  of  respiration 
rendered  progressively  slower,  are  no  longer  sufficient  to  dilate  the  pul- 
monary tissue. 

Sobbing  differs  from  sighing,  merely  in  this,  that  though  the  expiration 
is  long,  it  is  interrupted,  that  is,  divided  into  distinct  periods. 

Yawning  is  effected  in  the  same  manner ;  it  is  the  certain  sign  of  ennui, 
a  disagreeable  affection,  which,  to  use  the  expression  of  Brown,  may  be 
considered  as  debilitating  or  asthenic.  The  fatigued  inspiratory  muscles 
have  some  difficulty  in  dilating  the  chest,  the  contracted  lungs  are  not 
easily  penetrated  by  the  blood  which  stagnates  in  the  right  cavities  of  the 
heart,  and  produces  an  uneasy  sensation,  which  is  put  an  end  to  by  along 
and  deep  inspiration  ;  the  admission  of  a  considerable  quantity  of  air  is 
facilitated  by  opening  the  mouth  widely,  by  the  separation  of  both  jaws. 
One  yawns  at  the  approach  of  sleep,  because  the  agents  of  inspiration, 
being  gradually  debilitated,  require  to  be  roused  at  intervals.  One  is, 
likewise,  apt  to  yawn  on  waking,  that  the  muscles  of  the  chest  may  be 
set  for  respiration,  which  is  always  slower  and  deeper,  during  sleep.  It 
is  for  the  same  reason,  that  all  animals  yawn  on  waking,  that  the  muscles 
may  be  prepared  for  the  contractions  which  the  motions  of  respiration 
require.  The  crowing  of  the  cock  and  the  flapping  of  his  wings  seem  to 
answer,  the  same  purpose.  It  is  in  consequence  of  the  same  necessity, 
that  the  numerous  tribes  of  birds  in  our  groves,  on  the  rising  of  the  sun, 
warble,  and  fill  the  air  with  harmonious  sounds.  A  poet  then  fancies  he 
hears  the  joyous  hymn,  by  which  the  feathered  throngs  greet  the  return 
of  the  God  of  light. 

While  gaping  lasts,  the  conception  of  sounds  is  less  distinct,  the  air,  as 
it  enters  the  mouth,  rushes  along  the  eustachian  tubes  into  the  tympanum, 
and  the  membrane  is  acted  upon  in  a  different  direction.  The  recollec- 
tion of  the  relief  attending  the  deep  inspiration  which  constitute  gaping, 
the  recollection  of  the  grateful  sensation  which  follows  the  oppression 
that  was  felt  before,  involuntarily  leads  us  to  repeat  this  act  •whenever 
we  see  any  one  yawning. 

Sneezing  consists  in  a  violent  and  forcible  expiration,  during  which  the 
air,  expelled  with  considerable  rapidity,  strikes  against  the  tortuous  nasal 
passages,  and  occasions  a  remarkable  noise.  The  irritation  of  the  pitui- 
tary membrane  determines,  by  sympathy,  this  truly  convulsive  effort  of 
the  pectoral  muscles,  and  particularly  of  the  diaphragm. 

Coughing  bears  a  considerable  resemblance  to  sneezing,  and  differs 
from  it,  only  in  the  shorter  period  of  duration  and  the  greater  frequency 
of  the  expirations ;  and  as  in  sneezing,  the  air  sweeps  along  the  surface 
of  the  pituitary  membrane,  and  clears  it  of  the  mucus  which  may  be  ly- 
ing upon  it,  so  the  air,  when  we  cough,  carries  along  with  it  the  mucus 
contained  in  the  bronchiae,  in  the  trachea  and  which  we  spit  up.  The 
violent  cough,  at  the  beginning  of  a  pulmonary  catarrh,  the  sneezing 
which  attends  coryza,  show  that  the  functions  of  the  animal  economy 
are  not  directed  by  an  intelligent  principle,  for  such  an  archseus  could  not 
mistake,  in  such  a  manner,  the  means  of  putting  a  stop  to  the  disease, 
and  would  not  call  forth  actions  which  instead  of  removing  the  irritation 
and  inflammation  already  existing,  can  only  aggravate  them. 

Laughing  is  but  a  succession  of  very  short  and  very  frequent  expira- 
tions. In  hiccup,  the  air  is  forcibly  inspired,  enters  the  larynx  with  dif- 
ficulty, on  account  of  the  spasmodic  constriction  of  the  glottis;  it  is  then 
expelled  rapidly,  and  striking  against  the  sides  of  that  aperture,  occasions 
the  particular  noise  attending  it. 


*> 


198 


I  shall  on  another  occasion,  explain  the  mechanism  of  sucking,  oi' 
panting,  and  of  the  efforts  by  which  the  muscles  of  the  thorax  fix  the  pa- 
rietes  of  that  cavity,  so  that  it  may  serve  as -a  fixed  point  of  the  other 
muscles  of  the  trunk  and  the  limbs. 

Respiration  is  besides  employed  in  the  formation  of  the  voice,  but  the 
voice  and  the  different  modifications  of  which  it  is  capable,  will  form  the 
subject  of  a  separate  chapter*. 

LXXXVII.  Of  cutaneous  perspirations.  An  abundant  vapour  is  continu- 
ally exhaling  from  the  whole  surface  of  the  body,  and  is  called  the  insen- 
sible perspiration,  when  in  a  state  of  gas  in  the  air  which  holds  it  in  solu- 
tion, it  then  eludes  our  sight;  it  isValled  sweat,  when  in  greater  quantity 
and  in  a  liquid  form.  Sweat  differs,  therefore,  from  insensible  perspira- 
tion, only  by  the  condition  in  which  it  appears,  and  it  is  sufficient  for  its 
production,  that  the  air  should  be  incapable  of  reducing  it  into  vapour, 
whether  from  an  increased  secretion  by  the  skin,  or  from  the  dampness 
and  consequent  diminished  solvent  powers  of  the  atmosphere.  The  insen- 
sible perspiration  is  constantly  escaping  through  the  innumerable  pores  in 
the  parietes  of  the  minute  arteries  of  the  integuments;  it  oozes  in  the  in- 
terstices of  the  scales  of  the  skin;  the  air  which  immediately  surrounds 
our  body,  becomes  saturated  with  it,  and  carries  it  off,  as  soon  as  it  is  re- 
newed. There  is  the  greatest  resemblance,  between  the  cutaneous  pers- 
piration and  the  pulmonary  exhalation;  both  are  mere  arterial  exhalations, 
and  the  mucous  membrane,  which  lines  the  canals  along  which  the  air  is 
transmitted,  is  a  mere  prolongation  of  the  skin  into  these  organs  and  into 
the  digestive  tube.  The  surface  from  which  the  cutaneous  perspiration 
it  exhaled,  is  not  quite  so  considerable  as  that  from  which  the  pulmonary 
exhalation  arises,  since  it  is  reckoned  at  only  fifteen  square  feet,  in  a  man 
of  middle  size.  These  two  secretions  are  supplementary  to  each  other ; 


*  The  a&thor  has  neglected  to  notice  the  state  of  respiration  during  the  most  active 
voluntary  motions.  Muscular  exertion?  especially  when  considerable,  is  preceded  by 
a  long  and  deep  inspiration,  the  glottis  is  closed*,  the  diaphragm  and  respiratory  mus- 
cles of  the  chest  are  contracted,  and  the  reaction  of  the  abdominal  muscles  cause  the 
contents  of  the  abdomen  to  be  pressed  upon  in  all  directions.  At  the  same  time  that 
the  respiratory  muscles  are  exerted,  those  of  the  face  are  associated,  in  the  increased 
action,  in  consequence  of  the  latter  receiving  some  nerves  from  the  same  class,  (see 
the  notes  in  the  APPENDIX  on  the  different  orders  and  functions  of  the  voluntary 
system  of  nerves)  and  the  jaws  are  forcibly  pressed  together.  By  this  action  of  the 
muscles  engaged  in  respiration,  the  chest  is  rendered  capacious,  and  the  strength  is 
greatly  increased,  because  the  trunk  of  the  body  is  thus  rendered  immoveable  in  re- 
spect to  its  individual  parts,  the  muscles  arise  from  fixed  points,  and  consequently,  wield 
the  members  of  the  body,  with  their  full  energy.  HALLER  appears  to  be  correct  in 
concluding  that,  under  a"  state  of  increased  action  of  the  muscles,  the  flow  of  blood  b 
comes  greater  towards  the  head,  and  thus  the  nervous  energy  is  increased,  and  amply 
generated,  by  means  of  this  augmented  flo'y,  so  as  to  keep  up  the  muscular  action  for 
a  longer  period  than  otherwise  would  be  the  case.  During  violent  exertions,  also,  the 
return  of  blood  from  the  brain  is  in  some  degree  impeded. 

The  physiological  s.tate  of  muscular  actions,  as  they  are  related  to  the  mechanical 
function  of  respiration,  is  very  happily  described  by  Shakspeare,  where  he  makes  the 
fifth  Henry  encourage  his  soldiers  at  the  siege  of  Harfieur : — 
Stiffen  the  sinews,'  summon  up  the  blood, 

Now  set  the  teeth,  and  stretch  the  nostrils  wide ; 

Hold  hard  the  breath,  and  bend  up  every  spirit, 

To  his  full  height. 

In  vomiting  also,  and  in  the  action  of  expelling  the  faeces  and  the  contents  of  the  blad- 
der, the  thoracic  and  abdominal  muscles  of  respiration  are  brought  into  action.— Cop- 
land. 


199 

the  increase  of  the  one  is  generally  attended  with  a  sensible  diminution  of 
the  other1;  lastly,  the  mucous  membrane  of  the  intestinal  canal,  besides 
secreting  mucus  exhales  likewise  a  fluid  which  increases  much  in  quantity, 
when  the  cutaneous  perspiration  is  languid,  as  is  proved  by  the  serous 
diarrahceas  so  frequently  occasioned  by  a  suppressed  perspiration.  It 
must  be  owned,  however,  that  notwithstanding  those  analogies  of  structure 
and  function,  in  the  skin  and  mucous  membranes,  there  exists  perhaps  a 
still  more  intimate  connection  between  its  actions  and  that  of  the  organs 
which  secrete  the  urine;  it  has  always  been  observed,  that  when  this  last 
fluid  is  scanty,  there  is  a  greater  cutaneous  perspiration,  and  vice  versa. 

If  we  examine,  with  a  microscope,  the  naked  body,  exposed  during 
summer  to  the  rays  of  a  burning  sun,  it  appears  surrounded  with  a  cloud 
of  steam,  which  becomes  invisible,  at  a  little  distance  from  the  surface. 
And  if  the  body  is  placed  before  a  white  wall,  it  is  easy  to  distinguish  the 
shadow  of  that  emanation.  We  may,  likewise,  satisfy  ourselves  of  the 
existence  of  the  cutaneous  perspiration,  by  the  following  experiment: 
hold  the  tip  of  the  finger,  at  the  distance  of  the  twelfth  part  of  an  inch 
from  a  looking-glass,  or  any  other  highly  polished  surface,  its  surface  will 
soon  be  dimmed  by  a  vapour  condensed  in  very  small  drops,  which  disap- 
pear on  removing  the  finger.  One  may,  in  this  manner,  ascertain  that  the 
cutaneous  perspiration  varies  in  quantity,  in  different  parts  of  the  surface 
of  the  body,  for,  on  placing  the  back  of  the  hand  before  a  looking-glass, 
the  latter  will  not  be  covered  by  vapour. 

No  function  of  the  animal  economy  has  been  the  subject  of  more  in- 
vestigation, nor  has  any  excited  the  attention  of  more  accurate  and  inde- 
fatigable physicians,  than  the  secretion  now  under  consideration.  From 
the  time  of  Sanctorius,  who,  in  the  beginning  of  the  seventeenth  century, 
published  in  his  immortal  work,  "  Medicina  station,"  the  result  of  experi- 
ments carried  on,  for  thirty  years,  with  a  patience  which  very  few  will 
imitate,  to  that  of  Lavoisier,  who  jointly  with  Seguin,  aided  by  the  resour- 
ces of  the  improved  stateof  chemistry,  instituted  an  examination  of  the  in- 
sensible perspiration,  we  find  engaged  in  this  inquiry,  Dodart,  who  in 
1668  communicated  to  the  Academy  of  Sciences,  which  had  been  founded 
but  a  short  time,  the  result  of  his  observations  at  Paris,  under  a  climate 
different  from  that  of  Venice,  where  Sanctorious  lived  : — Keill,  Robinson, 
and  Rye,  who  repeated  the  same  experiments^!  England  and  Ireland  :— 
Linnings,  who  performed  his  in  South  Carolina;  and  several  physiolo- 
gists of  no  less  merit,  as  Gorter,  Hartmann,  Arbuthnot,  Takenius,  Win- 
slow,  Haller,  &c.  who  all  aimed  at  ascertaining,  with  more  precision 
than  had  been  done  by  Sanctorius,  the  variations  in  the  cutaneous  per- 
spiration, according  to  the  climate,  the  season  of  the  year,  the  age,  the 
sex,  the  state  of  health,  or  disease,  the  hour  of  the  day,  and  the  quantity 
of  other  secretions. 

According  toSanctorius,  of  eight  pounds  of  solid  and  liquid  aliments 
taken  in  twenty-four  hours,  five  were  carried  off  by  the  perspiration,  and 
only  three  in  excrement  and  urine.  Haller  conceives  this  calculation  to 
be  exaggerated :  Dodart,  however,  carried  it  still  further,  and  maintained 
that  the  relation  of  the  perspiration  to  the  solid  excrements,  was  as  seven 
to  one. 

In  France  and  in  temperate  climates,  the  quantity  of  the  cutaneous  per- 
spiration, and  of  the  urine,  is  nearly  the  same;  it  may  be  estimated  at  be- 
tween two  and  four  pounds  in  the  twenty-four  hours.  We  perspire  most 
in  summer,  and  void  most  urine  in  winter.  The  perspiration,  like  every 


200 

ether  secretion,  is  in  smaller  quantity  during  sleep,  than  while  we  are 
awake;  in  old  age  than  during  infancy,  in  weak  persons,  and  in  damp 
weather,  than  under  the  opposite  circumstances. 

The  perspiration  may  be  said  to  be  in  a  compound  ratio  of  the  force 
with  which  the  heart  propels  the  blood  into  the  minute  capillary  arteries, 
of  the  vital  energy  of  the  cutaneous  organ,  and  of  the  solvent  powers  of 
the  atmosphere.  The  strongest  and  most  robust  men  perspire  most ; 
some  parts  of  the  skin  perspire  more  than  others,  as  the  palms  of  the 
hands,  the  soles  of  the  feet,  the  arm-pits,  &c.  When  the  air  is  warm, 
dry,  and  frequently  renewed,  cutaneous  perspiration  is  greater,  and  the 
necessity  of  taking  liquid  aliment  is  more  urgent,  and  more  frequently  ex- 
perienced ;  in  summer,  as  every  body  knows,  a  profuse  perspiration  is 
brought  on  by  passing  from  the  heat  of  the  sun  into  the  shade;  and,  on 
no  occasion  is  a  copious  sweat  more  easily  brought  on,  than  by  taking 
exercise  in  summer,  when  on  the  approach  of  a  storm,  the  atmosphere, 
containing  a  small  quantity  of  vapours,  and  warm  from  the  rays  of  the  sun, 
which  shows  itself,  now  and  then,  surrounded  by  the  clouds,  is  little  capa- 
ble of  dissolving  the  insensible  perspiration. 

The  skin  may  be  covered  with  sweat,  without  any  increase  of  the  cuta- 
neows  perspiration;  this  may  happen  from  dampness  in  the  air,  or  from 
its  being  imperfectly  renewed.  It  must  be  owned,  however,  that  sweat- 
ing is  more  frequently  occasioned  by  an  increase  of  the  insensible  perspi- 
ration, and  that  the  warmth  of  the  bed  which  excites  it,  acts  by  increasing 
the  power  of  the  organs  of  circulation  and  the  energy  of  the  cutaneous 
system.  The  body  is  weakened  by  sweating,  which  is  seldom  the  case 
with  the  insensible  perspiration.  A  profuse  sweat  is  attended  with  a 
very  speedy  exhaustion  ;  thus,  in  hectic  fever,  in  the  suelte  (sudor  angli- 
cus)  and  other  affections,  equally  dangerous,  it  is  the  cause  of  a  wasting 
almost  universally  fatal. 

The  matter  of  the  insensible  perspiration  and  of  the  sweat,  is,  in  great 
measure,  aqueous.  Like  the  urine,  it  holds  in  solution  several  salts,  also 
the  volatilized  recrementitious  matter  of  animal  substances,  sometimes 
even  acids,  as  in  the  case  in  which  Berthollet  detected  the  phosphoric 
acid  in  children  affected  with  worms,  in  pregnant  women,  in  nurses,  from 
whom  there  exhales  an  odour  manifestly  acid.  It  may  contain  ammonia, 
and,  on  certain  occasions,  the  smell  enables  us  to  discover  that  alkali,  in 
the  sweat  or  perspiration. 

The  air  which  constantly  surrounds  our  body,  does  not  merely  dissolve 
the  aqueous  vapour  which  arises  from  it,  but  several  physiologists  very 
reasonably  conjecture,  that  the  oxygen  of  the  atmosphere  may  combine 
with  the  carbon  of  the  blood  brought  to  the  skin  by  the  numerous  vessels 
which  are  sent  to  it,  and  likewise  with  the  gelatine  forming  the  substance 
of  the  rete  mucosum  of  Malpighi. 

The  experiments  of  Jurine,  of  Tin  gray,  and  of  several  other  naturalists, 
show  that  carbonic  acid  is  constantly  formed  on  the  surface  of  the  skin,  so 
that  the  skin  may  be  considered  as  a  supplementary  organ  to  that  of  re- 
spiration 5  and  in  that  point  of  view,  one  may  compare  to  it,  the  mucous 
membranes  which  are  in  contact  with  the  atmospherical  air  in  the  nasal 
fossae,  and  in  the  intestinal  canal  which  they  line. 

The  cutaneous  perspiration  is,  likewise  as  was  before  mentioned,  a 
powerful  means  of  cooling  the  body,  and  of  keeping  it  while  living,  in  an 
uniform  temperature.  The  water  which  is  exhaled  from  the  whole  sur- 
face of  the  body,  carries  offfrom  it,  in  passing  into  a  vapour,  aconsidera- 


201 

ble  quantity  of  caloric;  and  it  is  observed  that  every  thing  which  increases 
the  production  of  caloric,  gives  rise  to  a  proportionate  increase  of  the  cu- 
taneous perspiration  and  of  the  pulmonary  exhalation,  so  that  a  constant 
equilibrium  being  kept  up  between  its  production  and  escape,  the  animal 
warmth  always  remains  nearly  the  same*. 

To  conclude,  the  extremities  of  the  nerves  of  our  organs  of  sensation, 
are  ail  moistened  by  a  fluid  varying  in  quantity,  and  which  maintains 
them  in  a  softened  state,  favourable  to  the  exercise  of  their  functions.  It 
was  likewise  necessary,  that  the  membrane  in  which  the  sense  of  touch 
resides  should  be  habitually  kept  moist  by  a  fluid  that  should  penetrate  it 
throughout :  this  use  of  the  insensible  perspiration  is  not  less  important 
than  the  preceding,  on  which  physiologists  have  bestowed  most  atten- 
tion. 


CHAPTER  V. 


OF  THE  SECRETIONS. 

LXXXVIII.  Of  the  animal  fluids.  The  animal  fluids  were  formerly 
divided  into  recrementitious^  excrementitious,  and  excremento-recrementi- 
tious  ;  this  division,  founded  on  the- uses  to  which  the  fluids  are  subser- 
vient 5  is  preferable  to  any  that  has  since  been  adopted,  and  in  which 
they  are  ranked  according  to  their  nature. 

The  first  class  remain  in  the  body,  and  are  employed  in  its  autrition 
and  growth ;  such  as  the  chyle,  the  blood,  the  serosity  which  lubricates 
the  surface  of  the  pleura,  of  the  peritoneum,  and  of  the  other  membranes 
of  the  same  kind.  The  second  kind  are  ejected  from  our  body,  and  can- 
not remain  long  within  it,  without  danger;  such  as  the  urine,  the  matter 
of  insensible  perspiration  and  of  sweat.  Lastly,  those  of  the  third  class 
partake  of  the  nature  of  the  two  preceding,  and  are,  in  part,  rejected, 
while  another  part  is  retained  and  employed  in  the  support  and  growth 
of  the  organ:  this  is  the  case  with  the  saliva,  the  bile,  the  mucus  of  the 
intestines,  Sec.  If  one  affected  to  be  very  minutely  scrupulous,  one 
might  consider  all  the  animal  fluids  as  recremento-excrernentitious.  The 
chyle  and  the  blood,  which  are  so  very  nutritious,  contain  an  abundance 
of  heterogeneous  and  excrementitious  parts  ;  the  urine,  which  of  all  our 


*  If  transpiration  be  restrained  or  stopped,  and  if  the  causes  productive  of  heat  act 
with  intensity,  it  would  appear  that  the  temperature  of  the  surface  of  the  body  rises 
some  degrees  ;  hence  the  reason  that  the  heat  is  so  distressing  in  those  diseases  which 
are  characterized  by  dimi?iished  transpiration,  and  in  which  the  dryness  of  the  skin  is 
so  remarkable,  as  erysipelas,  erythema,  &c.  M.  M.  Berger  and  Delaroche  have  sup- 
posed that  they  have  seen,  when  the  air  of  a  room  is  saturated  with  humidity  and  ren- 
dered very  warm,  that  the  human  body  exposed  to  this  atmosphere  acquires  a  higher 
temperature  than  is  natural  to  it,  the  cutaneous  and  pulmonary  transpiration  either 
being  altogether  arrested  or  imperfectly  performed.  For  farther  observations  on  this 
subject,  see  APPENDIX,  Note  Z.— Copland. 


202 

fluids  is  that  which  may,  with  most  propriety,  be  termed  such,  contains? 
likewise,  aqueous  parts,  which,  while  it  remains  in  the  bladder,  the 
lymphatics  absorb  and  carry  into  the  mass  of  the  fluids. 

Of  all  the  modern  divisions,  Fourcroy's  is  the  best;  Vicq-d'Azir  ac- 
knowledged its  superiority  over  that  proposed  by  Haller,  in  his  Physiolo- 
gy. Fourcroy  admits  six  classes  of  fluids  :  1st  those  which  hold  salts  in 
solution,  as  the  sweat  and  urine  ;  he  gives  the  name  saline  to  such  fluids  : 
2nd,  inflammable  oily  fluids,  all  possessing  a  certain  degree  of  consistence 
and  concrescjbility,  as  fat,  and  the  cerumen  of  the  ears,  &c.;  3d.  the  sa- 
ponaceous fluids,  as  the  bile  and  milk;  4th,  the  mucous  fluids,  as  those 
which  lubricate  the  internal  coat  of  the  intestinal  canal ;  5th,  the  albu- 
minous fluids,  among  which  one  may  rank  the  serum  of  the  blood  ;  6th, 
thefibrinous  fluids,  containing  fibrina,  as  the  fluid  lust  mentioned*. 

In  proportion  as  we  advance  in  our  knowledge  of  animal  chemistry, 
the  defects  of  these  divisions  become  more,  and  more  evident.  In  short, 
the  animal  fluids  are  so  compound,  that  there  is  not  one  which  does  not, 
at  once,  belong  to  several  of  these  classes,  arid  whose  prevailing  element 
is  not  sometimes  exceeded  in  quantity,  by  materials  which  commonly 
form  but  a  small  part  of  them. 

LXXXIX  The  blood  is  the  reservoir  and  the  common  source  of  the 
fluids;  these  do  not  exist  in  the  blood,  with  the  qualities  which  character- 
ize them,  unless,  after  having  been  previously  formed  by  the  secretory 
organs,  they  have  been  absorbed  by  the  lymphatics,  and  conveyed,  with 
the  chyle  and  lymph,  into  the  circulatory  system.  Let  us  briefly  attend 
to  its  nature,  although  this  belongs  more  especially  to  the  department  of 
chemistry.  The  blood  is  red  in  man,  and  in  all  warm-blooded  animals, 
and  even  in  some  whose  temperature  is  not  very  different  frem  that  of  the 
atmosphere,  as  in  fishes  and  reptiles.  This  colour,  of  a  deeper  or  lighter 
shade,  according  as  the  blood  is  drawn  from  an  artery  or  a  vein,  varies 
in  its  degree  of  intensity,  according  to  the  state  of  health  or  weakness. 
It  is  of  a  deep  red  in  strong  and  active  persons,  pale  and  colourless  in 
dropsical  patients,  and  whenever  the  health  is  weak.  By  its  colour 
one  may  judge  of  all  its  other  qualities.  Its  viscidity  is  greater,  its  sa- 
line taste  more  marked,  its  peculiar  smell  stronger,  when  its  colour  is 
deep.  This  colour  is  produced  by  a  prodigious  number  of  globular  mo- 
lecules, which  move  and  float  in  an  aqueous  and  very  liquid  fluid.  When 
the  blood  is  pale,  the  number  of  these  molecules  diminishes,  they  seem 
to  be  dissolved  in  cachexiae. 

The  microscope,  which  affords  the  only  method  of  perceiving  them, 
does  not  enable  one  to  determine  their  bulk  and  their  figure.  Leeu- 
wenhoek,  who  brought  forward  the  idea  of  their  being  so  minute,  by  his 
calculation  that  they  were  one  millionth  part  of  an  inch  in  size,  thought 
them  spherical.  Hew  son  says  they  are  annular,  and  have  an  opening 
in  their  centre.  Others  compare  them  to  a  flattened  lentil,  with  a  dark 


*  BERZELIUS  distinguishes  the  fluids  formed  from  the  blood  into  secretions  properly 
so  called,  and  excretions,  or  those  which  are  directly  discharged  from  tiie  body  The 
former  class  of  fluids  is  destined  to  perform  a  farther  office  in  the  animal  economy- 
all  of  these  are  alcaline ;  they  are  the  bile,  the  saliva,  and  the  fluid  which  is  secreted 
on  the  mucous  and  serous  surfaces.  In  the  latter  division,  acids  predominate,  the  ex- 
cretory  fluids  embrace  the  urine,  the  cutaneous  and  pulmonary  transpiration,  and  the 
milk.  MAGKXDIE  divides  the  secretions  into  exhalations,  folUcular  secretions,  and  glandu^ 
far  secretions.  See  APPENDIX,  Note  A  A,  for  farther  observations  on  this  subject,— 
Copland. 


203 

spot  in  the  middle.  They  are  solid,  and  formed  by  a  nucleus  or  red 
point,  covered  over  by  a  membranous  vesicle,  which  appears  to  be  rea- 
dily formed  and  destroyed. 

XC.  The  blood,  wheti  no  longer  in  the  course  of  the  circulation,  and 
on  being  received  into  a  vessel,  parts  with  its  caloric,  and  exhales,  at  the 
same  time,  a  powerful  smell,  a  gas  to  which,  according  to  some  physio- 
logists (Moscati,  Rosa,  &c.),  it  owes  its  vital  properties,  and  the  absence 
of  which  is  attended  with  a  loss  of  its  vitality  ;  so  that  its  analysis  cannot 
furnish  facts  applicable  to  the  explanation  of  the  phenomena  of  health 
and  disease.  This  odour,  extremely  strong  in  carnivorous  animals,  is 
very  distinguishable  in  man,  especially  in  arterial  blood.  I  remember 
retaining  it,  a  whole  day  in  my  throat,  after  removing  the  dressings,  and 
suppressing  a  hemorrhage,  occasioned  by  a  relaxation  of  the  ligatures,  a 
-week  after  the  operation  for  popliteal  aneurism.  Unless  by  agitation  it 
is  prevented  from  coagulating,  as  it  cools,  its  consistence  increases,  and, 
on  being  laid  by,  it  separates  into  two  very  different  parts,  the  one  aque- 
ous, more  or  less  red,  heavier  than  common  water,  and  evidently  saltish ; 
this  is  called  the  serum,  consisting  of  water,  in  which  are  dissolved  albu- 
men, gelatine,  soda,  phosphates,  and  muriates  of  soda;  nitrate  of  potash, 
and  muriate  of  lime. 

Serum,  though  bearing  some  analogy  to  the  albumen  of  egg,  differs 
from  it,  in  forming  on  coagulating,  a  less  solid  and  less  homogeneous  mass. 
The  albumen  is  evidently  mixed  with  a  portion  of  transparent  gelatine, 
not  coagulable  by  heat.  Albumen  has  so  great  an  attraction  for  oxygen, 
that  it  is  fair  to  presume,  that  the  serum  absorbs  oxygen  and  combines 
with  it,  through  the  very  thin  parietes  of  the  air  cells  of  the  lungs,  and 
that  it  gives  to  the  arterial  blood  that  spumous  appearance  which  is  one 
of  its  distinguishing  characters.  This  oxidizement,  and  the  fixation  of 
the  caloric  which  accompanies  it,  equally  increase  its  consistence.  It 
does  not,  however,  coagulate ;  because  it  is  kept  in  perpetual  motion  by 
the  circulatory  action,  and  is  diluted  by  a  sufficient  quantity  of  water; 
because  the  animal  temperature,  which  never  exceeds  thirty-two  or  thir- 
ty-four degrees,  cannot  give  a  solid  form  to  albumen,  which  coagulates 
only  at  fifty  degrees  of  Reaumur's  thermometer;  and  lastly,  because  as 
serum  contains  a  certain  quantity  of  uncombined  soda,  which  enables  it 
to  turn  green  vegetable  blues,  this  alkali  concurs  in  keeping  the  albumen 
in  a  dissolved  slate,  which  it  renders  fluid,  when  it  has  been  coagulated 
by  the  acids,  by  heat,  or  by  alcohol. 

Amid  the  serum,  and  on  its  surface,  there  floats  a  red  cake,  spongy, 
and  solid,  (insula  rubra}  which,  by  repeated  washing,  may  be  separated 
into  two  very  distinct  parts.  The  one  is  the  cruror  or  the  colouring  mat- 
ter which  mixes  with  the  water;  it  is  a  more  highly  oxygenated  and  more 
concrescible  albumen  than  that  of  the  serum;  it  holds  in  solution  of 
soda,  as  well  as  phosphate  of  iron,  with  an  excess  of  iron*. 


*  It  is  a  more  oxygenated  and  a  more  coagulable  albumen  than  that  of  the  serum. 
The  colouring  part  of  the  blood,  when  incinerated,  after  giving  off  a  considerable  quan- 
tity of  ammonia  during  the  combustion,  leaves  ashes  which,  according-  to  BEHZELIUS, 
are  only  a  hundreth  part  of  its  weight,  and  which  contains  56  parts  of  the  oxide  of  iron, 
8£  of  the  phosphate  of  lime,  a  little  magnesia,  17£  parts  of  lime,  and  16£  of  carbonic 
acid.  The  oxide  of  iron  is  neither  found  in  the  ashes  of  the  coagulable  part  of  tae  se- 
rum, nor  of  those  of  the  fibrine.  BERZELITJS,  however,  farther  informs  us,  that  the 
serum,  although  able  to  dissolve  a  small  portion  of  the  oxides  of  iron,  but  not  of  its 


£04 

other  is  a  solid  and  fibrous  substance,  which,  after  being  repeat- 
edly washed,  has  the  appearance  of  felt,  the  filaments  of  which  cross 
each  other,  are  extensible  and  very  elastic.  This  third  part  of  the  blood 
is  called  fibrina^  it  is  very  similar  in  its  nature  to  muscular  fibre,  and  like 
it,  gives  out,  on  distillation,  a  considerable  quantity  of  carbonate  of  am- 
monia. Fibrina  does  not  evist  in  the  blood  in  a  solid  form,  but  in  a  state 
of  solution,  and  combined  with  the  other  constituent  parts  of  the  fluid, 
as  is  indicated  by  the  appropriate  expression  of  liquid  flesh  (chair  con- 
lante)  first  used  by  Bordeu,  in  speaking  of  the  blood. 

XCI.  If  the  blood  be  exposed  to  the  action  of  fire,  if  it  be  calcined  and 
reduced  to  powder,  and  if  this  pulverized  substance  be  exposed  to  a 
magnet,  the  presence  of  iron  will  be  manifestly  seen  by  the  magnetic  at- 
traction. Authors  do  not  agree  in  their  accounts  of  the  quantity  of  iron 
contained  in  the  blood.  Menghini  says,  there  is  one  part  in  the  hundred ; 
others,  that  it  is  in  the  proportion  of  1  to  303$  so  that  it  is  probable,  that 
this  constituent  principle  of  the  blood,  like  all  the  materials  of  our  fluids, 
may  vary  in  quantity,  according  to  different  circumstances. 

Blumenbach  justly  observes,  that  iron  is  found  only  in  calcined  blood; 
that  none  is  to  be  found  if  it  be  slowly  dried.  This  peculiarity  is  no 
longer  surprising,  since  Fourcroy  has  shown  that  iron  existed  in  the 
blood,  in  combination  with  the  phosphoric  acid,  and  formed  with  that 
acid  a  phosphate  of  iron,  with  an  excess  of  its  base.  -  This  salt  becomes 
decomposed  by  calcination,  the  iron  is  set  free,  and  is  acted  upon  by  the 
magnet.  Physiologists  attribute  the  colour  of  the  blood  to  the  presence 
of  the  oxide  of  iron  in  that  fluid. 

It  has  been  the  received  opinion,  that  the  red  colour  of  the  blood  is 
owing  to  the  presence  of  phosphate  of  iron,  which,  being  conveyed,  of  a 
white  colour  into  the  blood,  along  with  the  chyle,  meets  with  the  pure 
soda,  by  which  it  is  dissolved,  and  from  which  it  receives  its  colour;  the 
colour  of  the  blood  is,  likewise,  owing  to  the  oxulizement  of  the  metallic 
portion,  which  is  in  very  considerable  quantity  in  that  salt.  This  solu- 
tion of  the  phosphate  of  iron  by  soda,  the  oxidizement  of  the  excess  of 
iron,  and  the  absorption  of  oxygen  by  albumen,  constitute,  in  an  especial 
manner,  hematosis  or  sanguification,  which  is  principally  carried  on  in  the 
lungs*. 

The  respective  proportion  of  the  three  parts  into  which  the  blood  sepa- 
rates spontaneously,  varies  considerably.  The  serum  constitutes  about 
one  half  or  three  fourths  of  the  fluid;  the  colouring  matter  and  fibrina 
are  in  inverse  ratio  of  the  serum,  and  it  is  observed,  that  the  more  bril- 

phosphates,  does  not  acquire  a  red  colour  by  this  weak  solution,  -and  that  he  has 
neither  detected  iron  nor  lime  in  the  entire  blood,  although  both  are  so  abundant  in  its 
ashes.  He  therefore  concludes,  that  the  blood  contains  the  elements  only  of  the  phos- 
phate of  iron,  and  of  lime  and  magnesia,  and  of  the  carbonate  of  lime,  united  very  dif- 
ferently from  their  combination  of  these  salts.  Nor  is  it  unlikely  that  these  salts  are 
formed  during  incineration,  from  the  presence  of  the  elements  of  "their  respective  bases 
in  the  blood,  either  in  an  uncombined,  or  in  a  differently  combined  form,  the  other 
elements  being  partly  furnished  by  this  fluid  also,  and  partly  by  the  atmosphere,  during 
the  incineration. — Copland. 

*  This  opinion  of  FOURCROY  respecting  the  source  whence  the  blood  acquires  its  red 
colour,  has,  since  his  time,  been  adopted  by  some,  and  combated  by  other  physiologists. 
It  is  now  entirely  abandoned,  because  it  i"s  known  that  the  colouring  part  of  this  fluid 
may  be  obtained  separately,  and  entirely  exempt  from  iron.  This  colouring1  portion  of 
the  blood,  according  to  M.  VAUQ.UBLIX,  does  not  change  its  colour  when  treated  with 
gallic  acid— a  farther  proof  that  it  contains  no  iron. —  Copland. 


205 

llant  and  red  the  colour  of  the  blood,  the  greater  the  proportion  of  the 
fibrous  part.  The  pale,  aqueous,  and  colourless  blood  of  a  dropsical 
patient  contains  very  little  fibrina.  In  putrid  or  adynamic  fever,  in  which 
bleeding,  as  is  universally  known,  is  improper,  I  have  sometimes  seen  the 
blood  containing  but  a  small  portion  of  fibrina,  and  very  slow  of  coagu- 
lating: its  texture  seemed  to  suffer  from  the  affection  under  which  the 
muscular  organs  were  evidently  labouring.  In  inflammatory  diseases, 
on  the  contraryyRhe  plastic  power  cf  the  blood  is  augmented;  the  fibrina 
is  in  greater  quantity,  even  the  albumen  coagulates  spontaneously,  and 
forms  a  crust  above  the  serum,  which  is  always  in  smaller  quantity*. 

XCIL  Of  the  changes  on  the  blood.  The  fluids  not  only  undergo  changes 
in  their  composition,  in  their  qualities  and  nature,  when  the  action  of  the 
solids  is  itself  altered  ;  but  even  the  absorbent  system  may  introduce  into 
the  mass  of  our  fluids,  heterogeneous  principles,  evidently  the  cause  of 
several  diseases.  In  this  manner,  all  contagions  spread;  the  virus  of 
small-pox,  of  syphilis,  of  the  plague,  Sec.  Thus,  in  time,  the  habitual 
use  of  the  same  aliment  produces  in  our  fluids  a  crasis  or  peculiar  consti- 
tution, which  has,  on  organized  solids,  an  influence  acting  even  on  the 
mindf. 

A  purely  vegetable  diet  conveys  into  the  blood,  according  to  Pythago- 
ras, bland  and  mild  principles:  this  fluid  excites  the  organs  in  a  mode- 

*  According1  to  Mr.  BRA^DB  and  Sir  E.  Hoiwt,  both  venous  and  arterial  blood  contain 
carbonic  acid  in  the  proportion  of  two  cubic  inches  of  the  gas  for  each  ounce  of  blood. 
This  acid  disengages  itself  immediately,  when  a  portion  of  the  warm  blood  is  placed  in 
an  air-pump.  See  APPENDIX,  Note  B  B,  for  farther  remarks  respecting1  the  blood. — 
Copland. 

j-  These  opinions  of  our  author  are  evidently  borrowed  fronx.the  humoural  pathology. 
Of  this  system,  much  is  still  retained,  and  especially  by  me  French  pathologists.  We 
believe  that  the  changes  wrought  in  the  fluids  are  wholly  produced  through  the  inter- 
vention of  the  solids.  Not  thellightest  proof  exists  of  their  being  vitiated  by  the  intro- 
duction of  '•  heterogeneous  principles,"  much  less,  that  the  mixture  is  the  "cause  of 
several  diseases."  It  is  manifest,  that  every  portion  of  the  absorbent  system  has  the 
power,  in  a  very  great  degree,  of  digesting  and  animalizing  the  substances  which  are 
taken  up.  This  property  of  the  absorbents  is  a  provision  of  nature,  to  prevent  noxious 
substances  from  penetrating  into  the  circulation  unchanged.  In  most  instances,  they 
are  fully  adequate  to  this  end.  Where  they  are  not,  the  substance  passes  to  the  firs't 
lymphatic  gland,  which  takes  on  inflammation  and  intercepts  its  further  progress,  as  in 
the  case  of  bubo.  In  this  respect,  therefore,  the  conglobate  glands  may  be  considered 
as  sentinels  guarding  the  exterior  approaches  of  the  body. 

We  are  not  ignorant  that  some  of  the  properties  of  certain  substances,  when  absorbed, 
display  themselves  in  the  secretions  and  excretions,  as  the  odour  of  garlic,  the  colouring 
matter  of  madder,  &c.  &c.  But  it  does  not  hence  follow,  that  they  entered  the  circu- 
lation unchanged. 

Experiments,  indeed,  prove  quite  the  contrary,  as  neither  one  nor  the  other  can  be 
detected  in  the  serum  of  the  blood.  It  seems  to  us  most  probable,  that  the  process  of 
assimilation,  whether  performed  by  the  chylopoietic  viscera,  or  by  the  absorbent  appa- 
ratus, completely  decomposes  all  substances  subjected  to  its  influence,  and,  however 
various  in  their  principles,  reduces  them  to  one 'homogeneous  fluid,  bland  and  inope- 
rative in  its  nature,  or  in  other  words  renders  it  fit  for  the  purpose  of  nutrition.  But, 
in  the  excretions  or  secretions,  being  removed  beyond  the  sphere  of  the  vital  powers, 
chemical  action  takes  place,  by  which  those  substances  are  in  part  or  entirely  regene- 
rated. 

Whether  the  particular  explanation  offered  by  this  hypothesis  be  received  or  not,  the 
fact  at  least  must  be  acknowledged,  that  no  substance  in  its  active  condition  does  enter 
into  the  circulation,  since  experiments  have  shown,  that  however  mild  the  fluid  may  be, 
either  milk  or  mucilage,  oil  or  pus,  it  cannot  even  in  the  smallest  quantity  be  injected 
directly  into  the  blood  vessels  without  occasioning  the  most  fatal  consequences.  As 
regards  the  operation  of  substances  on  the  Jiving  system,  we  do  not  think  it  at  all  ne« 


206 

frate  degree,  and  this  check  over  the  physical  excitement,  facilitates  the 
observance  of  the  laws  of  temperance,  the  original  source  of  all  virtue. 
These  observations  of  ancient  philosophy,  on  the  influence  of  regimen, 
have,  doubtless,  led  their  authors  to  exaggerated  inferences,  but  they 
should  not  be  considered  as  altogether  unsupported.  The  carnivorous 
species  are  marked  by  their  strength,  their  courage,  and  their  ferocity; 
savages  who  live  by  hunting,  and  who  feed  on  raw,  bloody,  and  palpitating 
flesh,  are  the  most  ferocious  of  men;  and,  in  our  country,  in  the  midst 
of  those  scenes  of  horror  which  we  have  witnessed,  and  from  which  we 
have  suffered,  it  was  observed,  that  butchers  were  foremost  in  the  mas- 
sacres, and  in  all  the  acts  of  atrocity  and  barbarity.  I  know  that  this 
fact,  which  w*s  uniformly  noticed,  has  been  explained  by  saying,  that 
the  habit  of  slaying  animals,  had  familiarized  them  to  shed  human  blood. 
But  though  I  do  not  deny  the  existence  of  this  moral  cause,  which  cer- 
tainly operates,  I  think  I  may  add  to  it,  as  a  physical  cause,  the  daily 
and  plentiful  use  of  animal  food,  the  breathing  an  air  filled  with  emana- 
tions of  the  same  kind,  which  they  inhale,  and  which  contribute  to  their 
corpulence,  which  is  sometimes  excessive. 

As  the  plasticity  and  concrescibility  of  the  blood  are  diminished  in  as- 
thenic  diseases,  or  of  debility,  as  putrid  fevers  and  scurvy,  two  causes 
may  be  assigned  for  the  hemorrhages  which  come  on  in  those  diseases, 
\iz.  the  relaxed  state  of  the  vessels  and  the  dissolution  of  the  blood.  In 
scurvy,  the  tissue  of  the  capillaries  is  relaxed,  its  meshes  enlarged,  red 
blood  passes  into  them,  transudes  through  their  parietes,  and  forms  scor- 
butic spots.  I  have  sometimes  seen  those  ecchymoses  or  sanguineous 
cutaneous  transudations,  extend  under  the  skin  of  the  whole  of  one  lower 
extremity.  Petechiae,  in  putrid  fever,  are  formed  in  the  same  manner, 
and  depend,  likewise,  on  the  relaxation  of  the  minute  vessels,  and  on  the 
greater  fluidity  of  the  blood,  whose  molecules  are  less  coherent,  and 
more  readily  separated  from  each  other. 


eessary  to  resort  to  the  circulation  as  a  medium  through  which  it  is  effected.  By  refer- 
ring it  to  that  law  of  the  animal  economy  termed  sympathy  or  consent  of  parts,  we  have 
a  rationale  far  more  consistent  with  those  views  "derived  from  the  present  improved 
state  of  our  knowledge. 

Conformably  to  this  theory,  when  a  substance  either  medicinal  or  poisonous  is  applied 
to  a  susceptible  portion  of  the  body,  externally  or  internally,  an  action  is  excited  which 
is  extended,  more  or  less  according" to  the  diffusibility  of  the  properties  of  the  substance, 
or  the  degree  of  the  sympathetic  connexion  which  the  part  may  have  with  the  body 
generally.  Thus  a  set  of  Actions  is  raised,  every  one  of  which  is  precisely  similar,  pro- 
vided they  are.  confined  to  the  same  system,  by  "which  is  to  be  understood,  parts  of  an 
identity  of  structure.  If,  however,  the  chain  runs  into  other  systems,  it  loses  its  homo- 
genous character,  the  actions  being  modified  according  to  the  peculiar  organization 
of  the  parts  in  which  they  may  take  place. 

To  illustrate  the  more  distinctly  our  meaning,  we  will  state  a  very  familiar  case.  By 
inserting  a  particle  of  variolous  matter  under  the  skin,  local  irritation  is  created  :  in  a 
few  days  tins  action  becomes  diffused,  and  a  fever  ensues,  which  after  a  short  continu- 
ance throws  out  an  eruption,  each  pustule  of  which  is  alike,  because  the  surface  of  the 
body  is  of  a  uniform  structure,  containing  exactly  the  same  sort  of  virus  as  the  primary 
or  parent  pustule.  It  is  in  this  way,  that  morbid  motion  distributes  itself.  When  dis- 
eases arise  from  a  point,  as  in  fact  all  diseases  do,  but  more  strikingly  those  occasioned 
by  inoculation,  the  matter  introduced  is  not  infinitely  divided  and  spread  over  the 
body,  but  the  action  which  that  matter  had  originally  excited.  These  are  general 
principles,  which  apply  to  the  system  in  every  condition,  and  explain  the  modus  ope- 
randi  of  medicines  as  well  as  of' the  causes  of  disease.  Whatever,  in  short,  operates 
on  the  living  frame,  is  obedient  to  the  same  laws.  The  spot  first  acted  upon,  is  th<» 
focus  from  which  is  irradiated  the  more  diffused  impressions.—  Chcpmnu. 


207 

In  the  summer  of  the  year  1801,  I  amputated  the  arm  of  an  old  man  oi' 
sixty,  on  account  of  a  corroding-  and  varicose  ulcer,  which  for  thirty 
years  had  occupied  a  part  of  the  fore  arm,  and  extended  lo  the  elbow. 
All  who  were  present  at  this  operation,  observed  that  the  blood  which 
flowed  from  the  arteries,  was  not  nearly  so  red  as  that  from,  the  arteries 
of  a  young  man,  whose  thigh  had  just  been  taken  off,  on  account  of  a 
scrophulous  caries  of  the  leg;  that  the  venous  blood  was  entirely  dis- 
solved, purple,  and  similar  to  a  weak  dye  of  logwood.  This  blood  did 
not  coagulate,  like  that  of  the  young  man,  it  became  fluid,  and  was  con- 
verted into  a  serum  containing  a  few  colourless  clots. 

Those  who  have  endeavoured  to  find,  in  the  changes  undergone  by 
the  blood  and  the  other  fluids,  the  cause  of  all  diseases,  have  fallen  into 
us  serious  blunders  as  the  determined  solidists,  who  maintain  that  all 
diseases  arise  from  a  deranged  condition  of  the  solids,  and  that  every 
change  in  the  condition  of  the  fluids  is  a  consequence  of  that  derange- 
ment. The  believers  in  the  Immoral  pathology,  have  certainly  gone  too 
far ;  they  have  admitted  that  the  animal  fluids  might  be  acid^  alkalescent, 
acrimonious,  while  we  have  no  proof  whatever  that  they  ever  do  under- 
go such  changes.  The  solidists  have,  likewise,  gone  much  beyond  the 
truth,  in  saying,  that  every  primitive  change  in  the  condition  of  the  fluids 
is  imaginary,  and  that  the  doctrine  of  humoral  pathology  is  without  foun- 
dation. Stahl  relates*  that  the  blood  of  a  young  woman,  who  was  bled 
during  a  fit  of  epilepsy,  was  absolutely  coagulated,  as  if  that  fluid  had 
partaken  in  the  rigidity  affecting  the  muscular  organs.  Some  authors  say 
they  have  met  with  the  same  appearance;!  have,  however,  never  been 
able  to  discover  any  sensible  difference  between  the  blood  of  an  epilep- 
tic patient  and  of  any  other  person  of  the  same  constitution,  of  the  same 
age,  and  living  on  the  same  regimen  ;  and  it  should  be  considered,  that  to 
make  a  just  comparison  of  our  fluids,  it  is  necessary  that  every  thing 
should  be  alike  in  the  persons  from  whom  they  are  taken,  with  the  ex- 
ception of  the  difference  of  which  we  are  to  judge.  In  fact,  the  blood 
has  not  the  same  appearance,  and  does  not  coagulate,  in  the  same  manner, 
when  taken  from  a  child,  a  woman,  or  an  old  man;  from  a  man  who  lives 
abstemiously,  or  from  one  who  lives  on  a  full  dietf. 

After  enumerating  the  changes  which  the  blood  undergoes,  one  might 
speak  of  those  which  affect  the  fluids  that  are  formed  from  it,  one  might 
attend  to  the  greenish,  leek  colour,  and  sometimes  even  darkish  appear- 
ance of  the  bile,  which  is  not  always  of  the  same  degree  of  bitterness  ; 
the  liquid  state  of  the  urine,  which  is  voided  colourless,  without  smell  or 
flavour,  after  a  fright,  or  during  ihe  convulsive  fits  of  hysterical  women  ; 
the  foetid  smell  and  the  viscidity  of  the  saliva,  when  the  salivary  glands 
are  under  mercurial  influence  ;  the  milky  state  of  the  serum  which  lubri- 
cates the  parietes  of  the  abdomen  and  of  the  viscera  which  it  contains, 
after  inflammation  of  the  peritoneum  $  changes  which  almost  universally 


*   Theoria  medica  vera,  page  678. 

t  As  to  the  humoral  pathology,  in  the  present  state  of  our  knowledge,  we  cannot 
help  regarding  it  as  unnecessary  and  unphilosophica'.  Allowing  all  that  may  be  asked, 
in  consequence  of  the  latest  experiments,  we  remain  persuaded  that  the  changes  pro- 
duced in  the  blood  are  secondary  to  previous  alterations  in  the  blood-making  organs. 
Hence  we  prescribe  for  the  digestive  system,  without  reference  to  the  "  humours,"  sure 
that  "  vitiated  fluids"  will  not  long  trouble  us»  after  we  have  excited  the  nervous  sys- 
tem to  a  proper  degree. — Gedman, 


208 

depend  on  a  derangement  of  action  in  the  secretory  organ,  and  sometimes* 
likewise,  on  the  general  condition  of  the  fluids;  for,  a  gland  cannot  se- 
crete a  fluid  endowed  with  the  qualities  which  peculiarly  belong  to  it, 
unless  the  blood  furnish  it  with  the  materials  of  secretion,  and  unless  it  be 
in  a  state  to  bring  about  a  due  combination  of  their  particles.  When  we 
come  to  the  article  of  accidental  secretions,  we  shall  speak  of  some,  of 
those  disorders  of  the  fluids,  depending  on  a  depraved  condition  of  the 
secretory  organs*. 

XC1II.  On  the  transfusion  of  blood.  In  the  midst  of  the  disputes  to 
which  the  discovery  of  the  circulation  gave  rise,  some  physicians  conceiv- 
ed the  idea  of  renovating  completely  the  whole  mass  of  the  fluids,  in  per- 
sons in  whom  they  might  be  vitiated  ;  by  filling  their  vessels  with  the 
blood  of  an  animal,  or  a  person  in  good  health.  Richard  Lower,  known 
by  his  work  on  the  heart,  first  practised  it  on  dogs,  in  1665.  Two  years 
afterwards,  transfusion  was  performed  at  Paris  on  men  :  it  excited  the 
greatest  expectations  :  it  was  thought,  that  by  this  process,  called  trans- 
fusing surgery  (chirurgie  transfusoire,)  all  remedies  would  be  superseded, 
that  henceforth,  to  cure  the  most  serious  and  inveterate  diseases,  it  would 
be  necessary  merely  to  tranfuse  the  blood  of  a  strong  and  healthy  man 
into  the  veins  of  the  diseased  ;  nay,  they  went  so  far  as  actually  to  imagine 
they  might  realize  the  fabulous  fountain  of  Jouvence  ;  they  expected  no 
less,  than  to  restore  youthful  vigour  to  the  old,  by  infusing  into  them  the 
blood  of  the  young,  and  thus  to  perpetuate  life.  All  these  brilliant  chime- 
ras soon  vanished,  some  underwent  the  experiment,  without  any  remark- 
able effects  from  it,  others  were  affected  with  the  most  violent  delirium  ; 
a  lad  of  fifteen  lost  his  senses,  after  suffering  two  months  from  the  most 
violent  fever.  The  legislative  authority  at  last  interfered,  and  prohibited 
those  dangerous  experiments-}-. 

*  See  APPENDIX,  Note  B  B. 

•t  M.  M.  Prevost  and  Dumas  have  recently  made  some  very  interesting  experiments 
on  the  blood,  by  which  they  have  shown  the  different  sizes  and  figures  of  the  globule^ 
in  various  animals,  as  well  as  the  effects  produced  by  transfusion. 

According  to  their  observations  the  diameters  of  the  red  globules  are, 

In  man  ;  the  dog  ;  rabbit  ;  pig  ;  hedgehog  ;  guinea  pig  ;  muscarden  - 

3750 
of  an  (English)  inch  1 

Iu  the  ass          ...        ..........        4175 

1 

Cat  ;  gray  mouse  ;  white  mouse        .  -        *        -        -        -        -        -        4275 

Sheep  ;  horse  ;  mule  ;  ox          -        -        ........        5000 


Chamois;  stag 


She  Goat          .............    .7200 

In  figure,  the  globules  are  all  spherical  in  the  mammalia.  In  birds  they  are  elliptical, 
and  vary  only  in  the  length  of  their  greater  axes.  In  all  cold-blooded  animals  they  are 
also  elliptical.  They  found  the  colourless  globule  existing  in  the  centre  of  the  particles 

of  blood  has  always  the  diameter  of  7500^  in  all  animals  and  whatever  be  the  form  of  the 
globule  containing  it. 


209 

The  experiments  on  the  subject  of  the  transfusion  of  blood  were  repeat- 
ed, but  without  success,  at  the  Academy  of  Sciences.  Perault  oppos  d 
this  new  method,  and  showed  that  it  was  very  difficult  for  one  animal  to 
exist  on  the  blood  of  another,  that  this  fluid,  though  apparently  the  same 
in  animals  of  the  same  age,  was  as  different  from  it  as  the  features  of  their 
face,  their  temper,  See.  that  an  extraneous  fluid  was  thus  introduced,  which 
conveying  to  the  organs  an  irritation  to  which  they  were  not  accustomed, 
must  disorder  their  action,  in  various  ways  5  that  if,  as  an  objection  to 
what  he  had  said,  they  should  bring  forward  what  takes  place  in  graft- 
ing, in  which  the  sap  of  one  tree  nourishes  another  of  a  different  kind,  he 
would  answer,  that  vegetation  does  not  depend  on  so  complicated,  nor  on 
so  delicate  a  mechanism,  as  the  nutrition  of  animals  ;  that  a  hut  may  be 
formed  of  all  kinds  of  stones  taken  at  random  ;  but  that  to  build  a  palace, 
stones  must  be  designedly  shaped  for  the  purpose,  so  that  a  stone  destined 
for  an  arch-,  will  not  do  for  a  wall,  nor  even  for  another  arch*. 

It  would  be  easy,  by  means  of  a  curved  tube,  to  transfuse  the  arterial 
blood  of  an  animal,  from  a  wound  in  its  carotid  artery,  into  the  saphena 
vein  of  a  man,  into  the  internal  jugular,  .or  into  some  of  the  cutaneous 
veins  of  the  fore  arm  ;  but  it  is  to  be  presumed  from  experiments  on 
living  animals,  that  it  would  be  very  difficult  to  transfuse  blood  into  the. 
•arteries,  as  these  vessels,  filled  with  blood,  during  life,  do  not  yield  to  a 
greater  distention.  The  capillaries,  in  which  the  arteries  terminate,  be- 
come corrugated,  and  refuse  to  transmit  a  fluid  which  does  riot  act  upon 
them,  according  to  their  wonted  sensibility.  Such  was  the  result  of  the 
experiments  of  Professor  Buniva:  he  observed,  in  a  living  calf,  that  the 
vessels  did  not  transmit  freely  the  fluid  which  was  forced  into  them,  till 
the  instant  when  the  animal  was  killed,  by  dividing  the  upper  part  of  the 
spinal  marrow.  Attempts  have  been  made  to  turn  to  useful  purposes 
these  experiments  on  transfusing,  by  limiting  the  process  to  the  injecting 
of  medicinal  substances  into  the  veins.  It  is  singular,  that  the  moment  a 
fluid  is  injected  into  the  veins  of  an  animal,  it  endeavours  to  perform  mo- 
tions of  deglutition,  as  if  the  substance  had  been  taken  in  at  the  mouth. 
All  these  attempts  have  been  too  few  in  number,  and  are  not  sufficiently- 
authenticated  to  justify  their  application  to  the  human  subject.  But 
there  is  every  reason  to  believe,  that,  even  with  the  utmost  care,  the  life 
of  those  who  should  submit  to  them,  would  be  endangered  :  so  that  it  is 
at  once  humane  and  prudent  to  abstain  from  themf. 

Animals  bled  till  they  fainted,  died  if  left  alone,  or  when  water  or  serum  of  blood  (at 
100  Fahr.)  was  injected  into  their  veins  If  on  the  contrary  blood  from  an  animal  of  the 
same  species  was  injected,  every  portion  of  blood  thrown  in  re-animated  the  exhausted 
animal.  When  it  had  received  as  much  as  it  had  lost,  it  breathed  freely,  took  food,  and 
regained  its  health.  When  the  injected  blood  was  from  an  animal  of  different  species, 
but  having1  globules  of  the  same  form,  the  relief  was  merely  partial,  and  the  animal 
could  seldom  be  kept  alive  for  more  than  six  days,  diminishing  in  temperature  ^yith 
remarkable  rapidity.  Birds  die  in  most  violent  nervous  affections,  as  if  acted  on  by  viru- 
lent poison,  when  blood  having  spherical  globules  is  injected.  This  consequence  is 
seen  even  where  the  quantity  of  blood  lost  is  small.  In  very  many  cases,  ca»  and  rab- 
bits were  restored  for  some  days  by  injecting  the  blood  of  cows  or  sheep/  even  when 
the  injection  was  not  made  till  twelve  or  twenty -four  hours  from  the  extraction  of  the 
blood  from  the  latter.  The  blood  was  kept  in  a  fluid  state  in  a  cool  place,  either 
by  taking  away  a  certain  quantity  of  fibrine  or  adding  1000th  part  of  caustic  soda. 
When  sheep's  blood  was  injected  into  the  veins  of  ducks,  they  died  after  rapid  and 

strong  convulsions See  Bibliotheque  Universelle  ;  Journal  de  Physique,  Sept.  1821. 

Phil.  Med.  Jour.  p.  193.  vol.  v. — Godman. 

*  Academic  Royale  des  Sciences,  1667,  page  37. 

t  See  APPENDIX,  Note  B  B. 


2iO 

XCIV.  Of  the  secretions.'  It  has  been  said,  in  too  general  a  way,  that 
the  organs  receive  from  the  blood  conveyed  to  them  by  the  arteries,  the 
materials  of'the  fluids  which  they  separate  from  it.  We  have  seen,  that 
the  liver  is  a  remarkable  exception  to  this  general  rule;  the  same  obser- 
vation seems,  likewise,  applicable  to  the  mammae  ;  they  appear  to  receive 
the  elements  of  their  milky  secretion,  from  the  lymphatics,  which  are  so 
very  numerous  in  their  structure  *. 

One  is,  therefore,  justified  in  saying, .that  the  elements  of  our  fluids 
may  be  furnished  by  vessels  of  every  kind,  to  the  organs  in  which  such 
fluids  may  be  elaborated.  The  term  secretion,  whatever  its  etymology 
may  be,  denotes  that  function  by  which  an  organ  separates  from  the  blood, 
the  materials  of  a  substance  which  does  not  exist  in  that  fluid,  with  its 
characteristic  qualities.  By  the  term  secretion,  one  should  not,  there- 
fore, understand  the  mere  separation  of  a  fluid  existing,  before  the  action 
of  the  organ  by  which  it  is  preparedf. 

XCV.  The  difference  between  the  secreted  fluids,  are  evidently  con- 
nected with  those  of  the  organs  employed  in  their  formation.  Thus,  the 
arterial  exhalation  which  takes,  place,  throughout  the  whole  extent  of  the 
internal  surfaces,  maintains  their  contiguity,  throws  out  an  albuminous 
serosity,  which  is  merely  the  serum  of  the  blood,  slightly  changed,  by 
the  feeble  action  of  a  very  simple  organization.  The  analysis  of  the- 
fluid  of  dropsy,  which  is  merely  the  serosity  constantly  transuding  from 
the  surface  of  the  serous  membranes,  as  the  pleura  and  peritoneum, 
shows,  that  it  bears  the  strongest  resemblance  to  the  serum  of  the  blood, 
and  that  it  differs  from  it  only  in  the  varying  proportions  of  albumen  and 
of  the  different  salts  which  it  holds  in  solution. 

This  first  kind  of  secretion,  this  perspiratory  transudation,  would  seem 
to  be  a  mere  filtration,  through  the  pores  of  the  arteries,  of  a  fluid  already 
formed  in  the  blood.  There  is,  however,  besides,  an  inherent  action  in 
the  membranes  whose  surface  it  continually  lubricates.  If  it  were  not  for 
this  action,  the  serum  would  remain  united  to  the  other  constituent  parts 
of  the  fluid,  which  is  in  too  much  motion,  and  at  too  high  a  temperature, 
to  allow  of  a  spontaneous  separation.  The  term  exhalation,  which  is 
applied  to  this  secretion,  gives  an  incorrect  idea  of  it,  for,  exhalation, 
which  is  a  purely  physical  phenomenon,  and  requiring  the  presence  of 
air  to  dissolve  the  fluid  that  is  exhaling,  cannot  take  place  from  surfaces 
that  are  in  absolute  contact,  and  between  which  there  is  no  interval.  The 
character  of  this  mode  of  secretion,  is  the  absence  of  any  intermediate 
substance,  between  the  vasa  afferentia  and  the  excretory  ducts;  the  mi- 
nute arteries  and  veins  which  enter  into  the  structure  of  the  membranes 
being,  at  once,  vasa  afferentia  and  excretory  ducts.  The  fluid  secreted 
by  the  serous  membranes,  though  bearing  a  considerable  analogy  to  the 
serum  of  the  blood,  differs  from  it,  however,  by  being  animalizecl  in  a 
greater  degree.  The  most  important  function  of  these  organs  is,  there- 
fore, tt\at  they  concur  in  the  common  process  of  assimilation ;  the  office 
which  has  long  been  assigned  to  them  of  fascilitating  the  motion  of  the 
organs  which  they  envelope,  by  lubricating  their  surface,  will  appear  to 


*  This  opinion  respecting1  the  source  of  the  secretion  of  milk,  is  now  relinquished  by 
M.  Tlichciand. —  Copland. 

f  Either  the  material  <^ the  fluid  or  the  elements  necessary  to  its  constitution  MUST 
exist,  before  it  can  be  separtued.—- See  Phil.  Med.  Jour.  No.  5.—Godman. 


211 

be  of  very  secondary  importance,  if  it  be  considered,  that  respiration 
is  not  impeded  by  adhesions  between  the  lungs  and  the  pleura,  and  that, 
besides,  the  brain,  which,  when  the  cranium  is"  whole,  is  completely  mo- 
tionless, is  entirely  surrounded  by  a  serous  membrane. 

XCVI.  Next  in  order  to  the  serous  transudation,  which  requires  a  very 
simple  organization,  comes  the  secretion  which  takes  place  in  the  cryptse, 
in  the  glandular  follicles,  and  in  the  mucous  lacunae*  Each  of  these 
small  glands,  contained  within  the  membranes  lining  the  digestive  canal, 
air  tubes,  and  the  urinary  passages,  and  the  collection  of  which  forms  the 
amygdalae,  the  arytenoicl  glands,  Sec.  may  be  compared  to  a  small  bottle 
with  a  round  bottom,  and  a  very  short  neck;  the  membranous  parietes 
of  these  vesicular  cryptae  receive  a  considerable  number  of  vessels  and 
nerves.  The  peculiar  action  of  the  parietes  of  these  different  parts,  de- 
termines the  secretion  of  the  mucus  furnished  by  those  glands.  These 
mucous  fluids,  less  liquid  and  more  viscid  than  the  serosity  which  is  the 
product  of  the  first  mode  of  secretion,  contain  more  albumen  and  a  great- 
er number  of  salts,  differ  still  more  from  the  serum  of  the  blood,  are 
more  animalized,  and  are  of  a*  more  excrem'entitious  nature. 

The  bottom  of  these  ulricular  glandulse,  is  turned  towards  the  parts  to 
which  the  mucous  membranes  adhere ;  their  mouth,  or  neck,  opens  on 
the  surface  at  which  those  membranes  are  in  contact.  These  kinds  of 
excretory  ducts,  wider,  or  narrower,  and  always  very  short,  sometimes 
unite,  run  into  each  other,  and  open  within  the  cavities.  These  common 
orifices,  at  which  several  mucous  glands  empty  themselves,  are  easily- 
seen  on  the  amygdalae,  towards  the  mucous  lacunae  of  the  rectum  and  of 
the  urethra,  at  the  base  of  the  tongue,  8cc.  The  albuminous  fluid,  which 
is  poured  within  those  glandular  cryptae,  remains  some  time  within  the 
cavity,  becomes  thicker  from  the  absorption  of  its  more  fluid  parts ;  for, 
there  are,  likewise,  lymphatics  within  the  texture  of  th^r  parietes.  When 
the  surfaces,  on  which  they  are  situated,  require  to  be  moistened,  this 
small  pouch  contracts,  and  throws  up  the  fluid  with  which  it  is  filled. 
The  secretion  and  excretion  are  promoted  by  the  irritation  which  the 
presence  of  the  air,  of  the  aliment,  or  of  the  urine  occasions,  by.  the 
compression  exerted  by  those  substances,  and  lastly,  by  the  peristaltic 
contractions  of  the  muscular  planes  to  which  the  mucous  membranes  ad- 
here, throughout  the  whole  extent  of  the  digestive  tube. 

XCVII.  Those  fluids  which  differ  much  from  the  blood,  require  for 
their  secretion,  organs  of  a  more  complicated  nature;  such  organs  are 
called  conglomerate  glands,  to  distinguish  them  from  the  lymphatic  glands, 
which  have  been  termed  conglobate.  Those  glands  constitute  the  viscera, 
and  are  formed  by  a  number  of  nerves  and  vessels  of  all  kinds,  arranged 
in  fasciculi,  and  united  by  cellular  membrane.  A  membrane  peculiar  to 
the  organs,  or  supplied  by  those  which  line  the  cavities  in  which  they 
are  contained,  covers  their  outer  part,  and  insulates  them  from  the  neigh- 
bouring organs. 

The  intimate  arrangement  of  the  different  parts  which  form  the  secre- 
tory glands,  the  disposition  of  the  arteries,  of  the  veins  and  nerves,  and 
the  manner  in  which  the  lymphatic  and  excretory  ducts  arise  from  them, 
has  given  rise  to  endless  discussions,  and  formed  the  basis  of  former 
physiological  theories.  What  follows  may  be  considered  as  a  correct 
abstract  of  what  is  known  on  the  subject. 

The  respective  arrangement  of  the  simple  elementary  tissues  which 
enter  into  the  structure  of  the  glands,  and. which  form  their  proper  sub- 


Stance,  or  parenchyma*,  is  different  in  each  of  them  ;  this  explains  their 
differences,  in  the  double  relation  of  their  properties  and  their  uses.—- 
The  arteries  are  not  as  Ruysch  thought,  immediately  continuous  with 
the  excretory  ducts,  nor  are  there  intermediate  glands  between  those  ves- 
sels, as  Malpighi  conceived.  It  seems  more  probable  that  each  gland 
has  its  own  peculiar  cellular  or  parenchymatous  tissue,  in  the  areolse  of 
which,  the*arteries  pour  the  materials  of  the  fluid  which  the  gland  pre- 
pares, in  virtue  of  a  power  which  is  inherent  to  it,  and  which  is  its  distin- 
guishing character.  The  lymphatics  and  the  excretory  ducts  arise  from 
the  parietes  of  those  cells;  and  these  two  kinds  of  vessels  absorb;  the 
one  set,  the  secreted  fluid  which  they  carry  to  the  reservoirs  in  which 
it  accumulates,  while  the  other  set  take  up  that  part  of  the  fluid,  on  which 
the  organ  has  not  completed  its  action  $  in  other  words,  the  residue  of 
secretion. 

XCVIII.  Of  accidental  secretions.  If  one  wished  to  extend  the  idea 
attached  to  the  term  secretion,  one  might  say,  that  every  thing,  in  the 
living  economy  is  performed  by  means  of  the  secretions.  What  is  di- 
gestion, but  the  separation  o'r  secretion  of  the  chylous  or  nutritive  parts  of 
aliments,  from  their  faecal  or  excrementitious  portion?  Do  not  the  absor- 
bents concur  in  this  secretion  ;  may  they  not  be  considered  as  the  excre- 
tory ducts  of  the  digestive  organs  which  acts  on  the  aliment,  in  the  same 
manner  as  a  secretory  gland  acts  on  the  blood  that  contains  the  materials 
of  the  fluid  to  be  elaborated  ?  Respiration,  as  we  have  already  seen,  is  but 
a  double  secretion  which  the  lungs  perform,  on  the  one  hand,  of  the  oxy- 
gen contained  in  the  atmospherical  air,  and  on  the  other  hand,  of  the  hy- 
drogen and  carbon,  of  the  water,  and  of  the  other  heterogeneous  principles 
contained  in  venous  blood;  and,  as  will  be  shown  in  the  ensuing  chapter, 
nutrition  is  but  a  peculiar  mode  of  secretion  which  is  different  in  every  or- 
gan. It  is,  therefore,  only  a  series  of  very  delicate  and  very  complicated 
separations  and  analysis,  that  the  organs  are  enabled  to  make  extraneous 
substances  undergo  such  a  change  of  composition,  as  to  render  them  fit 
for  their  grow  Hi  and  reparation. 

There  is  every  reason  to  believe,  that  the  phenomena  of  sensation  and 
of  motion,  by  means  of  which  man  keeps  up,  with  surrounding  objects, 
the  relations  necessary  to  his  existence,  are  the  result  of  the  secretions 
of  which  the  blood  furnishes  the  materials  prepared  by  the  brain,  by 
the  nerves,  by  the  muscles,  Sec.  A  plant  separates  from  the  earth,  in 
which  its  roots  are  buried,  the  juices  which  it  requires;  these  juices 
constitute  the  sap,  which,  after  being  filtered  through  a  multitude  of  ca- 
nals, supplies  the  different  secretions,  whose  products  are  leaves,  blos- 
soms, and  fruits,  with  gums, essential  oils,  and  acids.  All  organized  bo- 
dies, are,  therefore,  so  many  laboratories,  in  which  numerous  instruments 
spontaneously  perform  various  compositions,  decompositions,  syntheses^ 


*  Do  the  different  appearances  of  the  substance  of  glandular  bodies  depend  on  the 
different  manner  in  which  the  similar  parts  cross  each  other,  and  on  the  different  pro- 
portions in  every  gland ;  or  do  these  differences  of  colour,  of  density,  by  means  of  which 
we  so  readily  distinguish  the  substance  of  the  liver  from  that  of  the  salivary  glands* 
depend  on  the  existence  of  a  peculiar  tissue  in  each  organ ,?  This  question  cannot  be 
answered,  in  the  present  state  of  anatomy.  The  opinion,  however,  which  suppose^ 
the  different  nature  of  the  glands  to  depend  on  the  the  different  proportions  of  those> 
constitutent  parts,  in  each  of  them  appears  the  most  probable. — Author's  Note 


analyses,  which  may  be  considered  as  so  many  secretions  from  the  com- 
mon fluid. 

If  we  confine  ourselves  in  our  view  of  the  subject,  and  limit  our  atten- 
tion to  man,  the  principal  and  almost  the  sole  object  of  our  study,  we 
shall  see  that  the  different  secretions  that  may  take  place  in  him,  are 
extremely  numerous  and  varied,  and  that  a  change  in  the  condition  of 
one  of  his  organs,  is  sufficient  to  enable  it  to  secrete  a  new  fluid.  Hence 
inflammation  in  any  gland,  is  sufficient  to  alter  the  secretion  of  the  organ 
that  is  affected.  A  portion  of  adipose  tissue,  on  being  affected  with  in- 
flammation, shall  secrete,  instead  of  fat,  a  whitish  fluid  known  by  the 
name  of  pus.  The  pituitary  membrane,  when  inflamed,  furnishes  a  mu- 
cas  more  fluid  and  more  abundant,  and  which,  by  degrees,  returns  to 
its  natural  state,  in  proportion  as  the  coryza  goes  off;  the  serous  mem- 
branes, as  the  pleura  and  the  peritoneum,  will  allow  a  greater  quantity 
of  serum  of  a  more  albuminous  quality,  sometimes  even  coagulable 
lymph,  to  exude  5  at  other  times,  inflammation  causes  an  adhesion  of 
their  contiguous  surfaces,  and  as  the  inflammatory  state  varies  in  intensity, 
the  accidential  secretion  will  likewise  vary  as  to  its  qualities  ;  thus,  the 
phlegmonous  inflammation  which  should  furnish,  on  terminating  in  sup- 
puration, a  whitish  fluid,  thick,  consistent,  and  almost  without  smell,  will 
give  out,  if  the  process  is  not  sufficiently  active,  a  serous  pu ^colourless, 
and  without  consistence,  &c.  For  the  same  reason,  the  blood-vessels 
of  the  uterus  pour  out  in  some  women,  a  dark  coloured  blood  while  in 
others,  they  give  out  a  mere  serosity,  very  slightly,  if  at  all  tinged  with 
blood*. 

The  menstrual  discharge,  in  women,  is  the  product  of  a  real  secretion  of 
the  arterial  capilliaries  of  the  uterus,  in  the  same  manner  as  those  vessels 
in  the  pituitary  membrane,  the  membrane  which  lines  the  bronchiae,  the  sto- 
mach, the  intestines,  the  bladder,  Sec.  pour  out  blood  abundantly,  or  allow 
its  transudation,  when  irritation  is  determined  to  those  parts;  in  hemor- 
rhage from  the  nose,  in  bleeding  from  the  lungs,  or  from  the  stomach, 
when  the  vessels  are  not  ruptured  by  external  violence.  Apoplexy  itself, 
whether  sanguineous  or  serous,  may  in  several  instances,  be  ranked  among 
those  secretory  evacuations,  the  quality  of  which  varies,  according  to  the 
energy  of  the  capillaries  which  produce  it.  On  opening  dead  bodies,  one 
frequently  meets  with  a  collection  of  blood  in  the  ventricles  of  the  brain, 
in  persons  who  have  died  from  apoplexy,  yet  the  most  careful  examination 
does  not  enable  one  to  detect  the  slightest  laceration  or  rupture  in  the 
veins,  or  in  the  arteries  within  the  skullf. 


*  To  these  examples  of  morbid  secretions,  others  majs  be  added,  even  more  remark- 
able, as  the  vims  in  rabies  canina,  in  syphilis,  the  small  pox,  &c.  By  some  animals  the 
power  is  possessed  of  secreting  naturally  the  most  virulent  poisons.  Of  this  descrip- 
tion are  many  of  the  reptiles,  but  especially  the  viper,  the  rattle-snake,  &c.  There  are 
others  again,  which  are  distinguished  by  secretions  peculiar  to  themselves.  For  in- 
stance, the  ant  pours  out  a  fluid  of  a  specific  nature,  the  cuttle  fish  a  dark  liquor,  and 
the  skunk  a  fluid  so  offensive  as  to  become  a  means  of  protection,  repelling  by  its  stench 
many  an  assailant. —  Chapman. 

f  That  the  menstrual  discharge  results  from  a  secretory  action  of  the  uterus,  is  a  doc- 
trine which  we  early  adopted,  and  have  taught  in  our  lectures  for  the  last  ten  years. 
Every  other  hypothesis  on  the  subject  is  totally  irreconcileable  with  facts,  and  repug- 
nant to  the  laws  of  the  animal  economy.  The  crude  speculations  of  former  times,  re- 
specting this  operation,  may,  indeed,  be  considered  as  discarded.  Does  any  one,  for  in- 
tance,  whose  knowledge  has  kept  pace  with  the  improvements  of  physiology,  now  en- 


The  nerves,  of  which  there  is  always  a  certain  number  in  the  structure 
of  the  secretory  organs,  and  which  are  principally  branches  of  the  great 
sympathetic*  nerves,  terminating- in  various  ways,  in  their  substance,  give 


tertain  the  notion  of  lunar  influence,  of  fermentat  on,  of  venereal  appetite,  of  general 
plethora  or  local  congestion,  &c.  &c.  ?  The  leading  arguments,  in  defence  of  this  doc- 
trine, nui.)  be  thus  enumerated. 

1.  *lha\  the  uterus,  in  its  villous  and  vascular  structure,  resembles  a  gland,  and  also 
in  iis  diseases,  being  equally  liable  to  scirrhus,  cancer,  &c.  &c. 

2.  That,  like  otiier  secretory  organs,  blood  is  very  copiously  diffused  through  it. 

3.  That,  by  the  arrangement  of  its  vessels,  it  is  evidently  designed  that  the  circula- 
tion should  oe  retarded  for  the  purpose  of  secretion.     The  arteries  are  not  only  exceed- 
ingly convoluted,  but  tney  are  larger,  and  with  thinner  coats  than  their  corresponding 
veins. 

4.  That,  in  common  with  other  secretions,  menstruation  is  often,  at  first,  imperfectly 
performed,  and  is  subject  afterwards  to  vitiation  and  derangement.     In  the  beginning 
the  discharge  is  commonly  thin,  colourless,  and  deficient,  and  recurs  at  protracted  and 
irregular  intervals.      In  some  of  the  particulars,  it  is  analogous  to  these  seminal  secre- 
tion. 

5.  That,  in  many  of  the  inferior  animal^  during  the  season  of  venereal  incalescence, 
there  is  an  uterine  effusion  which  is  undoubtedly  a  secretion.     This  answers,  seemingly, 
the  same  end  as  menstruation,  namely,  giving  to  the  uterus  an  aptitude  for  conception. — 
Though  this  fluid  generally  differs  from  the  menses  in  complexion,  yet  in  some  instan- 
ces, they  are  precisely  similar.     Whenever  the  veneral  desire  suffers  a  violent  exacer- 
bation from  restraint  or  other  causes,  the  discharges  in  these  animals  become  red.  This 
has  been  more  especially  remarked  in  bitches  kept  from  the  male. 

6.  That,  when  the  menses  are  suppressed,  they  cannot  be  restored  by  inducing  ple- 
thora, noi  the  flow  bo  checked  by  blood-letting,  or  any  other  means  of  depletion.     Be- 
sides, no  vicarious  discharge  relieves  the  symptoms  of  suppression.     Do  not  these  facts 
very  unequivocally  proclaim  the  existence  of  a  secretory  function  ? 

Lastly,  That  the  menses  are  a  fluid  sui  generis,  or  at  least  varying  essentially  from 
blood ;  having  neither  its  colour,  nor  odour,  nor  coagulability,  and,  on  chemical  analysis, 
present  different  results.  Let  us  ask,  if  the  menstrual  fluid  be  not  blood,  what  is  it  ? 
To  the  objection,  which  has  sometimes  been  urged,  that  the  uterus  is  not  sufficiently 
glandular  for  the  office  alleged,  it  may  be,  I  think,  very  satisfactorily  replied,  that  there 
is  hardlv  a  viscus  or  surface  of  the  body,  which  is  not  competent  to  this  purpose.  It 
would  really  seem  that  no  operation  of  the  animal  economy  requires  a  less  complex  ap- 
paratus. Of  what,  indeed,  dors-  a  gland  consist,  except  a  congeries  of  vessels  i1  Even 
the  most  perfect  of  the  secretions  are  accomplished  by  this  simple  contrivance.  If  a 
few  vessels,  "  creeping  through  the  coax's  of  the  stomach,"  can  secrete  the  gastric 
liquor,  why  may  not  the  infinitely  more  glandular  organization  of  the  uterus  elaborate 
the  menstrual  fluid  ?  As  yet  we  know  of  no  glandular  structure  in  vegetables,  they  con- 
taining only  tubes  or  vessels,  through  which  the  fluids  circulate.  Notwithstanding, 
however,  the  want  of  glands,  we  find  the  sap  of  plants  converted  into  oil,  mucilage, 
acids,  &c.  No  stronger  proof  can  certainly  be  required  of  the  extreme  simplicity  of 
the  organs  by  which  the  secretory  transformations  are  effected. 

Who  originally  suggested  the  theory  of  secretion  we  have  not  been  able  to  ascertain. 
Ithasvery^enerally  been'ascribedto  the  celebrated  Mr.  Hunter;  but  the  evidence  of 
his  claims  to  it  is  exceedingly  slender.  The  only  trace  of  it,  which  we  can  discover  m 
his  writings,  is  a  vague  expression  in  a  paragraph  of  his  Treatise  on  the  Blood.  Atter- 
wards,  however,  he  furnished  an  extract  from  his  lectures  to  be  published  in  Johnson  s 
Midwiferv,  as  exhibiting  more  fully  his  notion  respecting  this  function.  Speaking  of  the 
death  of  "the  blood  from  lightening,  and  other  sudden  causes,  he  includes  the  catamenia 
amonq;  the  illustrations  of  his  reasonings.  "  The  blood  (says  he)  discharged  in  men- 
struation is  neither  similar  to  blood  taken  from  a  vein  of  the  same  person,  nor  to  that 
extravasated  by  an  accident  in  any  other  part  of  the  body;  but  is  a  species  of  blood 
clv*ne;ed  separated,  or  thrown  off  from  the  common  mass  by  an  action  of  the  vessels  ot 
the  uterus,  in  a  process  similar  to  secretion,  by  which  action  the  blood,  having  lost  its  hv- 
int?  principle,  does  not  coagulate,"  &c. 

"The  blood  (says  Holler)  is  brought  into  the  womb  in  greater  quantity,  and  more 
quickly,  through  its  lax  and  ample  arteries,  and  on  account  of  the  rigidity  and  narrow- 
ness of  the  veins  it  returns  with  difficulty.—  Chapman. 

*  They  are  likewise  given  off,  in  great  numbers,  from  the  cerebral  nerves  :  thus,  the 


215 

to  each  of  them  a  peculiar  sensibility,  by  means  of  which  they  discover  in 
the  blood  which  the  vessels  bring  to  them,  the  materials  of  the  fluid  which 
they  are  destined  to  secrete,  and  these  they  appropriate  to  themselves  by  a 
real  selection.  Besides,  the  nerves  communicate  to  them  a  peculiar  mode 
of  activity,  the  exercise  of  which  makes  those  separated  elements  undergo 
a  peculiar  com  position,  and  bestows  on  the  fluid  which  is  the  product  of  it, 
specific  qualties  always  bearing  a  certain  relation  to  the  mode  of  action  of 
which  it  is  the  result.  Thus,  the  liver  seizes  the  materials  of  the  bile  con- 
tained in  the  blood  of  the  vena  portae,  elaborates,  combines  those  materials, 
and  converts  them  into  bile,  an  animal  fluid,  distinguishable  by  peculiar  cha- 
racteristic properties,  subject  to  certain  variations,  according  as  the  blood 
contains  in  different  proportions,  the  elements  of  which  it  is  formed;  ac- 
cording as  the  gland  is  more  or  less  disposed  to  retain  them,  and  to  blend 
them  together.  The  qualities  of  the  bile  depending  on  a  concurrence  of 
all  these  circumstances, must  present  as  many  differences  as  the  blood  which 
contains  its  elements,  and  the  liver  may  present  varieties,  with  regard  to 
the  composition  of  the  former,  and  to  the  activity  of  the  latter.  Hence 
the  many  changes  in  the  qualities  of  the  fluid,  the  slightest  of  which,  not 
affecting  the  health,  escape  observation,  while  those  changes  which  are 
greater,  and  which  disorder  the  natural  order  of  the  functions,  show  them- 
selves in  diseases  of  which  they  maybe  considered  as  the  effect  and  at  other 
times,  as  the  cause.  These  changes  in  the  condition  of  the  bile  (and  what  is 
now  said  applies  to  almost  all  the  secretions  of  the  animal  economy),  these 
changes  are  never  carried  so  far  as  to  make  the  bile  lose  all  its  distinguish- 
ing characters,  it  never  takes  on  the  qualities  belonging  to  another  fluid, 
it  never  resembles  semen,  urine,  or  saliva. 

The  secretory  glands  do  not  carry  on  an  uninterrupted  action ;  almost  all 
of  them  are  subject  to  alternate  action  and  repose:  all  as  Bordeu  observed, 
sleep  or  waken,  when  irritation  affects  them,  or  their  neighbouring  parts, 
and  determines  their  immediate  and  sympathetic  action.  Thus,  the  saliva 
is  more  plentifully  secreted  during  mastication  ;  the  gastric  juice  is  poured 
within  the  stomach,  only  while  digestion  is  going  on  ;  when  the  stomach 
is  emptied  of  food,  the  secretion  ceases,  and  is  renewed^  when  the  pre- 
sence of  food  again  excites  a  sufficient  degree  of  irritation*.  The  bile 
flows  more  abundantly,  and  the  gall  bladder  frees  itself  of  that  which  it 
contains,  while  the  duodenum  is  filled  by  the  chymous  mass. 

When  a  secretory  organ  is  in  action,  it  determines  the  motion  of  the 
parts  in  its  vicinity,  or,  as  Bordeu  expresses  it,  within  its  atmosphere. 
A  part  is  said  to  belong  to  the  department  of  a  certain  gland,  when  it  par- 
takes in  the  motion  affecting  the  latter,  during  the  process  of  secretion, 
or  when  it  is  employed  in  functions  subservient  lo  that  of  the  gland  ; 
these  departments  are  of  different  extent,  according  to  the  importance  of 
the  action  of  the  gland.  Thus,  one  may  say  that  the  spleen  and  most  of 
the  viscera  of  the  abdomen  are  of  the  department  of  the  liver,  since  they 


salivary  glands  receive  from  the  seventh  paii>  from  the  maxillary  nerve  from  the  fifth 
pair,  and  from  the  cervical  nerves,  a  number  of  nerves  that  will  "appear  very  great,  if 
the  bulk  of  those  glands  is  considered — Author's  J\ote. 

*  This  is  very  contrary  to  the  observations  of  Wilson  Philip,  whose  experiments  show, 
that  the  secretion  of  the  gastric  fluid  precedes  the  reception  of  food,  and  may  be  es- 
teemed the  immediate  cause  of  the  sensation  ot'bunger.  According1  to  him,  the  secre- 
tion is  suspended,  as  soon  as  the  stomach  receives  a  certain  quantity  of  food.  See  his 
Treatise  on  Pevers,  appendix  to  Vol.  2.  and  ius  Inquiries  on  Indigestion.— Godman, 


receive  from  it,  the  biood  ou  which  they  are  to  act.  The  liver  is  also- 
comprised  in  the  sphere  of  activity  of  the  duodenum,  since  the  distension 
of  that  intestine  irritates  it,  determines  a  more  copious  flow  of  its  fluids, 
and  a  more  abudant  secretion  of  bile. 

C.  The  blood  which  is  sent  to  a  secretory  gland,  before  reaching  it,  un- 
dergoes preparatory  changes,  which  dispose  it  to  furnish  the  materials  of 
the  fluid  which  is  to  be  separated  from  it.  We  have  seen,  in  treating  of 
digestion,  how  the  blood  which  the  vena  portae  sends  to  the  liver,  is  fit 
for  the  secretion  of  bile.  There  can  be  no  doubt,  that  the  portion  of 
blood  which  it  carries  to  the  testicles,  by  the  long,  slender,  and  tortuous 
spermatic  arteries,  undergoes  changes*,  which  bring  it  nearer  to  the  se- 
minal fluid. 

The  rapidity  with  which  the  blood  flows  into  an  organ,  the  length,  the 
diameter,  the  direction,  the  angles  of  its  vessels,  the  arrangement  of  their 
extreme  ramifications,  which  may  be  stellated,  as  in  the  liver,  in  fasciculi, 
as  in  the  spleen,  convoluted,  as  in  the  testicles,  Sec.  are  circumstances 
which  should  be  taken  into  account  in  the  study  of  each  secretion,  since 
all  have  some  influence  on  the  nature  of  the  fluid  secreted,  and  on  the 
manner  in  which  the  secretion  is  effected. 

The  fluid  which  lubricates  the  whole  extent  of  the  moveable  surfaces 
by  which  the  bones  of  the  skeleton  are  articulated  together,  is  not  exclu- 
sively prepared  by  the  membranous  capsules  which  envelope  the  articu- 
lations. A  number  of  reddish  coloured  cellular  substances,  placed  in 
their  vicinity,  co-operate  in  the  secretion.  Though  these  parts,  which 
were  long  considered  as  synovial  glands,  do  not  completely  resemble  the 
conglomerate  glands,  and  although  no  glandular  bodies,  nor  excretory 
ducts,  can  be  demonstrated  in  them,  they  cannot,  however,  but  be  consi- 
dered as  fulfilling,  to  a  certain  degree,  the  same  functions,  and  one  must 
admit  that  they  are  of  some  utility,  in  the  secretion  of  the  synovia.  They 
are  always  met  with;  their  extent  and  bulk  are  always  proportioned  to 
the  extent  of  the  auricular  .surfaces,  and  to  the  frequency  of  motion  in 
the  joints  near  which  they  are  situated.  They  are  found  in  all  animals  ; 
pale  and  light  coloured  in  those  which  have  been  long  at  rest;  red,  high- 
ly vascular,  and  bearing  the  marks  of  a  kind  of  inflammatory  diathesis, 
in  those  which  have  been  compelled  to  violent  exercise,  as  the  oxen  which 
are  brought  to  Paris  from  distant  provinces,  and  the  wild  animals  which 
have  been  hunted.  In  anchylosis,  they  are  less  red  and  of  greater  con- 
sistence, than  in  a  healthy  state. 

When,  from  the  irritation  attending  friction,  the  fluids  are  determined 
towards  an  articulation  which  is  in  motion,  do  they  not  then,  by  passing 
through  those  glandulo-cellular  bodies,  undergo  a  peculiar  modification 
which  renders  them  fitter  for  the  secretion  of  synovia.  This  would  not 
be  the  only  instance,  in  the  human  body,  of  parts  whose  action  is  but  se- 
condary and  connected  with  that  of  other  organs  principally  engaged  in  a 
secretion  whose  materials  are  contained  in  the  blood  which  passes  through 
them.  It  will  be  urged,  no  doubt,  that  this  preparatory  apparatus  is  not 
met  with  in  the  neighborhood  of  the  great  cavities ,  but  it  should  be  re- 


*  By  this  loose  expression  one  might  be  induced  to  suppose  that  the  changes  here  al- 
luded to  were  spontaneous,  or  chemical.  It  should  have  been  said  that  the  peculiar  or- 
ganization of  the  spermatic  vessels  seems  designed  to  produce  the  changes  which  bring 
the  blood  nearer  in  character  to  the  Seminal  fluid. — Godman, 


217 

collected,  that  the  chemical  composition  and  the  uses  of  the  synovia,  are 
not  precisely  the  same  as  those  of  the  fluids  secreted  by  the  pleura  or  the 
peritoneum ;  and  that,  besides,  the  analogy  between  two  objects,  does 
not  constitute  their  identity.  The  human  mind  being  naturally  indolent, 
loves  to  discover  analogies  that  support  it  in  its  weakness,  and  that  may 
save  it  the  trouble  of  seeking  points  of  difference.  I  am  aware,  that  to 
prove  that  the  mechanism  of  the  synovial  secretion,  which  exactly  resem- 
bles that  of  the  fluid  which  moistens  the  inside  of  the  great  cavities,  re- 
quires like  it  but  a  simple  membranous  apparatus,  it  is  customary  to  re- 
peat, in  every  possible  way,  that  Nature  is  scanty  in  her  means,  and  la- 
vish in  her  results;  that  she  produces  from  the  same  cause,  a  variety  of 
different  effects,  Sec.  but  without  pointing  out  the  manifest  absurdity  of 
admitting  metaphysical  arguments  in  the  natural  sciences,  is  it  not  much 
more  reasonable  to  acknowledge  with  philosophers,  that  the  primitive 
cause  may  vary  in  many  ways,  and  that  its  innumerable  modifications, 
whence  arise  the  difference  in  the  effects,  exceed  the  limited  powers  of 
our  understanding? 

CI.  When  a  gland  is  irritated,  it  becomes  a  centre  of  fluxion,  towards 
which  the  fluids  are  determined  from  every  part;  it  swells,  hardens,  con- 
tracts, is  in  a  kind  of  state  of  erection,  bends  on  itself,  and  acts  on  the 
blood  conveyed  by  its  vessels.  Secretion,  depending  on  the  peculiar  and 
inherent  power  of  the  glandular  organ,  is  promoted  by  the  slight  motion 
which  it  receives  from  the  neighbouring  muscles.  The  gentle  pressure 
of  those  parts  on  the  glandular  organ,  is  sufficient  to  keep  up  their  excite- 
ment, atid  to  assist  in  the  separation  and  excretion  of  the  fluid.  Bordeu, 
in  his  excellent  work  on  the  glands  and  on  their  action,  has  shown  that  it 
is  not  in  consequence  of  the  compression  which  is  produced  on  them  by 
the  neighbouring  muscles,  that  they  part  with  the  fluid  they  have  pre- 
pared, that  physiologists  were  therefore  very  much  in  the  wrong,  in  say- 
ing, that  the  excretion  of  a  fluid  consisted  merely  in  its  expression,  and 
in  comparing,  under  that  point  of  view,  the  glands  to  sponges  soaked 
with  a  fluid  which  they  give  out,  on  being  squeezed. 

The  excretory  ducts  of  organs  absorb  or  reject  the  secreted  fluid,  ac- 
cording as  it  affects  their  inhalent  mouths  :  these  canals  partake  in  the 
convulsive  state  of  the  gland,  undergo  a  degree  of  erection,  and  contract 
on  the  fluid  to  expel  it.  Thus,  the  saliva  starts  from  the  parotid  duct, 
at  the  sight,  or  in  the  recollection  of  food  that  has  been  longed  for;  thus, 
the  vesiculae  seminales  and  the  urethra  (for  the  reservoirs  in  which  the 
fluids  lie  some  time  before  being  expelled,  may  be  considered  as  forming 
apart  of  the  excretory  ducts),  contract,  become  straighter,  and  lengthen 
themselves  to  force  to  a  distance  the  spermatic  fluid. 

The  thin  and  transparent  ureters  in  fowls  have  been  seen  to  contract 
on  the  urine,  which,  in  these  animals,  concretes  on  the  slightest  stagna- 
tion. 

After  remaining  a  certain  length  of  time,  in  that  state  of  excitement, 
the  glands  relax,  their  tissue  collapses,  the  juices  cease  to  be  conveyed 
to  it  as  plentifully,  they  fall  into  a  state  of  repose  or  sleep,  which  restores 
their  sensibility,  exhausted  by  too  much  action.  It  is  well  known,  that  a 
gland  over-stimulated,  becomes,  like  any  other  part,  insensible  to  the 
stimulus,  the  continued  appplication  of  which  parches  and  exhausts  it. 

From  what  has  just  been  said  relative  to  the  mechanism  of  the  secretions, 
it  will  be  seen  that  this  function  may  be  divided  into  three  very  distinct  pe- 
riods ;  IstMhat  of  irritation,  characterised  on  the  growth  of  the  vital  pro- 

2  E 


218 

perties,  and  by  the  more  copious  accession  of  the  fluids,  the  necessary 
consequence  of  that  excitement;  2nd.  the  action  of  the  glands;  that  is, 
its  secretion,  properly  so  called;  3d.  lastly,  the  action  by  which  the  organ 
parts  with  the  fluid  which  it  has  prepared:  this  is  the  last  process,  it  is 
called  excretion,  and  is  promoted  by  the  action  of  the  neighbouring  parts. 
The  determination  of  fluids  to  the  part,  the  secretion  and  excretion  suc- 
ceed each  other;  they  are  preceded  by  the  excitement,  which  is  the  pri- 
mary cause  of  all  the  subsequent  phenomena.  The  circulation  is,  at  first, 
excited,  more  blood  is  sent  into  the  part,  and  penetrates  into  the  tissue  of 
the  gland.  Dr.  Murat  has  had  occasion  to  open  a  considerable  number 
of  old  men,  who  died  at  the  Bicetre,  and  who  were  known  to  be  great 
smoakers  of  tobacco.  He  uniformly  observed,  that  their  parotid  glands, 
continually  called  into  action  by  that  habit,  were  larger  than  in  those 
who  were  not  given  to  it,  and  that  they  were  remarkably  red,  in  conse- 
quence of  the  blood  with  which  they  were  constantly  injected. 

What  is  the  office  of  the  nerves  in  the  act  of  secretion?  what  share  has 
the  nervous  influence  in  the  elaboration  of  the  fluids  furnished  by  the 
glandular  organs?  All  the  glands  which  receive  their  nerves  from  the 
system  of  animal  life,  such  as  the  lachrymal  and  salivary  glands,  appear, 
in  certain  cases,  to  receive,  from  the  brain,  the  secretory  excitation.  The 
influence  of  the  imagination  is  sufficient  to  determine  it;  thus,  we  shed 
involuntary  tears,  when  the  mind  is  taken  up  with  painful  thoughts;  and 
the  mouth  fills  with  saliva,  on  the  recollection  of  a  grateful  meal*.  In 
such  cases,  the  influence  of  the  nerves  on  the  process  of  secretion,  is  in- 
disputable: it  is  not  so,  however,  with  the  conglomerate  glands  that  re- 
ceive their  nerves  from  the  great  sympathetics.  The  secretion  of  the 
kidneys,  of  the  liver,  and  of  the  pancreas,  appears  less  influenced  by  affec- 
tions of  the  mind;  the  brain,  besides,  has  no  immediate  connexion  with 
these  glands;  their  nerves  are,  almost  entirely,  given  off  by  the  great 
sympathetics;  the  kidneys  in  particular,  receive  no  nerves  from  the  brain, 
or  from  the  spinal  marrow ;  hence  the  secretion  of  urine  seems,  more 
than  any  other,  to  be  independent  of  the  nervous  influencef. 


*  These  glands,  viz.  the  lachrymal  and  salivary,  receive  nerves  both  from  the  nearest 
ganglions,  and  from  the  nerves  of  voluntary  motion  :  the  former  set  of  nerves  mos.t  pro- 
bably enables  them  to  perform  their  ordinary  functions,  the  latter  excites  or  reinforces 
these  functions  whenever  the  mind  is  under  certain  impressions. 

•f-  Although  these  organs  are  not  directly  influenced  by  the  cerebral  and  spinal  nerves, 
it  cannot  be  satisfactorily  denied  that  the  ganglial  nerves,  which  are  so  abundantly  dis- 
tributed to  the  blood-vessels  supplying  these  organs,  bestow  on  these  vessels  that  pe- 
culiar influence  which  determines  the  nature  and  quantity  of  the  secretion ;  for  how  can 
we  suppose  the  capillary  tubes,  through  which  the  blood  flows,  to  be  able  to  secrete  a 
peculiar  fluid  of  themselves,  without  resorting  to  the  position  that  the  nerves,  which  so 
abundantly  supply  the  ramifications  of  the  blood-vessels,  and  the  substance  of  the  se- 
creting organs,  actually  influence,  and,  through  the  medium  of  those  vessels,  even 
produce  the  secretions  in  question  ?  Are  not  these  nerves  requisite  to  the  vital  actions 
of  the  viscera  which  they  supply?  Do  we  know  an  animal  that  does  not  possess  them 
as  a  most  essential  part  of  its  organization  ?  And  can  we  suppose  that  they  are  distri- 
tributed  in  so  abundant  a  manner  to  the  vessels  of  a  secreting  organ,  without  perform- 
ing  a  most  requisite  part  in  the  production  of  the  fluids  which  that  organ  secretes  ?  A 
close  investigation  ot  the  structure  of  the  secreting  viscera  and  surfaces  shows  that  their 
blood-vessels,  which  bear  in  their  number  and  size  a  close  relation  to  the  extent  of  func- 
tion which  such  viscera  individually  perform,  are  more  amply  supplied  with  this  class  of 
nerves  than  the  vessels  of  any  other  of  the  animal  textures :  indeed  every  important  se- 
creting gland  has  a  distinct  g'anglion,  or  plexus  of  these  nerves  surrounding  the  blood- 
vessels which  belong  to  it ,  but  more  especially  the  arteries,  and  some  of  these  organs 


This  great  number  of  secretory  organs,  constantly  engaged  in  separating 
various  secretions  from  the  mass  of  the  fluids,  would  soon  exhaust  it,  if 
the  calculations  of  physiologists  of  the  amount  of  what  a  gland  is  capable 
of  secreting,  were  not  manifestly  exaggerated.  In  fact,  if  w,e  admit,  with 
Haller,  that  the  mucous  glands  of  the  intestinal  canal  secrete,  in  twenty- 
four  hours,  eight  pounds  of  mucous;  that,  in  the  same  lapse  of  time,  the 
kidneys  secrete  four  pounds  of  urine,-  that  the  same  quantity  is  lost  by  the 
insensible  perspiration;  and  again,  as  much  by  the  pulmonary  exhalation; 
there  will  be  lost,  daily,  twenty  pounds  of  fluids,  almost  entirely  excre- 
mentitious;  for  we  do  not  include  in  that  calculation  the  bile,  the  tears, 
nor  the  saliva  and  pancreatic  fluid,  which,  in  part,  returns  into  the  blood 
after  being  separated  from  it;  nor  the  serum  which  moistens  tl|e  internal 
surface,  and  which  is  purely  recrementitious. 

This  exaggeration,  in  the  calculations  of  the  fluids  which  ,are  daily- 
poured  out  by  the  different  emunctories,  is  to  be  attributed  to  the%:ircum- 
stance  of  having  taken  the  maximum  of  each  secretion,  without  consider- 
ing that  they  mutually  supply  each  other;  so  that,  when  less  urine  is  void- 
ed, the  quantity  of  perspiration  is  greater,  and  vice  versa.  It  is  very 
well  known,  that  a  violent  diarrhea  is  frequently  the  consequence  of  sud- 
den cold  applied  io  the  skin ;  the  fluids  at  once  repelled  towards  the  in- 
testiual  canal,  having  to  pass  through  the  mucous  glands  whose  action  is 
greatly  increased. 

CII.  It  has  been  customary  to  enumerate,  among  the  glands,  certain 
bodies  which  have  truly  a  glandular  appearance;  but  the  uses  of  which 
are  yet  unknown.  Thus,  the  thyroid  and  thymus  glands,  which  are  pa- 
renchymatous  organs  destitute  of  excretory  ducts,  though  receiving  many 
vessels  and  some  nerves,  do  not  appear  to  secrete  any  fluid.  But  may  not 
the  blood,  which  is  conveyed  so  plentifully  to  the  thyroid  gland,  undergo 
nevertheless  certain  changes,  though  we  may  not  be  able  to  discover 
what  they  are?  Besides,  may  not  the  lymphatics  perform  the  office  of 
excretory  ducts,  and  convey  back  again  immediately  into  the  mass  of  the 
blood,  the  fluid  which  has  undergone  changes  in  the  glandular  body?  The 
capsulse  renales  are  in  the  same  condition:  they  have,  however,  in  addi- 
tion, an  internal  reservoir,  a  kind  of  lacuna,  whose  parietes  are  smeared 
with  a  viscid  and  brown-coloured  substance  secreted  Ay  the  capsule,  and 
which  doubtless  is  conveyed  into  the  mass  of  the  bipod  by  the  lymphatics 
arising  from  the  parietes  of  its  internal  cavity. 

CHI.  Of  the  secretion  ofadeps  within  the  cellular  tissue.  This  soft  tissue, 
which  is  diffused  over  the  whole  body,  and  a#>rds  a  covering  to  all  our 
organs,  is  of  use  not  merely  in  separating  ^em  from  one  another,  and 
connecting  together  the  different  parts;  it  j/ besides,  the  secretory  organ 
of  the  adipose  substance,  a  semi-concrete/oily,  animal  substance,  which 
is  found,  in  almost  every  part  of  the  bo/y,  deposited  in  its  innumerable 
cells.  The  membranous  parietes  of  these  small  cellular  cavities  are  sup- 
plied by  numerous  minute  arteries,  i/i  which  the  adeps  is  separated;  it  is 
conveyed  by  its  specific  light  weight  to  the  circumference  of  the  column 
of  blood  in  the  vessels,  and  transudes  through  the  pores  in  their  parietes. 
Its  quantity  and  consistence  vary,  in  different  parts  of  the  body,  and  in 


have  both  a  large  plexus  of  nerves  and  a  ganglion,  whence  their  nerves  are  exclusively 
derived,  arid  which  appear  to  be  entirely  devoted  to  the  functions  of  the  viscus,  whose 
blood-vessels  they  plentifully  supply.  See,  on  this  subject,  the  APPENDIX,  Notes  H, 
A,  A,  and  those  on  Digestion,  Sac.-*- Copland. 


different  persons:  there  is  situated  below  the  skin  a  thick  layer  of  cellu- 
lar substance  (fatty  pannick;')  it  is  found,  in  considerable  quantity,  be- 
tween the  interstices  of  the  muscles,  along  the  blood-vessels,  near  the 
articulations,  and  in  the  vicinity  of  Certain  organs,  as  the  eyes,  the  kid- 
neys, and  the  breasts.  That  which  fills  the  bottom  of  the  orbit,  and 
which  surrounds  the  eye-ball,  is  softish  and  almost  fluid;  that  which  en- 
velopes the  kidneys  and  the  great  joints  is,  on  the  contrary,  of  the  con- 
sistence of  suet.  Between  these  two  extremes  there  are  many  gradations, 
and  it  may  be  said,  that  the  animal  in  question,  is  not  exactly  the  same 
in  any  two  different  parts  of  the  body.  The  high  temperature  of  the  hu- 
man body  maintains  it  in  a  state  of  semi-fluidity,  as  may  be  observed  in 
surgical  operations. 

In  some  parts,  it  is  even  absolutely  fluid,  but  its  nature  is  then  observed 
to  be  greatly  changed;  it  no  longer  contains  any  oily  substances,  and  differs 
but  littte  Yrom  a  mere  aqueous  gelatine.  Thus,  the  fluid  in  the  cellular 
tissue  of  the  eye-lids,  of  the  scrotum,  Sec.  has  been  considered  by  several 
physiologists,  as  absolutely  different  from  fat.  It  may  not  be  amiss  to 
observe,  that  the  lamina  of  the  cellular  tissue,  in  such  circumstances, 
yield  more  readily  to  extension,  present  a  greater  surface,  form  mem- 
branous expansions^,  and  circumscribe  ceHs~of  considerable  size,  so  that 
the  differences  in  the  secretion,  perfectly  coincide  with  the  difference  of 
structure.  It  may  further^oe  observed,  that  the  functions  of  the  eye-lids 
and  of  the  penis  required  that  they  should  not  contain  any  fat.  Conside- 
rable deformity,  when  the  person  grew  fat,  would  have  been  the  conse- 
quence of  the  increased  bulk  of  these  parts,  and  besides,  the  folds  of  the 
skin  would  not  have  that  free  motion  which  their  functions  require.  No 
real  adeps  is  ever  found  within  the  skull,  and  the  utility  of  this  condition 
is  very  obvious.  To  how  many  dangers  would  not  life  have  been  exposed, 
if  a  fluid  so  varying  in  quantity,  and  the  amount  of  which  may  be  trebled, 
in  a  very  short  lapse  of  time,  had  been  deposited  into  a  cavity  accurately 
filled  by  an  organ  which  is  affected  by  the  slightest  compression  ? 

In  an  adult  male,  of  moderate  corpulence,  the  proportion  of  adeps  is 
about  one-twentieth  of  the  weight  of  the  whole  body;  it  is  greater,  in 
proportion,  in  children  and  in  females  ;  for,  its  quantity  is  always  relative 
to  the  energy  of  the  functions  of  assimilation.  When  digestion  and  ab- 
sorption are  performed  with  great  activity,  fat  accumulates  within  the 
cellular  substance:  atd  if  it  be  considered  that  it  is  but  imperfectly  ani- 
malized,  that  it  bears  ttie  most  striking  analogy  to  the  oils  extracted  from 
plants;  that  it  contains  \«ry  little  azote,  and  much  hydrogen  and  carbon, 
like  all  other  oily  substances,  since  on  distillation  it  is  decomposed,  and 
yields  water  and  carbonic  a*id,  with  a  very  small  quantity  of  ammonia; 
that  its  proportions  are  very  variable,  and  may  be  considerably  increased 
or  diminished,  without  manifestly  impairing  the  order  of  the  functions; 
that  animals  that  spend  a  great  ^art  of  their  life  without  eating,  seem  to 
exist  during  that  torpid  state,  on  the  fat  which  they  have  previously  ac- 
cumulated in  certain  parts  of  their  body*;  one  will  be  led  to  think,  that 


*  Marmots  and  dormice  become  prodigiously  fat  during  the  autumn;  they  then  take 
to  their  holes  and  live  in  them  during  the  six  winter  months,  on  the  fat  which  is  accu- 
mulated in  all  their  organs.  There  is  most  fat  collected  in  the  abdomen,  in  which  the 
epiploon  forms  masses  of  a  considerable  size.  When,  in  the  spring,  their  torpor  ceases, 
and  they  awaken  from  their  sleep,  they  are  for  the  most  part,  exceedingly  emaciated. — 
Author's  Note, 


221 

the  state  of  fat  is,  to  a  portion  of  the  nutritive  matter  extracted  from  the 
food,  a  kind  of  intermediate  state,  through  which  it  has  to  pass  before  it 
can  be  assimilated  to  the  animal  whose  waste  it  is  destined  to  repair. 
Animals  which  live  on  grain  and  vegetables,  are  always  fatter  than  those 
•which  live  exclusively  on  flesh.  Their  fat  is  consistent  and  firm,  while 
that  of  carnivorous  animals  is  almost  completely  fluid. 

A  corpulent  man,  on  having  his  diet  suddenly  reduced,  sensibly  be- 
comes thinner,  in  a  very  short  time:  the  bulk  and  weight  of  his  body 
diminish,  from  the  absorption  of  the  fat  which  supplies  the  deficient 
quantity  of  blood.  Adeps  may,  therefore,  be  considered  as  a  substance 
in  reserve,  by  means  of  which,  notwithstanding  the  small  quantity  of  food 
and  its  want  of  nutritious  qualities,  Nature  finds  wherewith  to  repair  the 
daily  waste. 

CIV.  The  use  of  adeps  is  not,  as  has  been  stated,  on  the  authority  of 
Macquer,  to  absorb  the  acids  that  are  formed  in  the  animal  economy; 
that  which  is  obtained  from  it,  by  distillation,  (the  sebaceous  add]  is  anew 
product  formed  by  the  combination  of  the  atmosphere  with  the  hydro- 
gen, the  carbon,  and  the  small  quantity  of  azote  which  it  contains.  The 
small  quantity  of  this  last  substance  nearly  constitutes  it  a  vegetable 
acid.  Fat  has  a  considerable  affinity  for  oxygen,  and  by  combining  with 
it,  turns  rancid,  after  remaining  some  time  exposed  to  the  air.  It  de- 
prives metallic  oxides  of  a  part  of  their  oxygen,  and  likewise,  on  being 
triturated  with  metallic  substances,  promotes  their  oxidizement.  In  pro- 
portion as  it  absorbs  oxygen,  its  density  increases :  thus  oils  become 
concrete  by  combining  with  oxygei,  and  fat  acquires  a  consistence  almost 
equal  to  that  of  wax,  which  is  itself  a  fatty  substance  highly  oxidized. 

Besides  the  principal  use  which  we  have  assigned  to  adeps,  and  ac- 
cording to  which  the  cellular  system  may  be  looked  upon  as  a  vast  reser- 
voir, in  which  there  is  deposited  a  considerable  quantity  of  nutritive  and 
semi-animalized  matter,  this  fluid  answers  several  purposes  of  secondary 
^utility.  It  preserves  the  body  in  i;s  natural  temperature,  being,  as  well 
as  the  tissue  of  the  cells  in  which  it  is  contained,  a  very  bad  conductor  of 
heat.  Persons  who  are  excessively  corpulent,  scarcely  feel  the  most 
severe  cold;  animals  which  inhabit  northern  climates,  besides  being 
clothed  in  a  thick  fur,  are  likewise  provided  with  a  considerable  quantity 
of  fat.  The  fishes  of  the  frozen  seas,  the  cetaceous  animals  which  sel- 
dom go  far  from  the  polar  regions,  all  kinds  of  whales  are  covered  with 
fat,  and  have  likewise  a  considerable  quantity  within  their  bodies.  By 
its  unctuous  qualities,  fat  promotes  muscular  contraction,  the  motion  of 
the  different  organs,  the  free  motion  on  each  other  of  the  different  sur- 
faces; it  stretches  and  supports  the  skin,  fills  vacuities,  and  gives  to  our 
limbs  those  rounded  outlines,  those  elegant  and  graceful  forms  peculiar 
to  the  female  body.  Lastly,  it  envelopes  and  covers  over  the  extremities 
of  the  nerves,  diminishes  their  susceptibility,  which  is  always  in  an  in- 
verse ratio  of  the  corpulency ;  which  induced  a  physician  of  merit  to  say, 
that  the  nervous  tree,  planted  in  the.  adipose  and  cellular  substance,  suf- 
fers, when  from  the  collapse  and  the  removal  of  that  tissue,  its  branches 
are  exposed,  in  an  unprotected  state,  to  the  action  of  external  causes,  as 
injurious  to  them  as  the  rays  of  the  sun  to  a  plant  torn  from  its  native 
soil.  It  is,  in  fact,  observed  that  nervous  people  are  exceedingly  thin, 
and  have  an  excessive  degree  of  sensibility.  Too  much  fat,  however,  is 
as  injurious  as  too  small  a  quantity  of  it.  I  have  seen  several  persons 
whose  obesity  was  such,  that  besides  being  completely  incapable  of 


£22 

taking  the  slightest  exercise,  they  were  in  great  danger  of  suffocation, 
Respiration  in  such  persons  is  at  times  interrupted  by  deep  sighs,  and 
their  heart,  probably  overloaded  with  fat,  expels  with  difficulty  the  blood 
within  its  cavities. 

CV.  According  to  modern  chemists,  the  use  of  fat  is  to  take  from  the 
system  a  part  of  its  hydrogen.  When  the  lungs  or  liver  are  diseased, 
when  respiration  or  the  biliary  secretion  do  not  carry  out  of  the  system, 
a  sufficient  quantity  of  that  oily  and  inflammable  principle,  fat  forms  in 
a  greater  proportion.  They  appeal  to  the  result  of  the  experiment  of 
shutting  up  a  goose,  whose  liver  is  to  be  fattened,  in  a  confined  cage, 
placed  in  a  hot  and  dark  situation,  and  in  gorging  it  with  paste,  of  which 
it  eats  the  more  greedily,  as  being  unable  to  stir,  it  gratifies  its  inclina- 
tion to  action,  by  exerting  the  organs  of  digestion.  Notwithstanding 
this  quantity  of  food,  the  bird  becomes  emaciated,  is  affected  with  a  kind 
of  marasmus,  its  liver  softens,  grows  fatter,  more  oily,  and  attains  an 
enormous  size. 

This  experiment,  and  many  other  facts,  prove,  that  the  secretions  from 
which  analogous  products  are  formed,  may  mutually  supply  each  other  ; 
but  can  we  admit  the  chemical  theory  bf  the  use  of  1'at  when  we  recollect 
that  frequently,  in  the  most  corpulent  persons,  respiration  and  the  secre- 
tion of  bile  are  performed  with  great  freedom  and  with  no  difficulty; 
while  the  difficult  respiration  attending  pulmonary  consumption,  and  the 
difficult  flow  of  the  bile  from  an  obstruction  of  the  liver,  are  always  ac- 
companied with  complete  marasmus. 


Whatever  moderates  the  activity 
bring  on  adipose  plethora.  Thus  an  i 
profuse  bleedings,  castration,  sometir 
•which  the  cellular  tissue  appears  affe 
actual  adipose  infiltration,  which  ma) 
rise  to  tumours  called  steatomatous. 


the  circulatory  system,  tends  to 
active  state  of  the  mind  and  body, 
es  induce  obesity,  an  affection  in 
ed  with  atony,  and  undergoes  an 
be  compared  to  that  which  gives 
f  the  energy  of  the  heart  and  arte- 


ries is  too  great,  emaciation  is  always  the  consequence;  when,  on  the  con- 
trary, the  sanguineous  system  is  languid,  there  is  formed  a  merely  gela- 
tinous fat,  and  the  corpulence  is  a  mere  state  of  bloatedness. 

This  incompletely  formed  fluid,  wl^ch  distends  the  parts  in  persons  of 
a  leucophlegmatic  habit,  is  but  an  ifnperfect  kind  of  fat;  it  resembles 
the  marrow  or  the  medullary  juice  which  is  merely  a  very  liquid  fat, 
whose  consistence  diminishes  when  animals  become  lean.  Inclosed  with- 
in the  cells  of  the  osseous  tissue,  in  cavities  whose  sides  cannot  collapse, 
and  whose  dimensions  must  always  remain  the  same,  the  marrow  of  which 
they  are  never  free,  is  of  different  degrees  of  density;  and  what  authors 
say  of  its  diminished  quantity,  must  be  understood  as  applying  to  the  di- 
minution of  its  consistence. 

CVI.  The  secretion  of  the  marrow  is,  like  that  of  the  fat,  a  mere  arte- 
rial transudation  ;  it  is  performed  fyy  the  medullary  membrane,  which  is 
thin,  transparent,  and  cellular,  which  lines  the  inside  of  the  central  cavity 
of  the  long  bones,  and  extends  over  all  the  cells  of  their  spongy  substance. 
The  medullary  membrane,  when^n  a  healthy  state,  does  not  give  any 
marks  of  relative  sensibility.  In  all  the  amputations  I  have  performed, 
and  they  have  not  been  few:  in  all  the  operations  of  the  same  kind  at 
which  I  have  been  present,  whatever  the  bone  was,  whether  it  was  divi- 
ded near  a  joint  or  in  the  middle  of  its  body.  I  never  knew  the  patient 
complain  of  pain,  provided  the  limb  was  well  supported  by  the  assistants, 
and  provided  no  jerk  was  given  by  the  operator  himself.  In  that  opera- 


223 

tion,  the  pain  occasioned  by  the  division  of  the  skin  and  of  the  nerves, 
overcomes  every  other  pain,  and  I  have  always  seen  patients  impressed 
with  the  popular  prejudice,  and  expecting  anxiously  the  division  of  the 
bone,  feel  quite  free  from  pain,  as  soon  as  the  saw  had  begun  to  work. 
Nay,  several,  after  expressing,  by  their  cries,  the  most  acute  pain,  taking 
advantage  of  the  kind  of  ease  which  follows  the  division  of  the  flesh,  raise 
their  head,  and  look  on,  while  the  bone  is  being  sawn  through  ;  at  once 
actors  and  spectators  in  this  last  part  of  a  painful  and  bloody  operation. 

Yet  the  medullary  membrane,  the  injury  of  which  is  attended  with  no 
pain,  while  in  a  hea'lthy  state,  becomes  the  seat  of  the  most  exquisite  sen- 
sibility in  the  pains  in  the  bones,  which  mark  the  last  stages  of  the 
venereal  disease;  in  the  kind  of  conversion  into  flesh,  of  the  solid  bone^ 
known  by  the  name  of  spina  ventosa.  as  will  be  mentioned,  in  speaking 
of  the  uses  of  the  marrow,  in  the  chapter  on  the  organs  of  motion  and 
on  theii*  action. 


CHAPTER    VI. 


OF  NUTRITION. 

CVII.  ALL  the  functions  which  we  have  hitherto  made  the  object  of 
our  study;  digestion,  by  which  the  alimentary  substances  received  with- 
in the  body,  are  deprived  of  their  nutritive  parts;  absorption,  which  con- 
veys that  recrementitious  extract  into  the  mass  of  the  fluids  :  the  circu- 
lation, by  which  it  is  carried  to  the  parts  wherein  it  is  to  undergo  different 
changes;  digestion,  circulation,  absorption,  respiration,  and  the  secre- 
tions, are  but  preliminary  acts,  preparatory  to  the  more  essential  function 
treated  of  in  this  chapter,  and  the  consideration  of  which  terminates  the 
history  of  the  phenomena  of  assimilation. 

Nutrition  may  be  considered  as  the  complement  of  the  functions  of  as- 
similation. The  aliment,  altered  in  its  qualities,  by  a  series  of  decom- 
positions, animalized  and  rendered  similar  to  the  substance  of  the  being 
which  it  is  to  nourish,  is  applied  to  the  organs  whose  waste  it  is  to 
repair;  and  this  indentification  of  the  nutritive  matter  to  our  organs 
which  take  it  up  and  appropriate  it  to  themselves,  constitutes  nutrition. 
Thus,  there  is  accomplished  a  real  conversion  of  the  aliment  into  our 
own  substance. 

There  is  incessantly  going  on  a  waste  of  the  integrant  particles  of  the 
living  body,  which  a  multiplicity  of  circumstances  tend  to  carry  away 
from  it;  several  of  its  organs  are  constantly  engaged  in  separating  from 
it  the  fluids  containing  the  recrementitious  materials  of  its  substance 
worn  by  the  combined  action  of  the  air  and  of  caloric,  by  inward  friction, 
and  by  a  pulsatory  motion  that  detaches  its  particles. 

Alike,  therefore,  to  the  vessel  of  the  Argonauts,  so  often  repaired  in 
the  course  of  a  long  and  perilous  navigation,  that  on  her  return,  no  part 
of  her  former  materials  remained:  an  animal  is  incessantly  undergoing 


decay,  and  if  examined  at  two  different  periods  of  its  duration,  does  not 
contain  one  of  the  same  molecules.  The  experiment  performed  with 
madder,  which  dyes  red  the  bones  of  animals  among  whose  food  it  is 
mixed,  proves,  most  unquestionably,  this  incessant  decomposition  of  ani- 
mated and  living  matter.  One  has  only  to  interrupt,  for  a  sufficient 
length  of  time,  the  use  of  that  plant,  to  make  the  uniformly  red  colour 
assumed  by. the  bones  completely  disappear.  Now,  if  the  hardest  and 
most  solid  parts,  most  calculated  to  resist  decay,  are  undergoing  a  per- 
petual motion  of  decomposition  and  of  regeneration ;  there  can  be  no 
doubt,  that  this  motion  must  be  far  more  rapid  in  those  whose  power  of 
cohesion  is  much  inferior;  for  example,  in  the  fluids. 

Attempts  have  been  made  to  determine  the  period  a.t  which  the  body  is 
completely  renovated;  it  has  been  said,  that  an  interval  of  seven  years 
\vas  required  for  one  set  of  molecules  to  disappear  and  be  replaced  by 
others;  but  this  change  mj^st  go  on  more  rapidly  in  childhoofl  and  in 
youth.  It  must  be  slower  at  a  mature  age,  and  must  require  a  consider- 
able time,  at  a  very  advanced  period  of  life,  when  all  the  parts  of  the  body 
become,  in  a  remarkable  degree,  fixed  and  firm  in  their  consistence  while 
the  vital  powers  become  more  languid.  There  can  be  no  donbt,  that  the 
sex,  the  habit,  the  climate  in  which  we  live,  the  profession  we  follow,  our 
mode  of  life,  and  a  variety  of  other  circumstances,  accelerate  or  retard 
it;  so  that  it  is  absolutely  impossible  to  fix,  with  any  degree  of  certainty, 
its  absolute  duration. 

CVIII  The  parts  of  our  body,  in  proportion  as  they  undergo  decay, 
are  repaired  only  by  means  of  homogeneous  particles  exactly  like  them- 
selves :  were  it  otherwise,  their  nature,  which  always  remains  the  same, 
would  be  undergoing  perpetual  changes. 

When,  in  consequence  of  the  successive  changes  which  it  has  undergone 
from  the  action  of  the  organs  of  digestion,  of  absorption,  of  the  circu- 
lation, of  respiration,  and  of  secretion,  the  nutritive  matter  is  animalized 
or  assimilated  to  the  body,  which  it  is  to  nourish,  the  parts  which  it 
moistens,  retain  it  and  incorporate  it  to  their  own  substance.  This  nu- 
tritive identification  is  not  performed  alike  in  the  brain,  in  the  muscles, 
in  the  bones,  &c.  Each  of  them  appropriates  to  itself,  by  a  real  process 
of  secretion,  whatever  it  meets  with  fitted  for  its  nature,  in  the  fluids  con- 
veyed to  it  by  the  different  kinds  of  vessels,  but  especially  by  the  arteries, 
it  leaves  unaffected,  the  remaining  heterogeneous  particles.  A  bone  is 
a  secretory  organ,  around  which  the  phosphate  of  lime  is  deposited ;  the 
lymphatic  vessels  which,  in  the  process  of  nutrition,  perform  the  office 
of  excretory  ducts,  remove  that  saline  substance,  when  it  has  lain  suffi- 
ciently long  in  the  cells  of  its  tissue.  The  same  happens  to  the  muscles, 
•with  regard  to  fibrina,  and  to  albumen  with  regard  to  the  brain ;  every 
part  appropriates  to  itself,  and  converts  into  a  solid  form,  those  fluids 
\vhich  are  of  the  same  nature,  in  virtue  of  a  power  of  which  the  term  af- 
finity of  aggregation,  used  in  chemistry,  gives  an  idea,  and  of  which  it  is 
perhaps  the  emblem. 

The  nutrition  of  a  part  requires  that  it  should  be  possessed  of  sensibi- 
lity and  motion  ;  by  tying  the  arteries  and  nerves  of  a  part,  it  cannot  be 
nourished,  nor  can  it  live.  The  blood  which  flows  along  the  veins,  the 
fluid  conveyed  by  the  absorbents,  contain,  in  a  smaller  proportion  than 
arterial  blood,  vivifying  the  reparatory  particles.  It  is  even  commonly 
thought,  that  the  lymph  and  venous  blood  contain  no  directly  nutritive 
particles.  As  to  the  share  which  the  nerves  take  in  the  process  of  mi- 


225 

trition,  that  is  not  yet  completely  determined.  A  limb  that  is  para- 
lized,  by  the  division  or  tying  of  its  nerves,  or  by  any  other  affection,  some- 
times retains  its  original  size  and  plumpness ;  most  frequently,  however, 
though  perhaps  for  want  of  motion,  it  becomes  parched,  emaciated,  and 
skrinks  in  a  remarkable  degree. 

CIX.  We  should  be  enabled  to  understand  the  process  of  nutrition,  if 
after  having  accurately  determined  the  difference  of  composition  between 
our  food,  and  the  substance  itself  of  our  organs,  we  could  see  how  each 
function  robs  the  aliments  of  their  qualities,  to  assimilate  them  to  our 
own  bodies;  and  what  share  each  function  takes  in  the  transmutation  of 
the  nutritive  particles  into  our  own  substance.  To  illustrate  this  point, 
suppose  a  man  to  live  exclusively  on  vegetable  substances,  which,  in  fact, 
form  the  basis  of  our  food  ;  on  whatever  part  of  the  plant  he  may  live, 
whether  on  the  stem,  on  the  leaves,  on  the  blossoms,  on  the  seeds,  or  on 
the  root;  carbon,  hydrogen,  and  oxygen  enter  into  the  composition  of 
these  vegetable  substances,  which,  by  a  complete  analysis,  may  all  be 
resolved  into  water  and  carbonic  acid.  To  these  three  constituent  prin- 
ciples, there  is  frequently  united  a  small  quantity  of  azote,  of  salts,  and 
of  other  materials,  in  different  proportions.  If  then,  we  examine  the  na- 
ture of  the  organs  in  this  man  whose  food  is  entirely  vegetable,  it  will  be 
found  that  they  are  different  in  their  composition,  and  t'ar  more  animal- 
ized  than  that  kind  of  food;  that  azote  predominates,  though  the  vegeta- 
ble substance  contains  none  or  only  a  very  small  quantity,  that  new  pro- 
ducts, undistinguishable  in  the  aliments,  exist,  in  considerable  quantity, 
in  the  body  which  is  fed  on  them,  and  appear  produced  by  the  very  act 
of  nutrition. 

The  essence  of  this  function  is,  therefore,  to  make  the  nutritive  matter 
undergo  a  more  advanced  state  of  composition,  to  deprive  it  of  a  portion 
of  its  carbon  and  of  its  hydrogen,  to  make  azote  predominate,  and  to 
produce  several  substances,  which  did  not  exist  in  it  before.  All  living 
bodies  seem  to  possess  the  faculty  of  composing  and  decomposing  the 
substances  by  means  of  which  they  are  maintained,  and  to  form  new  pro- 
ducts: but  they  possess  it,  in  various  degrees  of  energy.  The  sea-weed, 
from  the  ashes  of  which  soda  is  obtained,  on  being  sown  in  a  box  of  soil, 
in  which  there  is  not  a  single  particle  of  that  alkali,  and  watered  with 
distilled  water,  will  for  a  time  continue  to  form  it,  as  if  it  had  grown 
on  the  sea-shore,  in  the  midst  of  marshes  constantly  inundated  by  salt 
and  brackish  water. 

Living  bodies  then,  are  real  laboratories,  in  which  are  carried  on 
combinations  and  decompositions  which  art  cannot  imitate  ;  bodies  that 
appear  to  us  simple,  as  soda  and  silex,  seem  to  be  formed  by  the  union 
of  their  constituent  particles:  while  other  bodies,  whose  composition  we  do 
not  understand,  undergo  an  irresistible  decomposition  :  hence,  one  may 
infer,  that  the  power  of  Nature  in  the  composition  and  decomposition  of 
bodies,  far  exceeds  that  of  chemistry*. 

Straw  and  cereal  plants  contain  an  enormous  quantity  of  silex,  even 
when  the  earth  in  which  they  grow  bus  been  carei'ully  deprived  of  its  si- 
liceous particles.  Oats,  particularly,  contain  a  considerable  quantity  of 
that  verifiable  earth  ;  the  ashes  obtained  by  burning  its  seed,  on  being 


*  To  the  substances  compounded  by  the  animal  body  may  be  added  lime,  which  is 
formed  in  quantities  far  exceeding  the  amount  taken  in  with  the  food.— Godman. 

2  F 


analyzed  by  means  of  the  nitric  acid,  were  found  by  M.  Vauquelin,  to 
contain  T6^  of  pure  silex  indissoluble  in  that  acid,  and  0,393  of  phos- 
phate of  lime  dissolved  in  it. 

The  excrements  of  a  hen,  fed,  for  ten  days,  on  oats  only,  on  being  cal- 
cined and  analyzed  by  the  same  chemist,  produced  twice  as  much  phos- 
phate and  carbonate  of  lime  as  was  contained  in  the  oats,  with  a  small 
deficiency  in  the  quantity  of  silex,  which  might  have  been  employed  in 
furnishing  the  excess  of  calcareous  matter;  a  transmutation  depending 
on  the  absorption  of  an  unknown  principle,  to  the  amount  of  nearly  five 
times  in  its  own  weight  *. 

CX.  A  substance  to  be  fit  for  our  nourishment,  should  be  capable  of 
decomposition  and  fermentation  ;  that  is,  capable  of  ^undergoing  an  in- 
ward and  spontaneous  change,  so  that  its  elements  and  relations  may  be 
altered.  This  spoutaneous  susceptibility  of  decomposition,  excludes  from 
the  class  of  aliments,  whatever  is  not  organized  and  is  not  a  part  of  a 
living  body,  thus,  mineral  substances  absolutely  resist  the  action  of  our 
organs,  and  are  not  convertible  into  their  own  substance.  The  common 
principle  extracted  from  alimentary  substances,  however  varied  they  may 
be,  the  aliment,  as  Hippocrates  terms  it,  is  most  probably,  a  compound 
highly  subject  to  decomposition  and  fermentation  ;  this  is  likewise,  the 
opinion  of  all  those  who  have  endeavoured  to  determine  its  nature.  Lorry 
thinks  it  a  mucous  substance  ;  Cullen  says  it  is  saccharine ;  Professor 
Halle  considers  it  as  an  hydro-carbonous  oxyde,  which  differs  from  the 
oxalic  acid,  only  in  containing  a  smaller  quantity  of  oxygen.  It  is  evi- 
dent, that  these  three  opinions  are  very  much  alike,  since  oxygen,  car- 
bon, and  hydrogen,  combined  in  different  proportions,  form  the  mucous 
saccharine  substances  and  the  base  of  the  oxalic  acid.  On  analyzing  the 
animal  substance,  by  means  of  the  nitric  acid,  it  is  reduced  to  this  last 
base,  by  depriving  it  of  a  considerable  quantity  of  azote  which  constitutes 
its  most  remarkable  character. 

But  whence  comes  this  enormous  quantity  of azotef  ?  How  happens  it, 
that  the  flesh  of  a  man  living  exclusively  on  vegetables,  contains  as  much 
azote  and  ammonia,  and  is  as  putrescent,  as  that  of  a  man  Jiving  on  ani- 
mal food  ?  Respiration  does  not  introduce  a  single  particle  of  azote  in  our 
fluids;  this  gas  comes  out  of  the  lungs  as  Unentered  ;  the  oxygen  alone  is 
diminished  in  quantity.  Might  not  one  suspect  that  this  element  of  ani- 
mal substances  is  a  product  of  the  vital  action,  and  that  instead  of  re- 
ceiving it  from  our  aliments;  we  form  it  within  ourselves,  by  an  act  that 
is  hijjicr-chemical;  that  is,  which  chemistry  cannot  imitate  J  ? 

CXI.  It  has  been  maintained,  that  the  hydro-carbonous  oxide,  com- 
"bines,  in  the  stomach  and  intestinal  canal  with  oxygen,  whether  this  last 
principle  has  entered,  with  the  aliments,  into  the  digestive  tube,  or  whe- 
ther it  is  furnished  by  the  decomposition  of  the  fluids  within  that  cavity. 


*  See  the  Jlnnales  tls  CMnue,  a^d  the  Systtme  des  Connaissances  Cfdmiqnes  cle  Four- 
croy.  Tome  X.  page  7'2. 

•j-  The  late  experiments  of  Messrs.  Allen  and  I'cpys  prove,  that  when  an  animal  is 
made  to  breathe  pure  oxygen,  the  blood  disengages  a  certain  quantity  of  azote,  and  ab- 
sorbs an  equal  quantity  of  oxygen.  Philosophical  Transactions,  1809 — Copland. 

\  The  question  asked  by  the  author  is  not  philosophical.  Either  the  elements  of  azote 
must  be  furnished  by  the 'aliment  or  atmosphere,  or  else  the  azote  itself  must  thus  be 
introduced.  Otherwise  we  must  admit  that  the  vital  power  can  create,  azote  without 
materials,  or  from  nothing,  which  is-absurd. — Godmpn. 


The  intestinal  fluids  extricate  azote  which  combines  with  the  alimentary 
mass,  and  occupies  the  place  of  the  carbon  which  the  oxygen  has  taken 
from  it,  to  form  carbonic  acid.  On  reaching  the  lungs,  and  being  again 
exposed  to  the  action  of  the  oxygen  of  the  atmosphere,  this  gas  robs  it 
of  a  portion  of  its  carbon,  and  as  it  disengages  the  azote  of  the  venous 
blood  it  brings  about  a  new  combination  of  that  principle  with  the  chyle. 
Lastly,  propelled  with  the  blood  to  the  surface  of  the  skin,  the  atmos- 
pherical oxygen  disengages  its  carbon,  and  completes  its  azotisation. — 
The  cutaneous  organ  is  perhaps  to  the  lymphatic  system,  what  the  pul- 
monary organ  is  to  the  sanguineous  system. 

The  animalization  of  the  animal  substance  is  therefore  effected,  princi- 
pally by  the  loss  of  its  carbon,  which  is  replaced  by  the  excess  of  azote 
in  the  animal  fluids.  These  maintain  themselves,  in  this  manner,  in  a 
due  temperament ;  for,  continually  parting  with  the  carbonous  principle 
in  the  intestinal,  pulmonary,  and  cutaneous  combinations,  they  would  be 
over  animalized,  if  an  additional  quantity  of  chyle  did  not  seize  the  azote, 
which  is  in  excess.  Still,  this  theory  does  not  account  for  the  formation 
of  the  phosphoric  salts,  of  the  adipocire,  and  a  variety  of  other  products; 
but  without  adopting  it,  to  the  full,  one  may  presume,  from  the  experi- 
ments and  facts  on  which  it  rests,  that  the  oxygen  of  the  atmospherical 
air  is  one  of  the  most  powerful  agents  employed  by  Nature,  in  the  trans- 
formation of  the  aliments  we  live  upon,  into  our  substance. 

How  are  those  animals  nourished  which  live  solely  on  mere  animalized 
flesh,  that  is,  containing  a  greater  quantity  of  azote,  and  a  greater  pro- 
portion of  ammonia  than  their  own  substance.  In  such  a  case,  the  assi- 
milation of  the  aliments,  consist  in  their  disanimalization  either,  by  the 
co-operation  of  all  the  organs,  or  by  the  sole  action  of  the  digestive  or- 
gans, by  the  combination  of  the  gastric  juice  with  the  other  fluids. 

The  constituent  elements  entering  into  the  composition  of  our  organs, 
whether  coming  from  the  exterior,  or  formed  by  the  vital  power  itself, 
are  thrown  out  of  our  body,  by  the  different  emunctories,  and  cease  to 
form  a  part  of  it,  after  remaining  within  it,  for  a  limited  time.  The  urine 
carries  along  with  it,  an  enormous  quantity  of  azote,  the  lungs  and  the 
liver  rid  us  of  the  carbon  and  of  the  hydrogen;  the  oxygen  which  con- 
tains eighty-five  parts  in  the  hundred,  in  the  composition  of  water,  is 
evacuated  by  means  of  the  aqueous  secretions  which  carry  off,  in  a  state 
of  solution,  the  saline  and  other  soluble  principles. 

Among  those  salts  there  is  one,  but  little  soluble,  and  which,  neverthe- 
less, is  of  primary  consequence  among  the  constituent  principles  of  the 
animal  economy.  Phosphate  of  lime,  in  fact,  forms  the  base  of  several 
organs,  it  almost  entirely,  forms  the  osseous  system,  at  an  advanced  pe- 
riod of  life;  all  the  white  organs,  all  our  fluids  contain  a  remarkable 
quantity  of  that  substance,  of  which  the  economy  rids  itself  by  a  kind  of 
dry  secretion.  The  outer  covering  is,  in  all  animals,  the  emunctory  des- 
tined for  that  purpose;  the  annual  moulting  of  birds,  the  fall  of  the  hair 
of  quadrupeds,  the  renovation  of  the  scales  of  fishes  and  reptiles,  carry 
off,  every  year,  a  considerable  quantity  of  calcareous  phosphate.  Man  is 
subject  to  the  same  laws,  with  this  difference,  that  the  annual  desquama- 
tion  of  the  epidermis,  is  not  under  the  absolute  influence  of  the  seasons, 
as  in  the  brute  creation.  The  human  epidermis  is  renewed  annually,  as 
well  as  the  hair  on  the  head  and  on  the  body;  but  this  change  is  brought 
about  gradually,  and  is  not  completed  in  a  season ;  it  does  not  take  place 
in  the  spring,  as  in  most  animals,  nor  in  autumn  with  the  fall  of  the  leaf, 


328 

though  at  these  two  periods,  the  hair  falls  off  in  greatest  quantity,  and 
ihe  desquamation  of  the  cuticle  is  more  active.  These  two  phenomena 
last  throughout  the  whole  year,  as  in  southern  climates,  the  fall  of  the 
leaves  and  the  renovation  of  vegetation  are  continually  going  on.  As  will 
be  mentioned,  in  speaking  of  the  functions  of  generation,  man  living  in 
a  state  of  society,  and  enjoying  all  the  advantages  of  civilization,  is  not 
as  much  under  the  influence  of  the,  seasons  as  the  inferior  animals.  One 
cannot,  however,  but  observe,  that  the  successive  shedding  and  renewing 
of  the  epidermoid  parts,  as  the  cuticle,  the  nails,  and  the  hair,  are  among 
the  most  effective  means  which  nature  possesses  of  parting  with  the  phos- 
phate of  lime,  so  abundant  in  all  animals,  and  which,  nevertheless,  is  so 
insoluble,  and  consequently  so  unfit  to  be  carried  out  of  the  system,  along 
with  the  excrementitious  fluids.  This  effect  is  very  remarkable,  on  the 
termination  of  several  diseases,  in  the  salutary  renovation  of  the  solids 
and  fluids  which  takes  place  during  convalescence.  The  hair  ceases  to 
grow  on  the  bald  head  of  an  old  man;  his  perspiration  diminishes;  may 
not  this  be  the  cause  of  the  great  quantity  of  calcareous  salts,  of  the  os- 
sification of  the  vessels,  of  the  induration  of  the  membranes  ? 

CXII.  What  is  the  ultimate  results  presented  to  us,  by  this  series  of 
functions,  linked  together,  growing  outof*one  another,  and  all  acting  on 
the  matter  of  nutrition,  from  the  moment  it  is  received  within  the  body, 
till  it  is  applied  to  the  growth  and  reparation  of  its  organs*?  It  shows 
us  man  living  within  himself,  nnremittingly  employed  in  converting,  into 
his  own  substance,  heterogeneous  substances,  and  reduced  to  an  existence 
purely  vegetative,  inferior  even  to  the  greater  part  of  organized  beings, 
in  his  powers  of  assimilation.  But  how  high  is  he  not  placed  above  them 
all,  in  the  exercise  of  those  functions  we  are  now  about  to  contemplate, 
functions,  which  raise  him  above  his  own  nature,  which  enlarge  the 
sphere  of  his  existence,  which  serve  him  to  provide  for  all  his  wants,  and 
to  keep  up,  with  all  Nature,  those  manifold  relations  which  subject  her 
to  his  empire  f! 

*  Intimately  connected  with  the  consideration  of  nutrition  is  that  of  reproduction. 
This  phenomena  takes  place  to  a  very -limited  extent,  indeed,  in  the  more  perfect  ani- 
mals ;  but  as  we  descend  in  the  scale  of  creation,  we  find  that  the  destruction  of  a 
member  or  part  of  the  body  of  an  animal  is,  after  a  time,  followed  by  a  partial,  or  entire 
reproduction  of  the  part  destroyed  :  and  amongst  the  lowest  class  of  animals,  even  a 
portion  only  of  the  body  becomes  a  perfect  animal,  and  presents  the  specific  characters 
of  the  parent.  In  this  respect,  the  phenomena  of  .animal  life,  as  we  descend  through  its 
gradations,  approach  those  of  vegetable  existence. — Copland. 

f  For  further  observations  on  Nutrition,  see  APPENDIX,  Notes  S  and  C  C. 


FIRST   CLASS. 


SECOND  ORDER. 

I 


FrxcTioKs  WHICH  TESB  TO  THE  PRESERVATION 

BY  ESTABLISHING  HIS  RELATIONS  WITH  THE  BBISGS 
THAT  STTBHOITSB  HIM. 


231 

CHAPTER  VII. 

OF  SENSATIONS. 


CXIII.  WE  have  already  seen, how  the  human  body,  essentially  change- 
able and  perishable,  maintains  itself  in  its  natural  economy,  carries  on 
its  growth,  and  supplies  its  decay,  by  assimilating  to  its  own  substance, 
principles  that  are  yielded  to  it  by  the  food  it  digests,  and  by  the  air  it 
breathes.  We  shall  now  proceed  to  examine,  by  what  organs  man  is 
enabled  to  keep  up,  with  all  nature,  the  relations  on  which  his  existence 
depends;  by  what  means  he  is  made  aware  of  the  presence  of  objects 
which  concern  him,  what  means  he  possesses  to  fit  his  connexion  with 
them  to  his  welfare,  to  draw  them  towards  him  or  to  repel  them,  to  ap- 
proach or  to  avoid  and  escape  them,  as  he  perceives  in  them  danger,  or 
the  promise  of  enjoyment. 

Man  possesses,  in  all  its  plenitude,  this  new  mode  of  existence,  which 
is  denied  to  vegetable  Nature.  Of  all  the  animals  it  is  he  that  receives 
impressions  the  most  crowded  and  various,  that  is  most  filled  with  sen- 
sations and  that  employs  :hem,  with  the  most  powerful  combination,  as 
the  materials  of  thought,  and  the  sources  of  intelligence :  he  is  the  best 
organized  for  feeling  the  action  of  all  beings  around  him,  and  re-acting 
on  them  in  his  turn.  In  the  study  which  we  are  about  to  undertake,  we 
shall  see  many  instruments  placed  on  the  limits  of  existence,  on  the  sur- 
face of  the  living  being  ready  to  receive  every  impression;  conductors, 
stretching  from  these  in s~.ru ments  to  one  common  centre,  to  which  all  is 
carried;  conductors  through  which  this  central  organ  regulates  the  ac- 
tions, which  now  transport  the  whole  body  from  one  place  to  another 
(locomotion}  ;  now  merely  change  the  relative  situation  of  its  parrs  (fiar- 
tial  motion);  and,  at  othe*  times,  produce,  in  the  organs,  certain  disposi- 
tions, of  which  speech  and  language,  in  their  various  forms,  are  the 
result. 

CXIV.  If  we  are  thoroughly  to  understand  the  mechanism  of  this  ac- 
tion of  outward  objects  on  our  body,  we  must  follow  the  natural  succes- 
sion of  the  phenomena  of  sensation;  studying  first,  the  bodies  which  pro- 
duce the  sensitive  impression,  examining  next,  the  organs  that  receive 
it,  and  next  the  conductors  which  transmit  it  to  a  particular  centre,  whose 
office  is  perception.  To  take  the  sense  of  sight,  for  instance,  we  can 
never  understand  how  it  is  that  light  procures  us  the  knowledge  of  cer- 
tain qualities  of  bodies,  if  we  have  not  learnt  the  laws  to  which  that  fluid 
is  subjected,  if  we  know  nothing  of  the  conformation  of  the  eyes,  of  the 
nerves  by  which  those  organs  communicate  with  the  brain,  and  of  the 
brain  itself,  whither  all  sensations,  or  rather  the  motions  in  which  they 
consist,  are  ultimately  carried. 

CXV.  Of  light.  At  this  day,  the  greater  part  of  Natural  Philosophers 
consider  it  as  a  fluid  impalpable  from  its  exceeding  tenuity.  Many  be- 
lieve it  to  be  only  a  modification  of  caloric,  or  of  the  matter  of  heat ;  and 
this  last  opiniou  has  received  much  plausibility  from  the  late  observa- 


232 

tions  of  Herschel*.  I  shall  not  examine  whether,  as  Descartes  and  his 
followers  imagine,  light,  consisting  of  globular  molecules,  exist  of  itself, 
uniformly  diffused  through  space,  or  as  Newton  has  taught  us  to  believe, 
it  be  but  an  emanation  of  the  sun  and  fixed  stars,  which  throw  off,  from 
their  whole  surface,  a  part  of  their  subsistence,  without  ever  exhausting 
themselves  by  this  continual  efflux  :  It  is  enough  for  us  to  know,  1st,  that 
the  rays  of  this  fluid  move  with  such  velocity,  that  light  passes,  in  a 
second,  through  a  distance  of  seventy-two  thousand  leagues,  since,  ac- 
cording to  the  calculation  of  Roemer  and  the  tables  of  Cassini,  it  traver- 
ses in  something  less  than  eight  minutes,  the  thirty-three  millions  of 
leagues  that  separate  us  from  the  sun;  2dly,  that  light  is  called,  direct, 
when  it  passes  from  the  luminous  body  to  the  eye,  without  meeting  any 
obstacle ;  reflected,  when  it  is  thrown  back  to  that  organ,  by  an  opake 
body;  refracted,  when  its  direction  has  been  changed,  by  passing  from 
one  transparent  medium  to  another  of  different  density;  3dly,  that  the 
rays  of  light  are  reflected  at  an  angle  equal  to  that  of  incidence  ;  that  a 
ray,  passing  through  a  transparent  body,  is  more  strongly  refracted,  as 
the  body  is  more  convex  on  the  surface,  denser,  or  of  more  combustible 
elements.  It  was  from  this  lest  observation,  mat  Newton  conjectured 
the  combustibility  of  the  diamond,  and  the  existence  of  a  combustible 
principle  in  water,  since  placed  beyond  doubt,  by  the  beautiful  experi- 
ments of  modern  chemistry ;  4thiy,  that  a  ray  of  light  refracted  by  a 
glass  prism  is  decomposed  into  seven  rays,  red,  orange,  yellow,  green, 
blue,  indigo,  and  violet.  Each  of  these  rays  is  less  refrangible,  as  it  is 
nearer  to  the  red.  This  ray  is  of  all,  that  which  strikes  the  eye  with  the 
greatest  force,  and  produces  on  the  retina  the  liveliest  impressions.  The 
eagerness  of  savages  for  stuffs  of  this  colour  is  well  known.  Among  al- 
most all  nations  it  has  dyed  the  mantle  of  King?  :  it  is  the  most  brilliant 
and  splendid  of  all  :  there  are  animals  whose  e^es  seem  scarcely  to  sus- 
tain it:  I  have  seen  maniacs  whose  madness,  [after  a  long  suspension, 
never  failed  to  break  out,  at  the  sight  of  a  red  cloth,  or  of  one  cloathed  in 
that  colour.  Green  is,  on  the  contrary,  the  softest  of  colours;  the  most 
permanently  grateful ;  that  which  least  fatigued  the  eyes;  and  on  which 


they  will  longest  and  most  willingly  repose 
been  profuse  of  green,  in  the  colouring  of  all 
some  sort,  of  this  colour,  the  greater  part  of  th 


When  the  eyes  bear  uneasily  the  glare  of  too  i 


.ccordingly,  Nature  has 
lants;  she  has  dyed,  in 
;  surface  of  the  globe. — 


this  colour  are  used  to  soften  the  impression,  which  slightly  tinge,  with 


their  own  hue,  all  the  objects  seen  through  then 
last  in  the  scale,  of  which  the  middle  place  isfi 


trong  a  light,  glasses  of 


Lastly,  the  violet  ray, 
ed  by  the  green,  is  of  all 


the  weakest,  the  most  refrangible.  Of  all  colouts,  violet  has  the  least  lus- 
tre; forms  show  to  less  advantage  under  it;  their  prominences  are  lost; 
painters  accordingly  make  but  little  use  of  it.  "V^hen  an  enlightened  body 


*  This  celebrated  Astronomer  has  published,  in  the  Philosophical  Transactions  of  the 
Royal  Society  for  1800,  a  series  of  experiments,  which  show,  that  the  different  coloured 
rays,  heat,  in  different  degrees,  the  bodies  on  which  they  tall,  and  tJuit  the  red  my, 
which  is  the  least  refrangible,  gives  also  the  greatest  heat. 

The  thermometer  placed  out  of  the  spectrum  and  towards  the  red  ray,  so  that  it 
would  receive  any  rays  yet  less  refrangible,  rises  higher  than  when  it  is  placed  in  that 
colour,  From  waich  Herschel  concludes  that  rays  are  given  out  by  the  sun,  too  little 
refrangible  to  produce  the  sensation  of  light,  and  of  colours,  but  which  produce  the 
Sensation  of  heat — Author's  J\f"otr. 


233 

reflects  all  the  rays,  the  sensations  they  might  separately  produce,  blend 
into  the  sensation  of  white;  if  it  reflects  a  few,  it  appears  differently  co- 
loured, according  to  the  rays  it  repels  ;  finally,  if  all  be  absorbed,  the  sen- 
sation of  black  is  produced,  which  is  merely  the  negation  of  all  colour. 
A  black  body  is  wrapped  in  utter  darkness,  and  is  visible  only  by  the 
lustre  of  those  that  surround  it;  5thly,  that  from  every  point  in  the  sur- 
face of  a  luminous  or  enlightened  body,  there  issue  a  multitude  of  rays, 
diverging  according  to  their  distance,  with  a  proportionate  diminution  of 
their  effect;  so  that  the  rays  from  each  visible  point  of  the  body,  form  a 
cone,  of  which  the  summit  is  at  that  point,  and  the  base,  the  surface  of 
the  eye  on  which  they  fall. 

CXVI.  Sense  of  Sight.  The  eyes,  the  seat  of  this  sense,  are  so  placed,  as 
to  command  a  great  extent  of  objects  at  once,  and  are  enclosed  in  two  os- 
seous cavities,  known  by  the  name  of  orbits.  The  base  of  these  cavities, 
is  forwards,  and  shaped  obliquely  outwards;  so  that  their  outward  side 
not  being  so  ong  as  the  others,  the  ball  of  the  eye  supported,  on  that 
side,  only  by  soft  parts,  may  be  directed  outwards  and  take  cognizance 
of  objects  placed  to  a  side,  without  it  being  necessary,  at  the  same  time, 
to  turn  the  head.  In  proportion  as  we  descend  from  man  in  the  scale  of 
animated  beings,  the  shape  of  the  base  of  the  orbits  becomes  more  and 
more  oblique ;  the  eyes  cease  to  be  directed  forward,  in  short,  the  exter- 
nal side  of  the  socket  disappears,  and  the  sight  is  entirely  directed  out- 
ward, and  as  the  physiognomy  derives  its  principal  character  from  the 
eyes,  its  expression  is  absolutely  changed.  In  certain  animals  very  fleet 
in  running,  such  as  the  hare,  the  lateral  situation  of  the  organs  of  vision, 
prevents  the  animals  from  seeing  small  objects,  placed  directly  before 
them,  hence  those  animals,  when  closely  pursued,  are  so  easily  caught 
in  the  snares  which  are  laid  for  them. 

The  organ  of  sight  consists  of  three  essentially  distinct  parts.  The  one 
set  intended  to  protect  the  eye-ball,  to  screen  it,  at  times,  from  the  influ- 
ence of  light,  and  to  maintain  it  in  the  conditions  necessary  to  the  exer- 
cise of  its  functions  :  these  parts  are  the  eye-brows,  the  eye-lids,  and  the 
lachrymal  apparatus,  and  they  serve  as  appendages  of  the  organ.  The 
eye-ball  itself  contains  two  parts,  answering  very  different  purposes  ;  the 
one,  formed  by  nearly  the  whole  globe,  is  a  real  optical  instrument,  pla- 
ced immediately  in  front  of  the  retina,  and  destined  to  produce  on  the 
luminous  rays  those  changes  which  are  indispensable,  in  the  mechanism 
of  vision  ;  the  other,  formed  by  the  medullary  expansion  of  the  optic 
nerve,  is  the  immediate  organ  of  that  function.  It  is  the  retina,  which 
alone  is  affected  by  the  impression  of  light,  .and  set  in  motion  by  the  con- 
tact of  that  very  subtle  fluid.  This  impression,  this  motion,  this  sensa- 
tion is  transmitted  to  the  cerebral  organ,  by  the  optic  nerve,  the  expan- 
sion of  which  forms  the  retina. 

CXVII.  Of  the  eye-brows,  the  eye-lids,  and  the  lachrymal  apparatus  (Tu- 
tamina  oculi,  Haller.)  The  more  or  less  dark  colour  of  the  hairs  of  the 
eye-brows,  renders  that  projection  very  well  adapted  to  diminish  the  ef- 
fect of  too  vivid  a  light,  by  absorbing  a  part  of  its  rays.  The  eye-brows 
answer  this  purpose,  the  more  completely,  from  being  more  projecting, 
and  from  the  darker  colours  of  the  hairs  which  cover  them  :  hence  we  de- 
press the  eye-brows,  by  knitting  them  transversely,  in  passing  from  the 
dark,  into  a  place  strongly  illuminated*,  which  causes  an  uneasy  sensation 
to  the  organ  of  sight,  Hence,  likewise,  the  custom  that  prevails  with 
some  southern  nations,  whose  eye-brows  are  shaded  by  thicker  and  dark- 

2  G 


234 

er  hairs,  to  blacken  them,  that  they  may  still  better  answer  the  purpose 
for  which  they  are  intended. 

The  eye-lids  are  two  moveable  curtains,  placed  before  the  eyes  which 
they  alternately  cover  and  uncover.  It  was  requisite  that  they  should  be 
on  the  stretch,  and  yet  capable  of  free  motion  ;  now,  both  these  ends  are 
obtained  by  the  tarsal  cartilages,  which  are  situated  along  the  whole  of 
their  free  edges,  and  of  the  muscles  which  enter  into  their  structure*. 
The  cellular  tissue,  which  unites  the  thin  and  delicate  skin  of  the  eye-lids 
to  the  muscular  fibres,  contains,  instead  of  a  consistent  fat,  which  would 
have  impeded  its  motion,  a  gelatinous  lymph,  which,  when  in  excess, 
constitutes  oedema  of  the  eye-lids.  The  tissue  of  the  eye-lids  is  not  abso- 
lutely opaque,  since,  even  when  strongly  drawn  together,  and  completely 
covering  the  globe  of  the  eye,  one  may  still  discern  through  their  texture, 
light  from  darkness.  On  that  account,  light  may  be  considered  as  one  of 
the  causes  of  awakening,  and  it  is  of  consequence  to  keep  in  the  dark, 
patients  fatigued  by  want  of  sleep. 

The  principal  use  of  the  eye-lids  is  to  shade  the  eyes  from  the  continu- 
al impression  of  light.  Like  all  the  organs,  the  eyes  require  to  recruit 
themselves  by  repose;  and  they  had  not  been  able,  to  enjoy  it,  if  the  in- 
cessant impression  of  the  luminous  rays  had  continually  excited  their 
sensibility.  The  removal  of  the  eye-lids  t  is  attended  with  loss  of  sleep. 
The  fluids  are  determined  to  the  affected  organ  which  suffers  from  in- 
cessant irritation.  The  eyes  inflame,  the  inflamation  spreads  towards  the 
brain,  and  the  patient  expires  in  the  most  dreadful  agony.  Thanks  to  an 
advanced  state  of  civilization,  these  barbarous  tortures  have  long  been 
abolished  ;  but  what  happens,  when  from  ectropium  of  one  or  other  of 
the  eye-lids,  a  small  portion  of  the  sclerotic  coat  or  cornea  remains  un- 
covered, proves  the  indispensable  necessity  of  those  parts.  The  spot  ex- 
posed to  the  continued  action  of  the  air  and  of  the  light,  becomes  irritat- 
ed and  inflamed,  and  there  comes  on  an  ophthalmia,  which  can  be  cured 
only,  by  bringing  together,  by  means  of  a  surgical  operation,  the  divided 
edges  of  the  opening  which  is  the  cause  of  the  affection.  From  the  move- 
able  edges  of  both  eye-lids,  there  arise  short  curved  hairs,  of  the  same 
colour  as  those  of  the  eye-brows;  they  are  called  eye-lashes,  and  are  in- 
tended to  prevent  insects,  or  other  very  light  substances,  floating  in  the 
atmosphere,  from  getting  between  the  eye-ball  and  the  eye-lidst. 

The  anterior  part  of  the  eye,  thus  defended  against  external  injuries, 
is  continually  moistened  by  the  tears.  The  organ  which  secretes  this 
fluid,  is  a  small  gland  situate  in  a  depression  at  the  anterior  and  external 
part  of  the  arch  of  the  orbit,  imbedded  in  fat,  and  supplied  with  pretty 
considerable  vessels  and  nerves  in  proportion  to  its  bulk,  and  pouring  the 
fluid  it  secretes,  by  means  of  seven  or  eight  ducts  which  open  on  the 
internal  surface  of  the  upper  eye-lid,  by  capillary  orifices  directed  down- 
ward and  inward.  The  tears  are  a  muco-serous  fluid,  rather  heavier  than 


*  Dr.  Horner  of  Philadelphia,  has  lately  discovered  a  beautiful  muscle  arising  from  the 
os  unguis,  and  inserted  into  the  cartilage  of  the  upper  and  lower  lids,  as  far  as  the  punc- 
ture and  commencement  of  the  lachrymal  duct.     The  office  of  this  muscle  seems  to  be 
that  of  tightening  the  edge  of  the  cartilages  so  as  to  apply  them  closely  to  the  ball  of  the 
eye.     He  has  named  it  Tensor  Tarsi.     See  his  Practical  Anatomy,  p.  116.— Godman. 

f  A  mode  of  punishment  adopted  by  the  ancients,  especially  the  Carthaginians. 

*  They  also  absorb  and  intercept  some  of  the  luminous  rays,  and  thus  diminish  the 
hurtful  effects  of  too  strong  a  light. 


235 

distilled  water,  saltish,  changing  to  a  green  colour,  vegetable  blues,  and 
containing  soda,  muriate,  and  carbonate  of  soda,  and  a  very  small  quan 
tity  of  phosphate  ot  soda  and  of  lime*. 

In  ophthalmia,  the  irritation  of  the  conjunctiva,  transmitted  by  sympa- 
thy, to  the  lachrymal  gland,  not  only  augments  the  quantity  of  its  secre- 
tion, but  appears,  likewise,  to  alter  the  qualities  of  the  fluid  that  is  se- 
creted. The  tears  which,  in  those  cases,  flow  in  such  profusion,  bring 
on  a  sense  of  burning  heat  in  the  inflamed  part;  do  they  not,  perhaps, 
contain  a  greater  quantity  of  the  fixed  alkali  then  in  the  ordinary  state  of 
the  parts,  and  may  not  the  painful  sensation  depend  as  much  on  the  in- 
creased proportion  of  soda  in  the  tears,  as  on  the  greater  sensibility  of 
the  conj  unctiva  ? 

This  last  membrane  is  merely  a  fold  of  the  skin,  which  is  exceedingly 
thin,  covers  the  posterior  surface  of  the  eye-lids,  and  is  then  reflected  over 
the  anterior  surface  of  the  eye,  which  it  thus  unites  to  the  eye-lids.  From 
the  whole  extent  of  this  surface,  there  oozes  an  albuminous  serosity,  which 
mingles  with  tears,  and  adds  to  their  quantity!. 

The  tears  are  equably  difused  over  the  globe  of  the  eye,  by  the  alter- 
nate motions  of  the  palpebrae  ;  they  prevent  the  effects  of  friction,  and 
save  the  organs  of  sight  from  being  dried,  at  that  part  which  is  exposed 
to  the  air.  The  air  dissolves  and  carries  off,  by  evaporation,  a  part  of 
the  lachrymal  fluid.  This  evaporation  of  the  tears  is  proved  by  the  weep- 
ing to  which  those  in  whom  that  secretion  is  very  profuse,  are  subject, 
whenever  the  atmospherical  air,  from  being  damp,  does  not  carry  off  a 
sufficient  quantity  of  the  fluid.  The  unctuous  and  oily  fluid,  secreted  by 
the  meibonian  glands,  smears  the  loose  edge  of  the  palpebrae,  prevents 
the  tears  from  falling  on  the  cheek,  and  answers  the  same  purpose  as  the 
greasy  substances  with  which  one  anoints  the  edges  of  a  vessel,  filled 
above  its  level,  to  prevent  the  overflowing  of  the  contained  fluid. 

The  greatest  part  of  the  tears,  however,  flow  from  without  inward  and 
towards  the  inner  canthus  of  the  eye ;  they  take  that  direction  in  conse- 
quence of  the  natural  slope  of  the  moveable  edge  of  the  palpebrae  of  the 
triangular  groove,  which  is  formed  behind  the  line  of  union  of  the  edges 
whose  round  and  convex  surfaces  touch  each  other  only  in  a  point,  and 
this  course  of  the  tears  is  likewise  promoted  by  the  action  of  the  palpebral 
portions  of  the  orbicularis  palpebrarum,  whose  fibres,  having  their  fixed 
point  at  the  inner  angle  of  the  orbit,  where  the  tendons  is  inserted,  al- 
ways draw  inward  their  external  commissure. 

*  "  The  saline  parts  amount  only  to  about  0  01  of  the  whole.  The  mucus  contained 
in  the  tears  has  the  property  of  absorbing  oxygen  from  the  atmosphere,  and  of  becom- 
ing thick  and  viscid,  and  of  a  yellow  colour.  This  property  of  acquiring  new  properties 
from  the  absorption  of  oxygen  explains  the  changes  which  take  place  in  tears  in  some 
diseases  of  the  eye."  See  the  Chapter,  at  the  end  of  the  APPENDIX,  on  the  Chemical 
Constitution  of  the  Textures  and  Secretions. —  Copland. 

f  There  is  no  opening  in  the  skin  at  the  part  which  corresponds  to  the  globe  of  the 
eye;  it  is  exceedingly  thin,  and  is  continued,  under  the  name  of  the  conjunctiva,  over 
the  transparent  cornea,  to  which  it  adheres  so  firmly,  that  it  is  not  easily  separated  from 
it.  In  some  animals  that  have  no  palpebrx,  the  skin  is  continued,  of  the  same  thickness, 
over  the  tore  part  of  the  eye.  The  conjunctiva  (if,  however,  this  portion  of  skin  de- 
serves that  name)  when  opaque,  renders  the  globe  of  the  eye,  in  other  respects  imper- 
fect, absolutely  useless.  This  is  observed  in  the  kind  of  eel  called  in  books  of  natural 
history,  mnrena  cceciUa:  the  gastrobranchus  ccecus  is  blind  from  the  same  circumstance. 
M.  BIBKS  is  of  opinion  that  it  terminates  at  the  circumference  of  the  cornea 1 


236 

Oft  reaching  the  internal  angle  of  the  palpebrae,  the  tears  accumulate  its 
the  lacus  lachrymalis,  a  small  space  formed  between  the  edges  of  the  pal- 
pebrae,  kept  separated  from  each  other  by  the  caruncula  lachrymalis. 
This  last  substance,  long  considered  by  the  ancients  as  the  secretory  organ 
of  the  tears,  is  merely  a  collection  of  mucous  cryptae  covered  over  by  a 
loose  fold  of  the  conjunctiva.  These  follicles,  alike  in  nature  to  the  mei- 
bomian  glands,  secret  like  them,  an  unctuous  substance  which  smears  the 
rnoveable  edges  of  the  pa'lpebrse,  near  the  internal  commissure.  The 
edges  of  the  eye-lids,  in  this  situation,  require  a  thicker  coating,  as  the 
tears  accumulated  in  that  spot  have  no  where  a  greater  tendency  to  flow 
on  the  cheek. 

Near  the  union  of  the  inner  sixth  of  the  free  edge  of  the  palpebras 
with  the  remaining  five-sixths,  at  the  outer  part,  where  their  internal, 
straight,  or  horizontal  portion  unites  with  the  curved  part,  there  are  situ- 
ated two  small  tubercles,  at  the  top  of  each  of  which  there  is  a  minute 
orifice.  These  are  the  puncta  lachrymalia,  and  they  are  called  superior 
and  inferior,  according  to  the  palpebrse  to  which  they  belong.  In  the 
dead  body,  the  puncta  do  not  appear  to  be  tubercular,  the  small  bulgings 
produced,  doubtless,  by  a  state  of  orgasm  and  of  vital  erection,  collapse  at 
the  approach  of  death.  These  small  apertures,  directed  inward  and  back- 
wards, are  incessantly  immersed  in  the  accumulated  tears,  absorb  them  and 
convey  them  into  the  lachrymal  sac,  by  means  of  the  lachrymal  ducts  of 
which  they  are  the  external  orifices.  The  absorption  of  the  tears,  and 
their  flow  into  a  membranous  reservoir  lodged  in  the  groove  formed  by  the 
os  unguis,  do  not  depend  on  the  capillary  attraction  of  the  lachrymal 
ducts  5  each  of  them,  endowed  with  a  peculiar  vital  action,  takes  up,  by  a 
real  process  of  suction,  the  tears  accumulated  in  the  lacus  lachrymalis, 
and  determines  their  flow  into  the  sac.  The  weight  of  the  fluid,  the 
effort  of  the  columns  which  succeed  each  other,  co-operate  with  the  action 
of  the  parietes  of  the  duct.  The  flow  of  the  tears  is  further  facilitated  by 
the  compression  and  slight  concussions  attending  the  contractions  of  the 
palpebral  fibres  of  the  orbicularis,  behind  which  the  lachrymal  ducts  are 
situated.  This  vitality  of  the  puncta  lachrymalia  and  of  the  ducts  is  rea- 
dily discovered,  when  we  attempt  to  introduce  into  them  Anel's  syringe  or 
Mejean's  stylet,  to  remove  slight  obstructions  of  the  lachrymal  passages, 
In  a  child  now  under  my  care,  fora  mucous  obstruction  of  the  nasal  duct, 
I  can  see  the  puncta  lachrymalia  contract,  when  the  extremity  of  the 
syphon  does  not,  at  once,  enter  the  canal.  One  is  then  obliged  to  wait, 
before  it  can  be  introduced,  for  a  cessation  of  the  spasmodic  contraction, 
sac,  which  lasts  but  a  few  moments.  The  tears  which  which  flow  into 
the  lachrymal  by  the  common  orifice  of  the  united  puncta  lachrymalia, 
never  accumulate  within  it,  except  in  case  of  morbid  obstruction;  they, 
in  that  case,  at  once  enter  into  the  nasal  duct,  which  is  a  continuation  of 
it,  and  fall  into  the  nasal  fossae,  below  the  anterior  part  of  the  inferior 
turbinated  bones  of  these  cavities.  There,  they  unite  with  the  mucous 
of  the  nose,  increase  its  quantity,  render  it  more  fluid,  and  change  its 
composition.  The  use  of  the  tears  is  to  protect  the  eye-ball  against  the 
irritating  impression  of  the  immediate  contact  of  the  atmosphere.  They, 
at  the  same  time,  favour  the  sliding  of  the  palpebrae,  lessen  the  friction 
in  those  parts  and  in  the  eye-ball,  and  thus  promote  their  motion. 

CXVIII.  Of  the  globe  of  the  eye.  The  eye-ball,  as  was  already  ob- 
served, may  be  considered  as  a  dioptrical  instrument  placed  before  the 
retina ;  whose  office  it  is  to  refract  the  luminous  rays,  and  to  collect  them 


237 

into  one  fasciculus,  that  may  strike  a  single  point  of  the  nervous  membrane 
exclusively  calculated  to  ieel  its  impression.  An  outer,  membranous, 
hard,  and  consistent  covering  supports  all  its  parts.  Within  the  first  mem- 
brane called  the  sclerotic,  lies  the  choroid,  adarkish  coat,  which  lines  the 
inside  of  the  sclerotic,  and  forms  the  eye  into  a  real  camera  obscura*. 
At  the  anterior  part  of  the  globe,  there  is  a  circular  opening  in  the  sclerotic 
in  which  the  transparent  cornea  is  inserted.  At  about  the  distance  of  the 
twelfth  part  of  an  inch  from  this  convex  segment,  received  in  the  anterior 
aperture  of  the  sclerotica,  lies  the  iris,  a  membranous  partition  placed 
perpendicularly,  and  containing  a  round  opening,  (the  pupil)  which  di- 
lates or  contracts,  according  to  the  state  of  dilatation  or  contraction  of 
the  iris. 

At  the  distance  of  about  half  a  line  from  the  back  part  of  the  iris,  to- 
wards the  union  of  the  anterior  fourth  of  the  globe  of  the  eye  with  the 
posterior  three  fourths,  opposite  to  the  opening  of  the  pupil,  there  is 
situated  a  lenticular  body,  enclosed  in  a  membranous  capsule,  immo- 
veably  fixed  in  a  situation  by  adhering  to  the  capsule  of  the  vitreous  hu- 
mour. 

Behind  the  crystalline  lens,  the  posterior  three  fourths  of  the  cavity  of 
the  eye  contain  a  viscid  transparent  humour,  enclosed  in  the  cells  of  a 
remarkably  fine  capsule,  called  hyaloid.  This  vitreous  humour  forms 
about  two-thirds  of  a  sphere  from  which  the  anterior  segment  had  been 
taken  out;  the  pulpous  expansion  of  the  optic  nerve,  the  retina,  is  spread 
out  on  its  surface,  so  as  to  be  concentrical  to  the  choroid  and  sclerotic 
coats. 

The  eye-ball  being  nearly  spherical,  the  length  of  its  different  diameters 
differs  but  little.  The  diameter  of  the  eye,  from  the  fore  to  the  back 
part,  is  between  ten  and  eleven  lines  :  the  transverse  and  vertical  diame- 
ters are  somewhat  shorter.  Within  the  space  measured  by  the  diameter 
from  the  fore  to  the  back  part,  there  are  situated,  taking  them  in  their 
order  from  the  fore  part,  the  cornea,  the  aqueous  humour  contained  in 
the  anterior  chamber,  the  iris  and  its  central  opening  or  pupil ;  the  aque- 
ous humour  of  the  posterior  chamber ;  the  crystalline  lens,  surrounded 
by  the  ciliary  processes  ;  then,  the  vitreous  humour  in  its  capsule,  and 
behind  those  transparent  parts  of  the  eye,  through  which  the  luminous 
rays  pass,  in  approaching  to  a  perpendicular,  are  the  retina  which  re- 
ceive the  impression,  the  choroid  whose  black  point  absorbs  the  rays 
that  pass  through  the  thin  and  transparent  retina,  and  the  sclerotic 
in  which  there  is  an  opening  for  the  passage  of  the  optic  nerve  to  the 
globe  of  the  eye. 

The  cornea,  contained  in  the  anterior  aperture  of  the  sclerotica,  like 
the  glass  of  a  watch  case  within  its  frame,  is  about  the  third  of  a  line  in 


*  GMKLIN  (Schweigger's  Journ.  x.  507.)  made  an  interesting1  set  of  experiments,  in 
order  to  determine  the  composition  of  the  black  pigment  which  lines  the  choroid  coat 
of  the  eye. 

"Its  colour,  "he  informs  us,  "  is  blackish  brown,  is  tasteless,  and  adheres  to  the 
tongue  like  clay ;  is  insoluble  in  water,  alcohol,  ether,  oils,  lime-water,  and  distilled 
vinegar.  It  dissolves  in  potash  and  ammonia  when  assisted  by  heat,  and  is  again  preci- 
pitated by  acids.  Sulphuric  acid  dissolves  it,  and  changes  its  colour  to  redish-brown. 
When  distilled,  it  yields  water,  a  brown  oil,  and  carbonate  of  ammonia.  It  gives  out, 
at  the  same  time,  carburetted  hydrogen,  carbonic  oxyde,  azotic  and  oxygen  gasses. 
The  coal  remaining  in  the  retort,  consists  almost  entirely  of  charcoal." — Copland, 


238 

thickness  $  it  forms,  at  the  fore-part  of  the  eye,  the  segment  of  a  smaller 
sphere  :  behind  it  lies  the  aqueous  humour  which  fills  what  are  called  the 
chambers  of  the  eye;  these  form  spaces  divided  into  anterior  and  poste- 
rior, the  former,  which  is  the  larger  of  the  two,  bounded  by  the  cornea 
at  the  forepart,  and  by  the  iris  at  the  back  part;  the  latter,  which  is 
smaller,  and  separates  the  crystalline  humour  from  the  iris,  the  posterior 
part  of  which,  covered  by  a  black  pigment,  is  called  the  uvea*.  The  spe- 
cific gravity  of  the  aqueous  humour  does  not  much  exceed  that  of  dis- 
tilled water;  some  have  even  thought  it  less ;  it  is  albuminous,  and  holds 
in  solution  several  saline  substances!.  The  chrystalline,  enclosed  in  its 
membranous  and  transparent  capsule,  is  a  lenticular  body  rather  solid 
than  fluid  ;  its  consistence  is  particularly  great  to  ward  s4its -centre;  it  there 
forms  a  kind  of  nucleus,  on  which  are  laid  several  concentric  layers, 
whose  density  diminishes  as  they  approach  the  surface,  where  the  ex- 
ternal layers,  truly  fluid,  form  what  Morgagni  considered,  as  a  particu- 
lar liquid  on  which  the  lens  might  be  nourished  by  a  kind  of  imbibition. 
This  body,  composed  of  two  segments  of  unequal  convexity,  about  two 
lines  in  thickness,  as  its  centre,  consists,  of  an  albuminous  substance  coa- 
gulable  by  heat  and  alcohol  $.  Extremely  minute  arteries  given  off  by 
the  central  artery  of  Zinn,  pass  through  the  vitreous  humour,  and  bring 
to  it  the  materials  of  its  growth  and  reparation§. 


*  Some  anatomists  have  doubted  the  existence  of  the  posterior  chamber  of  the  eye  ; 
but  to  be  convinced  of  its  existence,  one  need  but  freeze  an  eye,  when  there  will  be 
found  a  piece  of  ice  between  the  chrystalline  lens  and  the  uvea.  The  formation  of  this 
icicle  is  not  owing  to  the  admission,  through  the  opening  of  the  pupil,  of  the  aqueous 
humour  which,  like  all  other  fluids,  expands  considerably  on  freezing1,  for,  the  expan- 
sion of  fluids  on  their  freezing1,  being  proportioned  to  their  bulk,  the  vitreous  humour 
which  freezes  at  the  same  time  as  the  aqueous,  must  prevent  its  retrogade  flow  through 
the  pupil.  Lastly,  the  uvea  or  posterior  part  of  the  iris  is  covered  with  a  black  point 
which  is  easily  detached  from  it ;  now,  if  the  anterior  part  of  the  chrystalline  lens  had 
been  in  immediate  contact  with  it,  it  would  have  been  soiled  by  some  of  this  colouring 
matter  which  would  have  tarnished  its  natural  transparency,  indispensable  to  perfect 
vision.  It  is,  therefore,  undeniable  that  there  does  exist  a  posterior  chamber,  which  is 
to  the  anterior  in  the  proportion  of  two  to  five,  and  containing-  about  two  fifths  of  the 
aqueous  humour,  the  whole  of  which  is  estimated  at  five  grains,  and  that  the  iris  forms 
a  loose  partition  between  the  two  portions  of  the  aqueous  humour  in  which  the  dai'k 
pigment  of  the  uvea  is  insoluble.  The  aqueous  humour  appears  to  be  the  product  of 
arterial  exhalation ;  it  is  soon  reproduced,  as  we  see  after  the  operation  for  cataract. — 
.Author's  Note. 

•j-  The  Jlqueous  Humour.  Specific  gravity  1.090  at  a  temperature  of  60.  From  various 
recent  experiments,  it  appears  to  be  water  slightly  impregnated  with — 1st.  Albumen  ; 
2d.  Gelatin  ;  3d.  Muriate  of  soda.  Its  constituents,  according-  to  the  analyses  of  Ber- 
zelius,  are : — 

Water 98.10 

Albumen       • a  trace 

Muriates  and  lactates    ....         .         .          1.15 

Soda,  with  animal  matter  soluble  only  in  water      .  75 

100.00 

Copland. 

%  In  the  human  eye  there  are,  strictly  speaking-,  three  lenses.  Two  menisci  and  one 
double  convex,  The  anterior  meniscus  is  formed  by  the  cornea  and  aqueous  humour, 
occupying-  all  the  space  anterior  to  the  double  convex  lens  ;  the  posterior  meniscus  is 
formed  by  the  scleorotica,  &c.  and  the  vitreous  humour,  filling  the  globe  of  the  eye 
posterior  to  the  double  convex  lens,  or  "the  lens"  proper.— Godman. 

§  The  ChrystalUne  Lens.  Its  specific  gravity  is  1.100.  When  fresh  it  has  little  taste. 
It  putrifics  very  rapidly.  It  is  almost  completely  soluble  5n  water.  The  solution  is 


239 

THte  vitreous  humour,  so  called  from  its  resemblance  to  melted  glass, 
is  less  dense  than  the  crystalline,  and  more  so  than  the  vitreous,  and  is  in 
considerable  quantity  in  the  human  eye  ;  it  appears  to  he  secreted  by  the 
minute  arteries  which  are  distributed  to  the  parietes  of  the  membrane  of 
the  vitreous  humour ;  it  is  heavier  than  common  water,  somewhat  albu- 
minous and  saltish*. 

The  sclerotica  is  a  fibrous  membrane  to  which  the  tendons  which  move 
the  globe  of  the  eye  are  attached;  it  supports  all  the  parts  of  that  organ,  and 
these  collapse  and  decay,  whenever  the  continuity  of  its  external  covering 
is  destroyed.  The  use  of  the  choroid,  is  not  so  much  to  avoid  a  covering 
to  the  other  parts,  as  to  present  a  dark  surface,  destined  to  absorb  the 
luminous  rays,  when  they  have  produced  on  the  retina  a  sufficient  im- 
pression. If  it  were  not  for  the  choroid,  the  light  would  be  reflected, 
after  having  impinged  on  the  nervous  membrane,  its  rays  would  cross, 
and  produce  only  indistinct  sensations.  Mariotte  thought  that  the  cho- 
roid was  the  immediate  seat  of  vision,  and  that  the  retina  was  only  its 
epidermisf.  This  hypothesis  would  never  have  obtained  so  much  cele- 
brity, if,  besides  the  objections  that  analogy  might  have  furnished  against 
it,  there  had  been  adduced,  in  opposition  to  it,  the  fact  observed  in  fishes, 
in  which  the  choroid  is  separated  from  the  retina,  by  a  glandular  body, 
opaque  and  incapable  of  transmitting  the  luminous  rays.  The  retina 
loses  its  form,  as  soon  as  it  is  separated  from  the  vitreous  humour,  or 
from  the  choroid  coat,  between  which  it  is  spread  out  as  a  very  thin  cap- 
sule, so  soft  as  to  be  almost  fluid.  A  number  of  blood-vessels,  from  the 
central  artery  of  Zinn,  are  distributed  on  the  nervous  substance  of  the 
retina,  and  give  it  a  slight  pink  colour.  Ought  we,  with  Boerhaave,  to 


partly  coagulated  by  heat,  and  gives  a  copious  precipitate  with  tannin  both  before  and 
after  the  coagulation.  Its  composition,  according  to  the  analyses  of  Berzelius,  is  as 
follows : — 

Water 58.0 

Peculiar  matter    - 35.9 

Muriates,  lactates,  and  animal  matter  soluble  in  ajcohdl        .  2.4 

Animal  matter  soluble  only  in  water  with  some  phosphates  .  1.3 

Portions  of  the  remaining  insoluble  cellular  membrane  .          2.4 

100.0 

The  peculiar  matter  of  the  lens  possesses  all  the  chemical  characters  of  the  colouring 
matter  of  the  blood,  except  colour.  When  burnt  it  leaves  a  little  ash,  containing  a  very 
small  portion  of  iron.  When  its  solution  in  water  is  coagulated  by  boiling,  the  liquid  in. 
which  the  coagulum  was  formed  reddens  litmus,  containing  free  lactic  acid.  [Ann. 
Phil.  11.385.)— Copland 

*  The  Vitreous  Humour  possesses  the  same  properties  as  the  aqttews,  even  its  spec, 
grav.  is  the  same,  or  only  a  very  little  greater.  Its  constituents,  according  to  the  analy- 
sis of  Berzelius,  are  : — 

Water 98.40 

Albumen  0.16 

Muriates  and  lactates      ....         •  1.42 

Soda,  with  animal  matter  soluble  only  in  water      .          0.02 

100.00 

Copland. 

f  Mr.  Jacobs,  of  Dublin,  has  discovered  a  membrane  in  the  eye,  situated  between 
the  choroids  and  retina.  As  no  name  has  yet  been  given  to  it,  we  might  without  im- 
propriety call  it  the  tunica  tenuissima,  as  it  is  the  most  delicate  in  the  human  body. — 
Godman. 


240 

attribute  to  the  aneurismal  or  varicose  enlargements  of  those  smal 
sels,  the  spots  which  are  seen  in  objects,  in  the  disease  to  which  Maitre 
Jean  gave  the  name  of  imaginations  P  In  order  to  form  the  retina,  the 
optic  nerve  which  penetrates  into  the  globe  of  the  eye,  by  piercing  the 
sclerotica,  to  which  the  covering  given  to  that  nerve  by  the  dura  mater 
is  connected;  the  optic  nerve  penetrates  through  a  very  thin  membrane 
perforated  by  a  number  of  small  holes,  and  closing  the  opening  left  by 
the  nerve,  and  which  belongs  as  much  to  the  choroid  as  to  the  sclerotic 
coats;  it  then  spreads  out  to  furnish  the  expansion  which  lines  the  con- 
cavity of  the  choroid,  and  covers  over  the  convex  surface  of  the  vitreous 
humour*.  The  whole  extent  of  the  retina,  which  is  equally  nervous  and 
sentient,  may  receive  the  impressions  of  the  luminous  rays,  though  this 
faculty  has,  by  several  philosophers,  been  exclusively  assigned  to  its  cen- 
tral part,  called  the  optical  axis  or  porus  opticus.  This  central  part  is 
easily  recognized,  in  man,  by  a  yellow  spot  discovered  by  Soemmering: 
in  the  middle  of  this  spot,  situated  at  the.  outer  side  of  the  entrance  of 
the  optic  nerve  into  the  globe  of  the  eye,  there  is  seen  a  dark  spot  and  a 
slight  depression,  the  use  of  which  is  not  understood.  This  peculiar 
structure,  recently  discovered,  is  met  with  only  in  the  eye  of  man  and 
of  monkeys. 

CXIX.  Mechanism  and  phenomena  of  vision.  The  rays  of  light  passing 
from  any  point  of  an  enlightened  object,  form  a  cone  of  which  the  apex 
answers  to  the  point  of  the  object,  and  of  which  the  base  covers  the  an- 
terior part  of  the  cornea.  All  the  rays,  more  diverging,  which  fall 
without  the  area  of  the  cornea  on  thet  eye-brows,  the  eye-lids,  and  the 
sclerotica  are  lost  to  vision.  Those  which  strike  the  mirror  of  the  eye 
pass  through  it,  under  a  refraction  proportioned  to  the  density  of  the 
cornea,  which  much  exceeds  that  of  the  atmosphere,  and  to  the  convexity 
of  that  membrane,  approaching  the  perpendicular,  they  now  pass  through 
the  aqueous  humour,  less  dense,  and  fall  upon  the  membrane  called  the 
iris.  All  those  that  fall  upon  this  membrane  are  reflected,  and  show  its 
colour,  different  in  different  persons,  and  apparently  depending  on  the 
organic  texture,  and  on  the  particular  and  very  diversified  arrangement 
of  the  nerves,  of  the  vessels,  and  cellular  tissue,  which  enter  into  its 
structure.  None  but  the  most  central  traverse  the  pupil  and  serve  to 
sight.  These  will  pass  that  opening,  in  greater  or  less  number,  as  it  is 


*  The  optic  nerves  differ  very  remarkably  from  the  other  cerebral  pairs,  both  in  their 
thickness,  and  in  the  delicacy  of  their  substance,  which  appears  to  be  an  immediate 
continuation  of  medullary  fibres  of  the  brain,  to  which  the  meninges  furnish  one  com- 
mon envelope,  and  not  a  distant  membranous  canal  for  each  fibre. 

The  nerves  of  vision  cross  each  other  before  the  cella  tunica,  in  a  manner  similar  to 
the  primitive  crossing,  which  their  roots,  as  well  as  those  of  the  other  nerves,  undergo 
in  the  substance  of  the  brain.  These  double  decussations  may  be  said  to  neutralize  each 
other,  and  consequently,  each  optic  nerve  may  be  considered  to  arise  primarily  from 
the  hemisphere  corresponding  to  the  eye  which  it  supplies.  In  hemiplegia,  the  affected 
eye  is  not  on  that  side  of  the  body  struck  with  the  paralysis — it  is  on  the  opposite  side 
that  the  pupil  is  dilated,  and  this  pathological  phenomenon,  which  is  easily  proved  in 
persons  who  have  experienced  a  paralytic  seizure,  seems  to  be  one  of  the  best  proofs 
which  can  be  opposed  to  those  who  suppose  that  the  optic  nerves,  where  they  approach 
each  other,  experience  an  approximation  of  their  fibres  only.  It  may  be  farther  argued, 
in  support  of  the  actual  decussation  of  these  nerves,  that  the  wasted  optic  nerve  of  an 
eye  that  has  been  for  some  time  in  a  state  of  atrophy  can  be  traced  towards  the  opposite 
lobe  of  the  brain ;  and  that  an  evident  crossing  of  the  optic  nerve  may  be  observed  m 
many  of  the  classes  of  fishes. —  Copland. 


more  or  less  dilated.  Now,  the  pupil  is  enlarged  or  diminished,  by  the 
contraction  or  expansion  of  the  iris.  The  motions  of  this  membrane 
depend  entirely  on  the  manner  in  which  light  affects  the  retina.  The  iris 
itself  is  insensible  to  the  impressions  of  the  rays  of  light,  as  Fontana  has 
proved,  who  always  found  it  immovable,  when  he  directed  on  it  alone  the 
tlje  luminous  rays.  When  the  retina  is  disagreeably  affected  by  the  lus- 
tre of  too  strong  a  light,  the  pupil  contracts,  to  give  passage  only  to  a 
smaller  number  of  rays:  it  dilates,  on  the  contrary,  in  gloom,  to  admit 
enough  to  make  the  requisite  impression  on  the  retina. 

To  explain  the  motions  of  the  iris,  it  is  not  necessary  to  admit  that 
muscular  fibres  enter  into  its  structure*;  it  is  enough  to  know  its  vascu- 
lar, spongy,  and  nervous  texture;  the  irritation  of  the  retina  sympatheti- 
cally transmitted  to  the  iris,  determines  a  more  copious  afflux  of  humours; 
its  tissue  dilates  and  stretches,  the  circumference  of  the  pupil  is  pushed 
towards  the  axis  of  this  opening,  which  becomes  contracted  by  this  vital 
expansion  of  the  membranous  tissue.  When  the  irritating  cause  ceases 
to  act,  by  our  parsing  from  light  into  darkness,  the  humours  flow  back 
into  the  neighbouring  vessels,  the  membrane  of  the  iris  returns  upon  itself, 
and  the  pupil  enlarges  the  more,  as  the  darkness  is  greater.  ' 

The  rays,  admitted  by  the  pupil,  pass  through  the  aqueous  humour  of 
the  posterior  chamber,  and  soon  meets  the  crystalline,  which  powerfully 
refracts  them,  both  from  its  density  and  its  lenticular  form.  Brought 
towards  the  perpendicular  by  this  body,  they  pass  on  towards  the  retina 


*  Some  anatomists  contend,  and  we  think  justly,  that  two  sets  of  muscular  fibres  enter 
into  the  structure  of  the  iris,  the  one  radiating1,  and  the  other  orbicular.  Amongst  those 
who  have  lately  argued  in  support  of  this  position,  we  may  mention  M  MAU^OIB,  of 
Geneva.  It  appears  to  us,  that  those  who  deny  muscularity  to  this  part,  do  so  in  conse- 
quence of  a  mistaken  idea,  which  seems  to  be  too  generally  adopted,  viz.  that  no  part 
is  really  muscular,  but  that  which  possesses  fibres  of  a  similar  appearance  to  those  which 
perform  the  function  of  voluntary  motion.  It  shouldjrshowever,  be  kept  in  recollection 
that  involuntary  muscles — those  fibrous  textures  who'll  receive  only  nerves  proceeding, 
from  the  ganglia,  which  are  not  supplied  with  voluntary  nerves,  and  which  are,  conse- 
quently, not  directly  influenced  by  the  will — differ  very  essentially  from  voluntary 
muscles  in  their  structure.  Indeed,  muscular  textures  vary  not  only  in  their  functions, 
but  even  in  their  external  characters,  according  as  they  are  more  or  less  plentifully  sup- 
plied with  either  class  of  nerves — the  cerebral  or  ganglial.  The  structure  also  of  mus- 
cular parts,  especially  those  which  are  removed  from  the  influence  of  volition,  has  some 
relation  to  the  kinds  of  irritants  by  which  they  are  designed  by  nature  to  be  influenced. 
Thus,  th-e  eye  being  formed  with  an  intimate  relation  to  the  functions  which  it  has  to 
perform,  and  to  the  external  influences  which  act  on  it,  possesses,  in  the  structure  of 
its  iris,  a  muscular  texture  of  peculiar  delicacy,  and  hence  it  is  more  sensible  to  the 
irritations  which  accompany,  and  are  subservient  to,  the  right  performance  of  this  im- 
portant  animal  function. 

If  the  structure  of  the  iris,  the  number  of  the  soft  and  delicate  nervous  fibrils  wliich 
proceed  to  it  from  the  lenticular  ganglion,  and  the  connexion  which  they  form  with  the 
retina  in  their  course,  be  kept  in  view,  we  shall  readily  be  able  to  comprehend  the 
procession  of  phenomena  which  lead  to  the  motions  of  the  iris.  It  is  not  improbable 
that  the  nervous  fibi-ils  proceeding  from  the  ganglia  to  the  iris,  form,  with  the  capillary 
arteries  wliich  supply  its  cellular  texture,  that  particular  organization  which  may  be 
considered  as  muscular;  or,  in  other  words,  that  these  ganglia!  nerves  terminating 
conjunctly  with  capillary  ramifications  in  the  delicate  cellular  substance  of  the  iris 
constitute,  by  such  a  disposition,  its  particular  structure,  and  enable  it  to  perform  its 
peculiar  functions.  Hence  it  will  be  seen  that  impressions  made  upon  the  retina,  (in  the 
sensible  state  of  that  nervous  expansion,  and  in  proportion  to  the  extent  of  its  sensibility) 
and  transmitted  to  the  iris,  by  means  of  the  connexion  which  exists  between  the  retina 
and  the  nerves  supplying  the  iris,  cause  a  contraction  of  its  circular  fibres:  as  soon  as 
such  impressions  cease,  these  fibres  relax,  and  the  comparative  action,  in  the  circular  and 

2  H 


through  the  vitreous  humour,  less  dense,  and  which  preserves,  without 
increasing  it,  the  refraction  produced  by  the  crystalline  lens.  The  rays, 
gathered  into  one,  strike  on  a  single  point  of  the  retina,  and  produce  the 
impression  which  gives  us  the  idea  of  certain  properties  of  the  body 
which  reflect  them.  As  the  retina  embraces  the  vitreous  humour,  it  pre- 
sents a  very  extensive  surface  to  the  contact  of  the  rays,  which  enables  us 
to  behold,  at  once,  a  great  diversity  of  objects,  variously  situated  towards 
us,  even  when  we  or  these  objects  change  our  relative  situation*.  The 
luminous  rays,  refracted  by  the  transparent  parts  of  the  eye,  form  there- 
fore, in  the  interior  of  the  organ,  a  cone,  of  which  the  base  covers  the 
cornea,  and  applies  to  that  of  the  external  luminous  cone,  whilst  its  apex 
is  on  some  point  of  the  retina.  It  is  conceived,  generally,  that  the  lumi- 
nous cones  issuing  from  all  points  of  the  object  beheld,  cross  in  their 
passage  through  the  eye,  so  that  the  object  is  imaged  on  the  retina  re- 
versed Admitting  this  opinion,  established  on  a  physical  experiment, 
we  have  to  inquire,  why  we  see  objects  upright,  whilst  their  image  is  re- 
versed on  the  retina.  The  best  explanation  we  possess  of  this  phenome- 
na, we  owe  to  the  philosopher  Berkeley,  who  proposed  it  in  his  English 
work,  entitled  Theory  of  Vision,  Sec.  In  his  opinion,  there  is  no  need  of 
the  touch  to  correct  this  error  into  which  sight  ought  to  betray  us.  As 
we  refer  all  our  sensations  to  ourselves,  the  uprightness  of  the  object  is 
only  relative,  and  its  inversion  really  exists  at  the  bottom  of  the  eye. 


radiated  fibres,  giving  rise  to  certain  states  of  pupil,  is  relative  to  the  extent,  to  which 
the  irritation  proceeds  along1  the  axis  of  the  nerves  and  vessels,  and  affects  either  set  of 
fibres. 

According  to  this  view  of  the  Subject,  compression  of  the  brain,  or  an  insensible  state 
of  the  optic  nerve,  is  followed  by  expansion  of  the  pupil,  because  the  first  impression 
requisite  to  contraction  of  the  orbicular  fibres,  cannot  be  made,  unless  occasionally  to  a 


pupil.    The  pup) 

with  worms,  conformably  to  what  is  gciun-iilly  observed  in  the  animal  economy,  namely, 
that  all  orbicular  muscles,  when  no  adjoining1  irritation  exists,  exhibit  a  greater  or  less 
degree  of  relaxation  as  the  vital  energies  are  more  or  less  diminished.  It  would  appear, 
in  a  debilitated  state  of  the  system,  that  the  nervous  influence  proceeding  from  the  len- 
ticular ganglion,  is  insufficient  to  the 'purpose  of  exciting  fully  the  orbicular  fibres  of 
the  iris,  and,  at  the  same  time,  the  retina  perhaps,  possesses  that  low  degree  of  sensi- 
bility to  the  irritation  of  light  which  is  followed  by  an  adequate  effect  upon  the  nerves 
supplying  the  iris.  Indeed,  it  seems,  under  the  circumstances  just  referred  to,  where 
irritation  is  generally  present  in  the  abdominal  viscera,  that  nervous  influence  is  secreted 
in  the  brain  and  parts  adjoining  in  an  insufficient  manner,  and  consequently  the  dimi- 
nished activity  of  the  cerebral  and  ganglial  nerves  supplying  the  various  structures  of 
the  eye  is  the  result.  When,  however,  irritation  exists  in  the  brain,  or  when  an  increase 
of  the  circulation  occurs  in  that  organ,  without  overwhelming-  its  powers,  accompanied 
with,  or  preceded  by,  debility,  the  pupil  contracts,  or  even  remains  contracted,  because, 
in  consequence  of  such  irritation  or  increase  of  circulation  in  the  brain  and  connected 
parts,  the  sensibility  and  nervous  activity  are  heightened. 

*  The  rays  of  light  may  be  said  to  penetrate  or  traverse  the  demi-transparent  tissue 
of  the  retina,  and,  as  it  were,  to  search  through  the  nervous  pulp,  when  they  arrive  at 
the  choroid  coat,  which  is  designed,  in  a  great  measure,  to  absorb  these  rays.  Does  any 
intimate  combination  take  place  between  the  nervous  pulp  and  the  light,  which  may 
give  rise  to  that  sensation  which  follows" a  violent  compression  of  the  globe  of  the  eye 
in  an  obscure  situation?  The  spots  which  are  observable  after  having  had  the  eye 
fixed  for  a  considerable  time,  on  certain  coloured  objects,  do  they  arise  from  this  sort 
of  impregnation  of  the  retina,  or  rather  of  a  portion  of  it,  with  the  rays  of  lighter,  as  is 
more  generally  believed,  has  the  sensibility  of  the  retina  become  partially  increased  Or 
diminished  by  the  circumstance  of  inaction,  or  of  exercise — Copland- 


243 

By  the  point  of  distinct  vision,  is  understood  the  distance  at  which  we 
can  read  a  book  of  which  the  characters  are  of  middling  size,  or  distin- 
guish any  other  object  equally  small.    This  distance  is  not  confined  within 
very  narrow  limits,  since  we  can  read  the  same  book  at  six  inches  from 
the  eye,  or  at  five  or  six  times  the  distance.     This  faculty  of  the  eyes,  to 
adapt  themselves  to  the  distance  and  the  smallness  of  objects,    cannot 
depend,  as  has  been   often  repeated,  on   the  lengthening  or  shortening 
of  the   globe  of  the  eye  by  the  muscles  that  move  it.     Its  four  recti 
muscles  are  not,   in  any  case,  capable  of  compressing  it  on  its  sides, 
nor  of  lengthening  it  by  altering  its  spherical  form;  their  simultaneous 
action  can  only  sink  the  ball  in  its  socket,  flatten  it  from  the  fore  to  the 
back  part,   diminish  its  depth,   and  make  the  refraction,  consequently, 
less  powerful,  when  objects  are  very  distant  or  very  small:  this  last  effect, 
even,  might  be  disputed.    The  eye  which  moves  and  rests  on  the  adipose 
cushion  which  fills  the  bottom  of  the  socket,    is  never  strongly  enough 
pressed  to  lose  its  spherical  figure,  which  of  all  the  forms  in  which  bo- 
dies can  be  invested,  is  that  which,  by  its  especial  nature,  best  resists 
alteration.    The  extremities  of  the  ciliary  processes,  which  surround  the 
circumference  of  the  crystalline  lens,  cannot  act  on  this  transparent  lens, 
compress  nor  move  it:  for,  these  little  membranous  folds,  of  which  the 
aggregate  composes  the  irradiated  disk,  known  under  the  name  of  corpus 
ciliare,  possessing  no  sort  of  contractile  power,  are  incapable  of  moving 
the  crystalline  lens  with  which  their  extremities  lying  in  simple  conti- 
guity have  no  adherence,  and  which,  besides,   is  immovably  fixed  in  the 
depression  which  it  occupies,   by  the  adhesions  of  its  capsule  with  the 
membrane  of  the  vitreous  humour.     The  various  degrees  of  contraction 
or  dilation  of  which  the  eye-ball  is  susceptible,  afford  a  much  more  satis- 
factory explanation  of  this  physiological  problem. 

The  rays  of  light  which  come  from  a  very  near  object,  are  very  diver- 
gent: the  eye  would  want  the  refracting  power  necessary  to  collect  them 
into  one,  if  the  pupil,  contracting  by  the  enlargement  of  the  iris,  did 
not  throw  off  the  more  divergent  rays,  or  those  which  form  the  circum- 
ference of  the  luminous  cone.  Then,  those,  which  form  the  centre  of 
the  cone,  and  which  need  but  a  much  smaller  refraction  for  their  re-union 
on  a  single  point  of  the  retina,  are  alone  admitted  by  the  straightened 
opening.  When,  on  the  contrary,  we  look  at  a  distant  object  from 
which  the  rays  are  given  out,  already  very  convergent,  and  which  need 
but  a  small  refraction  to  bring  them  towards  the  perpendicular,  we  di- 
late the  pupil,  in  order  to  admit  the  more  diverging  rays,  which,  when 
collected,  will  give  the  image  of  the  object.  In  this  respect,  very  small 
bodies  are  on  the  same  footing  as  those  at  a  great  distance. 

Though  the  image  of  every  object  is  traced  at  the  same  time  in  both  our 
eyes,  we  have  but  one  sensation,  because  the  two  sensations  are  in  harmony 
and  are  blended,  and  serve  only,  one  aiding  the  other,  to  make  the  impres- 
sion stronger  and  more  durable.  It  has  long  been  observed,  that  sight  is 
more  precise  and  correct  when  we  use  only  one  eye,  and  Jurine  thinks 
that  the  power  of  the  two  eyes  united  exceeds  only  by  one  thirteenth, 
that  of  a  single  eye.  The  correspondence  of  affectton  requires  the  di- 
rection of  the  optical  axes  on  the  same  objects,  and  be  that  direction 
ever  so  little  disturbed,  we  see  really  double,  which  is  what  happens  in 
squinting. 

If  the  eyes  are  too  powerfully  refractive,  either  by  the  too  great  con- 


244  ^p 

vexity  of  the  cornea  and  the  crystalline,  the  greater  density  of  the  hu- 
mours, or  the  excessive  depth  of  the  ball,  the  rays  of  light,  too  soon  re- 
united, diverge  anew,  fall  scattering  on  the  retina,  and  yield  only  a  con- 
fused sensation.  In  this  defect  of  sight,  called  .myojiia,  the  eye  distin- 
guishes only  very  near  objects,  giving  out  rays  of  such  extreme  diver- 
gence as  to  require  a  very  powerful  refractor.  In  firesbytia^  on  the 'other 
hand  the  cornea  too  much  flattened,  the  crystalline  little  convex,  or  set 
too  deeply,  the  humonrs  too  scanty,  are  the  cause  that  the  rays  are  not 
yet  collected  when  they  fall  upon  the  retina,  so  that  none  but  very  distant 
objects  are  distinctly  seen,  because  the  scarcely  divergent  rays  they^give 
out,  have  no  need  of  much  refraction. 

Myopia  is  sometimes  the  effect  of  the.  habit  which  some  children  get 
of  looking  very  close  at  objects  which  catch  their  attention.  The  pupil 
then  becomes  accustomed  to  great  constriction,  and  dilates  afterwards 
with  difficulty.  It  is  obvious,  that  to  correct  this  vicious  disposition, 
you  must  show  the  child  distant  objects  which  will  strongly  engage  his 
curiosity,  and  keep  him  at  some  distance  from  every  thing  he  looks  at. 

The  sensibility  of  the  retina,  on  some  occasions,  rises  to  such  excess, 
that  the  eye  can  scarcely  bear  the  impression  of  the  faintest  light.  Nyc- 
taclofies,  such  is  the  name  given  to  those  affected  with  this  disorder,  dis- 
tinguish objects  amidst  the  deepest  darkness  5  a  few  rays  are  sufficient 
to  impress  their  organ. 

It  is  related  that  an  English  gentleman,  shut  up  in  a  dark  dungeon, 
came  gradually  to  distinguish  all  it  contained:  when  he  returned  to  the 
light  of  day,  of  which  he  had  in  some  sort  lost  the  habit,  he  could  not 
endure  its  splendour,  the  edges  of  the  pupil,  before  extremely  diluted,  be- 
came contracted  to  such  a  degree  as  entirely  to  efface  the  opening. 

When  on  the  other  hand,  the  retina  has  little  sensibility,  strong  day- 
light is  requisite  to  sight.  This  injury  of  vision,  known  by  the  name  of 
hemeralofiia't,  may  be  considered  as  the  first  step  of  total  paralysis  of  the  4 
oplic  nerve,  or  gutta  serena.  It  may  arise  from  any  thing  that  can  impair 
the  sensibility  of  the  retina.  Saint-Yves  relates,  in  his  work  on  diseases 
of  the  eyes,  many  cases  of  hemeralopia.  The  subjects  were  chiefly  work- 
men, employed  at  the  Hotel  des  Monnoies,  in  melting  the  metals.  The 
inhabitants  of  the  northern  regions,  where  the  earth  is  covered  with  snow 
great  part  of  the  year,  become  at  an  early  age  hemeralopes.  Both  con- 
tract this  weakness,  from  their  eyes  being  habitually  fatigued  by  the 
splendour  of  too  strong  a  light. 

Finally,  in  order  to  the  completion  of  the  mechanism  of  vision,  it  is  re- 
quisite that  all  parts  of  the  eye  be  under  certain  conditions,  the  want  of 
which  is  more  or  less  troublesome.  It  is  especially  necessary,  that  the 
membranes  and  the  humours  which  the  rays  of  light  are  to  pass  through, 
should  be  perfectly  transparent.  Thus  specks  of  the  cornea,  the  closing 
of  the  pupil  by  the  preservation  of  the  membrane  which  stops  that  open- 


*  I  give  to  the  words  nyctalopia  and  hemeralopia  the  same  meaning-  as  all  other  writers 
down  to  Scarpa,  who  has  published  the  latest  Treatise  on  diseases  of  the  eyes.  This 
acceptation  is,  however,  a  grammatical  error,  since  the  two  terms,  nyctalopia,  in  its  Greek 
roots,  signifies  an  affection*  which  takes  away  sight  during-  the  night,  and  hemeralopia 
one  in  which  it  is  lost  during  the  day.  It  is  "accordingly  in  this  sense  that  they  are  used 
by  the  father  of  physic.  I  owe  this  remark  to  Dr.  Houssille  Chamseru,  who  has  care- 
fully verified  the  text  of  Hippocrates  in  the  MS S  of  the  Imperial  Librarv — Author's 
Note. 


245 

ing  during  the  first  months  of  the  life  of  the  foetus;  cataract,  ait  affec- 
tion which  consists  in  the  opacity  of  the  crystalline  lens  or  its  capsule ; 
the  glaucoma,  or  defect  of  transparency  in  the  vitreous  humour,  weak- 
en or  altogether  destroy  sight,  by  impeding  the  passage  of  the  rays  to 
the  retina.  This  membrane  itself  must  be  of  tempered  sensibility  to  be 
suitably  affected  by  their  contact.  The  choroid,  the  concavity  of  which 
it  fills,  must  present  a  coating  black  enough  to  absorb  the  rays  that  pass 
through  it.  It  is  to  the  sensible  decay  of  the  dye  of  the  choroid  in  ad- 
vancing years,  as  much  as  to  the  collapsing  induration,  and  discolouring 
of  different  parts  of  the  eye,  and  the  impaired  sensibility  of  the  retina 
from  long  use,  that  we  ascribe  the  confusion  and  weakness  of  sight  in 
old  people.  The  extreme  delicacy  of  the  eyes  of  the  Minos  pro  vesequally 
the  necessity  of  the  absorption  of  light,  by  the  black  coating  which  cover 
the  choroid. 

The  eyes  are,  of  all  the  organs  of  sense, those  which  are  the  most  deve- 
loped in  a  new-born  child.— They  have  then  nearly  the  bulk  which  they 
j*re  Ur  retain  during  life.  Hence  it  happens,  that  the  countenance  of  chil- 
dren^whose  eyes  are  proportionably  larger,  is  seldom  disagreeable,  be- 
cause it  is  chiefly  in  these  organs  that  physiognomy  seeks  expression. 
Might  we  not  say,  that  if  Nature  sooner  completes  the  organ  of  sight,  it 
is  because  the  changes  which  it  produces  on  the  rays  of  light,  arising 
purely  from  a  physical  necessity,  the  perfection  of  the  instrument  was 
required  for  the  exercise  of  the  sense  ? 

The  eyes  are  not  immoveable  in  the  place  they  occupy.  Drawn  into 
very  various  motions,  by  four  recti  muscles,  and  two  oblique,  they  direct 
themselves  towards  all  objects  of  which  we  wish  to  take  cognizance;  and 
it  is  observed,  that  there  is,  between  the  muscles  which  move  the  two  eyes, 
such,  a  correspondence  of  action,  that  these  organs  turn^at  once  the  same 
way,  and  are  directed,  at  once,  towards  the  same  object,  in  such  a  manner, 
that  the  visual  axes  are  exactly  parallel.  It  sometimes  happens,  that  this 
harmony  of  motion  is  disturbed  ;  and  hence  squinting;  an  affection 
which  depending  almost  always,  on  the  unequal  force  of  the  muscles  of  the 
eye,  may  be  distinguished  into  as  many  species  as  there  are  muscles  which 
can  draw  the  globe  of  the  eye  into  their  direction,  when  from  any  cause, 
they  become  possessed  of  a  predominating  power.  Buffon  has  further  as- 
signed as  a  cause  of  squinting,  the  different  aptitude  of  the  eyes  to  be  affect- 
ed by  light.  According  to  this  celebrated  naturalist,  it  may  happen,  that 
one  of  the  eyes  being  originally  of  greater  sensibility,  the  child  will  close 
the  weaker  to  use  the  stronger,  which  is  yet  strengthened  by  exercise, 
whilst  repose  still  weakens  the  one  which  remains  in  inaction.  The  exami- 
nation of  a  great  many  young  people,  who  had  fullen  under  military  con- 
scription, and  claimed  exemption,  on  the  score  of  infirmities,  has  shown  me 
that  squinting  is  constantly  connected  with  the  unequal  power  of  the  eyes. 
Constantly,  the  inactive  eye  is  the  weakest,  almost  useless,  and  it  was  quite 
a  matter  of  necessity  that  the  diverging  globe  should  be  thus  neutralized, 
else  the  image  it  would  have  sent  to  the  brain,  different  from  that  which  the 
sound  eye  gives,  would  have  introduced  confusion  into  the  vital  functions. 
The  squinting  eye,  being  inactive,  falls  by  degrees  into  that  state  of  debi- 
lity, from  default  of  exercise,  which  Brown  has  so  well  called  indirect  de- 
bility. 

The  sense  of  sight  appears  to  me,  much  rather  to  deserve  the  name  which 
J.  J.  Rousseau  has  given  to  that  of  smell,  of  sense  of  the  imagination. 
Like  that  brilliant  faculty  of  the  soul,  the  sight,  which  furnishes  us  with 


-246 

ideas  so  rich  and  varied,  is  liable  to  betray  us  into  many  errors.  Jt  may 
be  doubted,  whether  it  gives  the  notion  of  distance,  since  the  boy  couch- 
ed by  Cheselden,  conceived  every  thing  he  saw  to  touch  his  eye.  It  ex- 
poses us  to  false  judgments  on  the  form  and  size  of  objects  5  since,  agree- 
ably to  the  laws  of  optics,  a  square  tower  seen  at  a  distance,  appears 
to  us  round  ;  and  very  lofty  trees  seen  also  very  far  off,  seem  no  taller 
than  the  shrubs  near  us.  A  body,  moving  with  great  rapidity,  appears 
to  us  motionless,  Sec.  It  is  from  the  touch,  that  we  gain  the  correction 
of  these  errors,  which  Condillac,  in  his  Treatise  on  Sensation,  has  per- 
haps exaggerated. 

CXX.  The  organ  of  sight,  in  different  animals,  varies  according  to  the 
medium  in  which  they  live;  thus,  in  birds  which  fly  in  the  higher  regions 
of  the  air,  there  is  an  additional  and  very  remarkable  eye-lid:  this  is  par- 
ticularly the  case  with  the  eagle,  which  is  thus  enabled  to  look  at  the  sun, 
and  with  night  birds,  whose  very  delicate  eye  it  seems  to  protect  fromHhe 
effects  of  too  strong  a  light.  In  birds,  likewise,  there  is  a  copious  secre- 
tion of  tears,  the  medium  in  which  they  live  causing  a  considerable  eva- 
poration. The  greater  part  of  fishes,  on  the  contrary,  have  no  jmq^eable 
eye-lid,  and  their  eyes  are  not  moistened  by  tears,  as  the  water  in  which 
they  are  immersed,  answers  the  same  purpose,  In  some  fishes,  however, 
the  eyes  are  smeared  with  an  unctuous  substance  calculated  to  prevent 
the  action  of  the  water  on  the  organ. 

The  globe  of  the  eye  in  birds,  is  remarkable  by  the  convexity  of  the 
cornea,  which  is,  sometimes,  a  complete  hemisphere,  hence  it  possesses 
a  considerable  power  of  refraction.  This  power  of  refraction,  appears  to 
be  very  weak  in  fishes,  the  fore  part  of  their  eyes  being  very  much  flat- 
tened; but  the  water  in  which  they  live  made  it  unnecessary,  that  they 
should  have  an  aqueous  humour,  for,  the  density  of  this  fluid  being  near- 
ly the  same  as  that  of  water,  it  would  not  have  produced  any  refraction  : 
besides,  being,  in  sea-fish,  of  inferior  density  to  that  of  salt-water,  it  would 
have  broken  the  rays  of  light,  by  making  them  diverge  from  the  perpen- 
dicular. In  fact,  the  refractive  power  of  a  medium  is  never  but  a  relative 
quantity ;  the  degree  of  refraction  is  not  determined  by  the  density  of  the 
medium,  but  by  the  difference  of  density  between  it  and  the  medium  that 
is  next  to  it.  To  make  up  for  the  flatness  of  the  cornea  occasioned  by  the 
small  quantity,  or  even  by  the  absence,  of  aqueous  humour,  fishes  have  a 
very  dense  and  spherical  crystalline  humour,  the  spherical  part  of  which 
forms  a  part  of  a  small  sphere. 

The  eyes  of  birds,  whose  cornea  is  thrust  out  by  a  very  copious  aque- 
ous humour,  possess,  in  consequence  of  the  presence  of  this  fluid,  a  very 
considerable  power  of  refraction  ;  the  air,  in  the  higher  regions  of  the  air, 
owing  to  its  extreme  rarefaction,  being  but  little  calculated  to  approxi- 
mate the  rays  of  light. 

The  pupil  admits  of  greater  dilatation  in  the  cat,  in  the  owl,  in  night 
birds,  and  in  general  in  all  animals  that  see  in  the  dark.  The  sensibility 
of  the  retina  appears,  likewise,  greater  in  those  animals  ;  several  of  them 
appear  incommoded  by  the  light  of  day,  aad  never  pursue  their  prey,  but 
in  the  most  obscure  darkness. 

The  crystalline  humour  of  several  aquatic  fowls,  as  the  cormorant's,  is 
spherical  like  that  of  fishes,  and  this  is  not,  as  will  be  mentioned  here- 
after, the  only  peculiarity  of  structure  in  these  kind  of  amphibious  ani- 
mals. Lastly,  the  choroid  of  some  animals,  ifrore  easily  separated  into 
two  distinct  lamina,  than  that  of  man,  presents,  at  the  bottom  of  the  eye, 


'247 

instead  of  a  darkish,  uniformly  diffused  coating,  a  pretty  extensive  spot 
of  various  colours,  and  in  some,  most  beautiful  and  brilliant.  It  is  not 
easy  to  say  what  is  the  use  of  this  coloured  spot,  known  by  the  name  of 
tafietum. 

The  rays  of  light,  reflected  by  this  opaque  substance,  must,  in  passing 
through  the  eye,  cross  those  which  are  entering  at  the  same  time ;  they 
must,  consequently,  prevent  distinct  vision,  or  at  least  impair  the  impres- 
sion, in  a  manner  which  it  is  impossible  to  determine.  It  has  been  said, 
that  the  lower  animals,  provided  with  less  perfect  and  often  less  numerous 
senses  than  those  of  man,  must  have  different  ideas  of  the  universe  ;  is  it 
not,  likewise,  probable,  that  in  consequence  of  the  indistinct  vision  oc- 
casioned by  the  reflection  from  the  tapetum,  they  may  entertain  erroneous 
and  exaggerated  notions  of  the  power  of  man  ?  And.  notwithstanding  the 
power  granted  to  man  by  the  Creator  over  the  lower  animals,  as  we  are 
told  in  the  book  of  Genesis,  is  it  probable  that  those  which  Nature  has 
gifted  with  prodigious  strength,  or  with  offensive  weapons,  would  obey 
the  lord  of  the  creation,  if  they  saw  him  in  his  feeble  and  destitute  con- 
dition, in  a  word,  such  as  he  is  ? 

The  heads  of  insects  with  numerous  eyes,  are  joined  to  their  body,  and 
move  along  with  it  :  their  existence  is,  besides,  so  frail,  that  it  was  re- 
quisite that  Nature  should  furnish  them  abundantly  with  the  means  of 
seeing  those  objects  which  may  be  injurious  to  them.  We  shall  not  en- 
ter, any  farther,  into  these  remarks  relative  to  the  differences  in  the  organ 
of  sight,  in  the  various  kinds  of  animals.  More  ample  details  on  this 
subject  belong,  in  an  especial  manner,  to  Comparative  Anatomy. 

CXXI.  Of  the  Organ  of  Hearing.  Of  Sound.  Sound  is  not,  like  light, 
a  body  having  a  distinct  existence:  we  give  the  name  of  sound  to  a  sen- 
sation which  we  experience,  whenever  the  vibrations  of  an  elastic  body 
strike  our  ears.  All  bodies  are  capable  of  producing  it,  provided  their 
molecules  are  susceptible  of  a  certain  degree  of  re-action  and  resistance. 
When  a  sonorous  body  is  struck,  its  integrant  particles  experience  a  sud- 
den concussion,  are  displaced  and  oscillate  with  more  or  less  rapidity. 
This  tremulous  motion  is  communicated  to  the  bodies  applied  to  its 
surface  ;  if  we  lay  our  hand  on  a  bell  that  has  been  struck  by  its  clapper, 
we  feel  a  certain  degree  of  this  trembling.  The  air,  which  envelopes  the 
sonorous  body,  receives  and  transmits  its  vibrations  with  the  more  effect 
from  being  more  elastic.  Hence,  it  is  observed  that,  caeteris  paribus,  the 
voice  is  heard  at  a  greater  distance  in  winter,  when  the  air  is  dry  and 
condensed  by  the  cold. 

The  sonorous  rays  are  merely  series  of  particles  of  air  along  which  the 
vibration  is  transmitted,  from  the  sonorous  body,  to  the  ear  which  per- 
ceives the  noise  occasioned  by  its  percussion.  These  molecules  partici- 
pate in  the  vibrations  which  are  communicated  to  them ;  they  change 
their  form  and  situation,  in  proportion  as  they  are  nearer  to  the  body  that 
is  struck,  and  vice  versa;  for,  sound  becomes  weaker,  in  proportion  to 
the  increase  of  distance.  But  this  oscillatory  motion  of  the  aerial  mole- 
cules, should  be  well  distinguished  from  that  by  which  the  atmosphere, 
agitated  by  the  winds,  is  transported  and  changes  its  situation.-— 
And  in  the  same  manner  as  the  balance  of  a  pendulum  moves  inces- 
santly within  the  same  limits,  so,  this  oscillatory  motion  affects  the 
molecules  of  the  air  within  the  space  which  they  occupy,  so  that  they 
move  to  and  fro  during  the  presence  or  the  absence  of  the  vibration. 
The  atmospherical  air,  when  set  in  motion,  in  a  considerable  mass  at  a 


248 

time,  produces  no  sound,  unless  in  its  course,  it  meets  with  a  body  which 
vibrates  from  the  percussion  which  it  experiences. 

The  force  of  sound  depends,  entirely  on  the  extent  of  the  vibrations  ex- 
perienced by  the  molecules  of  the  sonorous  body.  In  a  large  bell  struck 
violently,  the  agitation  of  the  molecules  is  such,  that  they  are  transmit- 
ted to  considerable  distances,  and  that  the  form  of  the  body  is  evidently 
changed  by  it.  Acute  or  grave  sounds  are  produced  by  the  greater  or  small- 
er number  of  vibrations,  in  a  given  time,  and  the  vibrations  will  be  more 
numerous,  the  smaller  the  length  and  diameter  of  the  body.  Two  catgut 
strings,  of  the  same  length  and  thickness,  and  with  an  equaldegree  of  ten- 
sion, will  vibrate  an  equal  number  of  times,  in  a  given  time,  and  produce 
the  same  sound.  This,  in  music,  is  called  unison.  If  one  of  the  strings  is 
shortened  by  one  half,  it  vibrates  as  often  again  as  the  other,  and  gives  out 
a  sound  more  acute,  or  higher  by  one  octave.  The  same  result  may  be  ob- 
tained by  reducing  the  string  one  half  of  its  original  thickness,  without 
taking  from  its  length.  The  vibrations  will,  in  the  same  manner,  be 
accelerated,  by  giving  a  greater  degree  of  tension  to  the  sonorous 
cord.  The  difference  of  the  sounds  produced  by  a  bass,  a  harp,  or  any 
other  stringed  instrument,  depends  on  the  unequal  tension,  length,  and 
size  of  the  strings. 

This  division  of  the  elementary  sound  is  an  act  of  the  understanding, 
which  distinguishes,  in  a  noise  apparently  monotonous,  innumerable  va- 
rieties, and  shades  expressed  by  signs  of  convention.  But  in  the  same 
manner  as  light,  refracted  by  a  prism,  presents  innumerable  intermediate 
shades,  between  the  seven  primitive  colours,  and  as  the  transition  is  gra- 
dual, from  the  one  to  the  other  of  these  colours  :  so  the  division  of  the 
primitive  sound  into  seven  tones  expressed  by  notes,  is  not  absolute,  and 
there  are  a  number  of  intermediate  sounds  which  augment  or  diminish 
their  value,  Sec. 

Sound  has,  therefore,  been  analysed  as  well  as  light ;  the  use  of  the  ear, 
with  regard  to  sound,  corresponds  to  that  of  the  prism  with  regard  to 
light,  and  the  modifications  of  which  sound  is  capable,  are  as  numerous 
and  as  various,  as  the  shades  between  the  primitive  colours. 

Sound  is  propagated  with  less  velocity  than  light.  The  report  of  a  can- 
non fired  at  a  distance,  is  heard  only  a  moment  after  the  eye  has  per- 
ceived the  flash  of  the  explosion.  Its  rays  diverge  and  are  reflected,  like 
those  of  light,  when  they  meet  with  an  obstacle  at  an  angle  equal'to  that 
of  incidence.  The  force  of  sound,  like  that  of  light,  may  be  increased 
by  collecting  and  concentrating  its  rays.  The  sonorous  rays  which 
strike  a  hard  and  elastic  body,  when  reflected  by  it,  impart  to  it  a  vibra- 
tory motion,  giving  rise  to  a  secondary  sound,  which  increases  the  force 
of  the  primitive  sound. 

When  these  secondary  sounds,  produced  by  the  percussion  of  a  body 
at  a  certain  distance,  reach  the  ear,  they  give  rise  to  what  is  called  an 
echo.  Who  is  unacquainted  with  the  ingenious  allegory,  by  which  its 
nature  is  expressed  in  ancient  mythology,  in  which  echo  was  called, 
daughter  of  the  air  and  of  the  earth  ? 

CXXII.  Of  the  Organ  and  Mechanism  of  Hearing.  The  organ  of  hear- 
ing in  man,  consists  of  three  very  distinct  parts  ;  the  one  placed  exter- 
nally, is  intonded  to  collect  and  to  transmit  the  sonorous  rays  which  are 
modified  in  passing  along  an  intermediate  cavity,  between  the  external 
and  internal  ear.  It  is  within  the^cavities  of  this  third  part  of  the  organ, 
excavated  in  the  substance  of  the  petrous  portion  of  the  bone,  that  the 


249 

nerve  destined  to  the  perception  of  sound,  exclusively  resides.  The  ex- 
ternal ear  and  the  meatus  auditorily externus  may  be  compared  to  an 
acoustic  trumpet,  the  broad  part  of  which,  represented  by  the  concha, 
collects  the  sonorous  rays  which  are  afterwards  transmitted  along  the 
contracted  part,  represented  by  the  meatus  externus.  The^concha  con- 
tains several  prominences  separated  by  corresponding  depressions ;  its 
concave  part  is  not  wholly  turned  outward,  in  those  who  have  not  laid 
their  ears  flat  against  the  side  of  the  head,  by  tight  bandages,  it  is  turned 
slightly  forward,  and  this  arrangement,  favourable  to  the  collecting  of 
sound,  is  particularly  remarkable  in  savages,  whose  hearing,  it  is  well 
known,  is  remarkably  delicate.  The  base  of  the  concha  consists  of  a  fibro- 
cartilaginous  substance,  thin,  elastic,  calculated  to  reflect  sounds  and  to 
increase  their  strength  and  intensity,  by  the  vibrations  to  which  it  is  lia- 
ble. This  cartilage  is  covered  by  a  very  thin  skin,  under  which  no  fat  is 
collected  that  could  impair  its  elasticity  ;  these  prominences  are  connect- 
ed together  by  small  muscles  :  these  may  relax  it,  by  drawing  the  projec- 
tions together,  and  thus  place  it  in  unison  with  the  acute  or  grave  sounds. 
These  small  muscles  within  the  external  ear,  are  the  musculi  helicis  major 
and  minor;  the  tngicus  and  anti-tragicus  and  the  transversus  auris,  are 
like  the  muscles  on  the  outer  part  of  the  ear,  stronger  and  more  marked 
in  timid  animals  with  long  ears.  In  the  hare,  the  fibres  of  these  muscles 
are  most  distinctly  marked,  their  action  is  most  apparent  in  this  feeble 
and  fearful  animal  which  has  no  resource  but  in  flight,  against  the  dan- 
gers which  incessantly  threaten  his  existence,  and  which  require  that  he 
should  receive  early  intimation  of  the  approach  of  danger;  hence  hares 
have  the  power  of  making  their  ears  assume  various  forms,  of  shaping 
them  into  more  advantageous  trumpets,  of  moving  them  in  every  direc- 
tion, of  directing  them  towards  the  quarter  from  which  the  noise  proceeds, 
so  as  to  meet  the  sounds  and  collect  the  slightest, 

The  form  of  the  external  ear,  is  not  sufficiently  advantageous  in  man, 
whatever  Boerhaave  may  have  said  to  the  contrary,  to  enable  all  the  so- 
rous  rays,  which  in  striking  against  it,  are  reflected  at  an  angle  equal  to 
that  of  their  incidence,  to  be  directed  towards  the  meatus  auditorius  ex- 
ternus. United,  for  the  most  part  into  a  single  fasiculus,  and  directed 
towards  the  concha,  they  penetrate  into  the  meatus  auditorius  externus, 
and  the  tremulous  motions  which  they  excite  in  its  osseo-cartilaginous  pa- 
rietes  contribute  to  increase  their  force.  On  reaching  the  bottom  of  the 
meatus,  they  strike  against  the  membrana  tympani,  a  thin  and  transparent 
septum  stretched  between  the  bottom  of  the  meatus  and  the  cavity  in 
which  the  small  bones  of  the  ear  are  lodged.  These  small  bones  form  a 
chain  of  bone  which  crosses  the  tympanum  from  without  inward,  and 
which  extends  from  the  membrana  tympani  to  that  which  connects  the 
base  of  the  stapes  to  the  edge  of  the  fenestra  ovalis. 

An  elastic  air,  continually  renewed  by  the  Eustachian  tube,  fills  the 
cavity  of  the  tympanum:  small  muscles  attached  to  the  malleus  and 
stapes  move  these  bones  or  relax  the  membranes  to  which  they  are  at- 
tached, and  thus  institute  a  due  relation  between  the  organ  of  hearing  and 
the  sounds  which  strike  it.  It  will  be  easily  conceived,  that  the  relaxa- 
tion of  the  membrana  tympani,  effected  by  the  action  of  the  anterior  mus- 
cle of  the  malleus,  must  weaken  acute  sounds,  while  the  tension  of  the 
same  membrane,  by  the  internal  muscles  of  the  same  bone,  must  increase 
the  force  of  the  grave  sounds.  In  the  same  manner,  as  the  eye  by  the 
contraction  or  dilatation  of  the  pupil,  accommodates  itself  to  the  light, 

2  I 


250 

so  as  to  admit  a  greater  or  smaller  number  of  its  rays,  according  to  the 
impression  which  they  produce,  59  by  the  relaxation  or  tension  of  the 
membrane  of  the  tympanum,  or  of  tlje  fenestra  ovalis,  the  ear  reduces  or 
increases  the  strength  of  sounds  whose  violence  would  affect  its  sensibili- 
ty, in  a  painful  manner,  or  whose  impression  would  be  insufficient.  The 
iris  and  the  muscles  of  the  stapes  and  of  the  malleus  are,  therefore, 
the  regulators  of  the  auditory  and  visual  impression  ;  there  is  as  close  a 
sympathetic  connexion  between  these  muscles  and  the  auditory  nerve, 
as  between  the  iris  and  the  retina*.  The  air  which  fills  the  tympanum 
is  the  true  vehicle  of  sound  ;  this  air  diffuses  itself  over  themastoid  cells, 
the  use  of  which  is  to  augment  the  dimensions  of  the  tympanum,  and  the 
force  and  extent  of  the  vibrations  which  the  air  experiences  within  it. 

These  vibrations  transmitted  by  the  membrana  tympani,  are  commu- 
nicated to  those  membranes  which  cover  the  fenestra  ovalis,  and  the  fe- 
nestra rotunda,  then,  by  means  of  these,  to  the  fluid  which  fills  the  dif- 
ferent cavities  of  the  internal  ear,  and  in  which  lie  the  soft  and  delicate 
filaments  of  the  auditory  nerve  or  of  the  portio  mollis  of  the  seventh 
pair. 

The  agitation  of  the  fluid  affects  these  nerves  and  determines  the  sen- 
sation of  grave  or  acute  sounds,  according  as  they  are  slower  or  more 
rapid.  It  appears  that  the  diversity  of  sounds  should  rather  be  attribu- 
ted to  the  more  or  less  rapid  oscillations,  and  to  the  undulations  of  the 
lymph  of  Cotunni,  than  to  the  impressions  on  filaments  of  different 
lengths,  of  the  auditory  nerve.  These  nervous  filaments  are  too  soft  and 
too  slender  to  be  traced  to  their  extreme  terminations.  It  is,  however, 
probable,  that  the  various  forms  of  the  internal  e ar  (the semi-circular  canals, 
the  "vestibule^  and  the  cochlea^)  have  something  to  do  with  the  diversity  of 
sounds.  It  must  also  be  observed,  th&t  the  cavities  of  the  ear  are  con- 
tained in  a  bony  part,  harder  than  any  other  substance  of  the  same  kind, 
and  well  fitted  to  maintain,  or  even  to  augment  by  the  reaction  of  which 
it  is  capable,  the  force  of  the  sonorous  rays. 

The  essential  part  of  the  organ  of  hearing,  that  which  appears  exclu- 
sively employed  in  receiving  the  sensations  of  sound  is,  doubtless,  that 
which  exists  in  all  animals  endowed  with  the  faculty  of  hearing.  This 
part  is  the  soft  pulp  of  the  auditory  nerve,  floating  in  the  midst  of  a  ge- 
latinous fluid,  contained  in  a  thin  and  elastic  membranous  cavity.  It  is 
found  in  all  animals,  from  man  to  the  sepice.  In  no  animal  lower  in  the 
scale  of  animation,  has  an  organ  of  hearing  been  met  with,  although  some 
of  these  inferior  animals  do  not  seem  to  be  absolutely  destitute  of  that 
organ.  This  gelatinous  pulp  is,  in  the  lobster,  contained  in  a  hard  and  horny 
covering.  In  animals  of  a  higher  order,  its  internal  part  is  divided  into 
various  bony  cavities,  in  birds  there  is  interposed  a  cavity  between  that 
which  contains -the  nerve  of  hearing  and  the  outer  part  of  the  headf,  in 
man  and  in  quadrupeds,  the  organ  of  hearing  is  very  complicated  ;  it  is 
enclosed  in  an  osseous  cavity,  extremely  hard,  situated  at  a  considerable 


*  It  may  be  added,  that  this  connexion  is  formed  very  nearly  in  the  same  way  by 
means  of  the  retrograde  branch  of  the  fi i'th  pair  passing  through  the  internal  ear,  as  the 
supra  orbitar  ID  ranch  through  the  orbit,  to  assist  in  supplying  the  iris. — Guelman. 

•\  In  some  birds,  especially  the  crow,  magpie,  and  raven,  the  semicircular  canals  are 
remarkably  large,  and  cross  each  other  in  a  very  singular  manner,  as  I  have  frequently 
observed.  In  birds  of  the  goose  or  duck  tribe  they  are  small  and  less  peculiar,  whence 
it  may  be  inferred  that  in  birds  the  acuteness  of  hearing  is  very  much  dependent  on  the 
size  of  these  canals. — Gasman. 


.depth,  and  separated  from  the  outer  part  of  the  head,  by  a  cavity  and  a 
canal  along  which  the  sonorous  rays  are  transmitted,  after  having  been 
collected  into  fasciculi  by  trumpets  situated  on  the  outside. 

This  kind  of  natural  analysis  of  the  organ  of  hearing,  is  well  calcula- 
ted to  give  accurate  notions  on  the  -nature  and  importance  of  the  func- 
tions fulfilled  by  each  of  its  parts.  ^But  in  the  investigation  of  the  uses 
and  of  the  relative  importance  of  the  auditory  apparatus,  morbid  anatomy 
furnishes  data  of  an  equal  value  with  those  obtained  from  comparative 
anatomy. 

CXXIII.  The  external  ear  may  be  removed,  with  impunity,  in  man, 
and  even  in  animals  in  which  its  form  is  more  advantageous  ;  the  hearing 
is,  at  first  impaired,  but  at  the  end  of  a  few  days,  recovers  its  wonted  de- 
licacy. The  complete  obliteration  of  the  meatus  auditorius  externus,  is 
attended  with  complete  deafness.  It  is  not  essentially  necessary  for  the 
mechanism  of  hearing1,  that  the  membrana  tympani  should  be  whole  ; 
persons  in  whom  it  has  been  accidentally  ruptured,  can  force  out  smoke 
at  their  ears,  without  losing  the  power  of  hearing;  it  may  be  conceived, 
however,  that  if  instead  of  having  merely  a  small  opening  that  would  not 
prevent  its  receiving  the  impression  of  the  sonorous  rays,  nor  its  being 
acted  upon  by  the  handle  of  the  malleus,  the  membrana  tympani  were  al- 
most entirely  destroyed,  deafness  would  be  the  almost  unavoidable  conse- 
quence*. If,  in  consequence  of  the  obstruction  of  the  Eustachian  tube, 
the  air  in  the  tympanum  is  not  renewed,  it  loses  its  elasticity  and  com- 
bines with  the  mucus  within  the  tympanum.  The  cavity  of  the  tympa- 
num is  then,  in  the  same  condition  as  an  exhausted  receiver,  in  which 
the  sonorous  rays  are  transmitted  with  difficulty.  It  has  been  thought, 
that  the  use  of  the  Eustachian  tube  was,  not  only  to  renew  the  air  con- 
tained in  the  tympanum,  but  also  transmit  the  sonorous  rays  into  that  ca- 
vity. In  listening  attentively,  we  slightly  open  our  mouth  5  in  order,  it  is 
said,  that  the  sound  may  pass  from  this  cavity  into  the  pharynx  and 
thence  reach  the  organ  of  hearing.  This  explanation  is  far  from  satis- 
factory, for  the  obliteration  of  the  meatus  auditorius  externus  is  attended 
with  complete  deafness,  which  would  not  happen,  if  the  Eustachian  tubes 
transmitted  the  sonorous  rays.  When  a  man  listens  attentively,  and 
with  his  mouth  open,  the  condyles  of  the  lower  jaw,  situated  in  front  of 
the  external  auditory  meatus,  being  depressed  and  brought  forward,  the 
openings  are  evidently  enlarged,  as  may  be  ascertained  by  puttiug  the 
the  little  finger  into  one's  ears,  at  the  moment  of  depressing  the  lower 
jawf.  The  luxation  of  the  small  bones  of  the  ear,  or  even  their  complete 
destruction,  does  not  occasion  deafness,  the  only  consequence  is  a  con- 
fusion in  the  perception  of  sounds  When,  however,  the  stapes,  the  base 
of  which  rests  on  the  greatest  part  of  the  fenestra  ovalis,  or  when  the 


*  We  find  that  a  temporary  obstruction  of  the  Eustachian  tube  in  guttural  angina  is 
sufficient  to  occasion  a  considerable  degree  of  deafness.  In  such  a  case,  the  inflamma- 
tion of  the  mucous  membrane  of  the  pharvnx  extends  itself  to  that  which  lines  the  tube, 
of  which  it  is  a  continuation  ;  and  the  effect  that  the  inflammation  produces  on  tne 
function  of  the  organ  are  proportionate  to  the  extent  to  which  it  advances  in  the  differ- 
ent compartments  of  the  internal  ear. —  Copland. 

f  The  open  state  of  the  mouth  in  an  attentive  listener  by  no  means  proves  that  the 
sonorous  rays  are  introduced  along  the  Eustachian  tube.  Indeed,  if  such  were  the  case, 
the  aerial  pulsations  arriving  by  this  direction  would  strike  the  tympanum  in  an  opposite 
direction  to  those  that  are  admitted  by  the  external  passage,  and  thus  render  the  hear- 
ing confused.  The  purpose,  therefore,  which  the  Eustachian  tube  performs  is  nothing 
more  than  to  allow  the  renewal  of  the  air  within  the  tympanum.  —  Copland, 


252 

thin  membrane  which  closes  the  fenestra  ovalis,  or  when  that  which 
closes  the  fenestra  rotunda  is  destroyed,  deafness  takes  place  in  conse- 
quence of  the  escape  of  the  fluid  which  fills  the  cavities  in  which  the  au- 
ditory nerve  is  distributed. 

The  existence  of  this  fluid  appdltafc  essential  to  the  mechanism  of  hear- 
ing, either  from  its  keeping  thenervfte  in  the  soft  and  moist  state  required 
for  the  purpose  of  sensation,  or  from  its  transmitting  to  them,  the  undu- 
latory  motion  with  which  it  is  agitated. 

The  deafness  of  old  people,  which,  according  to  authors,  depends  on 
the  impaired  sensibility  of  the  nerves,  whose  excitability  has  been  ex- 
hausted by  impressions  too  frequently  repeated,  appears  sometimes  to  be 
occasioned  by  a  deficiency  of  this  humour,  and  by  the  want  of  moisture 
in  the  internal  cavities  of  the  ear.  During  the  severe  winter  of  1798, 
Professor  Pinel  opened,  at  the  Hospital  of  Saltpetriere,  the  skulls  of  se- 
veral women  who  died  at  a  very  advanced  age,  and  who  had  been  deaf 
for  several  years.  The  cavities  of  the  internal  ear  were  found  quite  empty; 
they  contained  an  icicle  in  younger  subjects  who  had  possessed  the  power 
of  hearing. 

Deafness  may,  likewise,  be  produced  by  a  palsy  of  the  portio  mollis  of 
the  seventh  pair,  or  by  a  morbid  condition  of  the  part  of  the  brain  from 
which  this  nerve  arises.  The  mechanical  explanation  applied  by  Willis 
to  the  anomalous  affections  of  the  organ  of  hearing,  is  inadmissible,  those 
in  which  that  organ  is  sensible  only  to  the  impression  of  weak  or  strong- 
sounds  acting  together  or  separately. 

This  author  relates  the  case  of  a  woman  who  could  not  hear,  unless  a 
great  noise  was  made  near  her,  either  by  beating  a  drum  or  by  ringing 
a  bell;  because,  says  he,  under  such  circumstances,  these  loud  noises  de- 
termine in  the  membrana  tympani,  which  he  supposes  in  a  state  of  re- 
laxation, the  degree  of  tension  required  to  enable  it  to  vibrate  under  the 
impression  of  weaker  sounds.  This  membrane,  to  prevent  greater  re- 
sistance, must  be  put  on  the  stretch  by  the  internal  muscle  of  the  malleus, 
or  by  its  own  contraction.  The  total  absence  of  muscular  fibres  in  the 
membrana  tympani,  in  man,  renders  very  doubtful  this  spontaneous  con- 
traction. Mr.  Home,  however,  has  just  ascertained  that  the  membrana 
tympani  of  the  elephant  is  muscular  and  contractile.  Admitting  all  these 
suppositions,  we  only  substitute  one  difficulty  for  another,  and  it  remains 
to  be  shown,  why  the  more  powerful  sounds  merely  increase  the  tone  of 
membrana  tympani;  why  they  do  not  become  objects  of  perception  of 
the  organ  of  hearing,  though  they  might  be  expected  to  render  us  insen- 
sible to  the  perception  of  weaker  sounds. 

CXXIV.  Of  odours.  Chemists  have  long  thought  that  the  odoriferous 
part  of  bodies  formed  a  peculiar  principle,  distinct  from  all  the  other 
substances  entering  into  their  composition;  they  gave  it  the  name  of 
aroma;  Fourcroy,  however,  has  clearly  shown,  that  this  pretended  ele- 
ment consisted  merely  of  minute  particles  of  bodies,  detached  by  heat 
and  dissolved  in  the  atmosphere,  which  becomes  loaded  with  them  and 
conveys  them  to  the  olfactory  organs.  According  to  this  theory,  all  bo- 
dies are  odoriferous,  since  caloric  may  sublimate  some  of  the  particles  of 
those  which  are  least  volatile.  Linnaeus  and  Lorry  had  endeavoured  to 
class  odours,  according  to  the  sensations  which  they  produce*;  Four- 

*  L-innzeus  admits  seven  classes  of  odours;  1st  class,  ambrosiac  odours,  those  of  the  rose 
and  cf  musk  belong-  to  this  class,  they  are  characterised  by  their  tenacity ;  2d,  fragrant  ,• 


253 

croy  has  been  guided  by  the  chemical  nature  of  substances;  but  howevef 
advantageous  this  last  classification  may  be,  it  is  difficult  to  include  in  it, 
the  infinite  odours  which  exhale  from  substances  of  all  kinds,  and  it  is 
perhaps  as  difficult  to  arrange  them  in  classes,  as  the  bodies  from  which 
they  are  produced. 

This  being  laid  down  on  the  nature  of  odours,  it  is  next  explained, 
why  the  atmosphere  becomes  loaded  with  the  greater  quantity,  the  warm- 
er and  the  more  moist  it  is.  We  know,  that  in  a  flower-garden,  the  air 
is  at  no  time  more  loaded  with  fragrant  odours,  and  the  smell  is  never 
the  source  of  greater  enjoyment,  than  in  the  morning,  when  the  dew 
is  evaporating  by  the  rays  of  the  sun.  It  is  likewise,  easily  understood, 
why  the  most  pungent  smells  generally  evaporate  very  readily,  as  ether, 
alcohol,  the  spirituous  tinctures,  and  essential  volatile  oils. 

CXXV.  Oftheorgan  of  smell.  The  nasal  fossae,  within  which  this  organ 
is  situated,  are  two  cavities  in  the  depth  of  the  face,  and  extending  back- 
ward into  other  cavities,  called  frontal,  ethmoideal,  sphenoidal,  palatine, 
and  maxillary  sinuses. 

A  pretty  thick  mucous  membrane,  always  moist,  and  in  the  tissue  of 
which,  the  olfactory  nerves  and  a  considerable  number  of  other  nerves 
and  vessels  are  distributed,  lines  the  nostrils  and  extends  into  the  sinuses 
which  communicate  with  them,  and  covers  their  parietes  throughout 
their  windings  and  prominences.  This  membrane,  called  pituitary,  is 
soft  and  fungous,  and  is  the  organ  which  secretes  the  mucus  of  the  nose; 
it  is  thicker  over  the  turbinated  bones  which  lie  within  the  olfactory  ca- 
vities; it  grows  thinner  and  firmer,  in  the  different  sinuses. 

The  smtll  appears  more  delicate  in  proportion  to  the  nasal  fossae  being 
more  capacious,  the  pituitary  membrane  covers  a  greater  space.  The 
soft  and  moist  condition  of  this  membrane  is,  likewise,  essentially  neces- 
sary to  the  perfection  of  this  sense.  In  the  dog,  and  in  all  animals 
which  have  a  very  exquisite  sense  of  smell,  the  frontal,  ethmoideal,  sphe- 
noidal, palatine,  and  maxillary  sinuses,  are  prodigiously  capacious,  and 
the  parietes  of  the  skull  are  in  great  measure  hollowed  by  these  different 
parts  of  the  olfactory  apparatus;  the  turbinated  bones  are,  likewise,  very 
prominent  in  them,  and  the  grooves  between  them  very  deep;  lastly,  the 
nerves  of  the  first  pair  are  large  in  proportion.  Among  the  animals 
possessed  of  great  delicacy  of  smell,  few  are  more  remarkable  than  the 
hog.  This  impure  animal,  accustomed  to  live  in  the  most  offensive 
smells,  and  in  the  most  disgusting  filth,  has,  however,  so  very  nice  a 
smell,  that  it  can  detect  certain  roots,  though  buried  in  the  earth  at  a 
considerable  depth.  In  some  countries,  this  quality  is  turned  to  advan- 
tage, and  swine  are  employed  in  looking  for  trufles.  The  animal  is  taken 
to  those  places  where  they  are  suspected  to  be,  turns  up  the  earth  in 
which  they  are  buried,  and  would  feed  on  them  greedily,  if  the  herdsmen, 
satisfied  with  this  indication,  did  not  drive  them  away  from  this  substance 
intended  for  more  delicate  palates. 

for  example,  the  lily,  the  saffron,  and  jasmine;  they  fly  off  readily  ;  3d,  aromatic,  as  the 
smell  of  the  laurel ;  4th,  aliaceous,  approaching  to  that  of  garlic  ;  5th,  fetid,  as  that  of 
valerian  and  fungi ;  6th,  virous,  as  of  poppies  and  opium ;  7th,  nauseous,  as  that  of 
g-ourds,  me'ons,  cucumbers,  and,  in  general,  all  cucurbitaceous  plants. 

Lorry  admits  orty-  five  kinds  of  odours,  camphorated,  narcotic,  ethereal,  volatile  acid, 
and  alkaline. 

M.  Fourcroy  admits  the  mucous  aroma,  belonging  to  plants,  improperly  termed  inodo- 
rous. Oihj  and  fugacious,  oily  and  volatile,  acid  and  hydro-sulpfiureous.—jlvthor's  Note, 


264 

CXXVI.  Of  the  sensation  of  odours.  Do  the  nerves  of  the  first  pair 
alone  give  to  the  pituitary  membrane,  the  power  of  receiving  the  im- 
pression of  smell,  and  do  the  numerous  filaments  of  the  fifth  pair,  merely 
impart  to  it  the  general  sensibility  belonging  to  other  parts?  This  ques- 
tion appears  to  require  an  answer  in  the  affirmative.  This  pituitary 
membrane,  in  fact,  possesses  two  modes  of  sensibility,  perfectly  distinct, 
since  the  one  of  the  two  may  be  almost  completely  destroyed,  and  the 
other  considerably  increased.  Thus,  in  violent  catarrh,  the  sensibility  of 
the  part,  as  far  as  relates  to  the  touch,  is  very  acute,  since  the  pituitary 
membrane  is  affected  with  pain,  while  the  patient  is  insensible  to  the 
strongest  smells. 

It  seems  probable,  that  the  olfactory  nerves  do  not  extend  into  the 
sinuses,  and  that  these  improve  the  sense  of  smell,  merely  by  retaining, 
for  a  longer  lapse  of  time,  a  considerable  mass  of  air  loaded  with  odori- 
ferous particles.  I  have  known  detergent  injections,  strongly  scented, 
thrown  into  the  antrum  highmorianum  by  a  fistula  in  the  alveolar  pro- 
cesses, produce  no  sensation  of  smell.  A  phial  filled  with  spirituous 
liquor  having  been  applied  to  a  fistula  in  the  frontal  sir. uses,  gave  no  im- 
pression to  the  patient.  The  true  seat  of  the  sense  of  smell  is  at  the  most 
elevated  part  of  the  nostrils,  which  the  nose  covers  over  in  the  form  of  a 
capital.  There  the  pituitary  membrane  is  moister,  receives  into  its  tissue 
the  numerous  filaments  of  the  first  pair  of  nerves,  which  arising  by  two 
roots  from  the  anterior  lobe  of  the  brain,  and  from  the  fissure  which  se- 
parates it  from  the  posterior  lobe,  passes  from  the  cranium  through  the 
openings  of  the  cribriform  plate  of  the  ethmoid  bone,  and  terminates 
forming,  by  the  expansion  of  its  filaments,  a  kind  of  parenchymatous  tis- 
sue not  easily  distinguished  from  that  of  the  membrane.  The  olfactory 
papillae  would  soon  be  destroyed  by  the  contact  of  the  atmospherical  air, 
if  they  were  not  covered  over  by  the  mucus  of  the  nose.  The  use  of  this 
mucus  is,  not  merely  to  preserve  the  extremities  of  the  nerves  in  a  sen- 
tient state,  by  preventing  them  from  becoming  dry,  but,  likewise,  to 
lessen  the  too  strong  impression  that  would  arise  from  the  immediate 
contact  of  the  odoriferous  particles.  It  perhaps  even  combines  with  the 
odours,  and  these  affect  the  olfactory  organs,  only  when  dissolved  in  mu- 
cus, as  the  food  in  saliva. 

As  the  air  is  the  vehicle  of  odours,  these  affect  the  pituitary  membrane, 
only  when  we  inhale  it  into  the  nostrils.  Hence,  when  any  odour  is 
grateful  to  us,  we  take  in  short  and  frequent  inspirations,  that  the  whole 
of  the  air,  which  is  received  into  the  lungs,  may  pass  through  the  nasal 
fossse.  We,  on  the  contrary,  breathe  through  the  mouth,  or  we  suspend 
respiration  altogether,  when  smells  are  disagreeable  to  us. 

The  sense  of  smell,  like  all  the  other  senses,  is  readily  impressed  in 
children;  though  the  nasal  fossae  are,  in  them,  much  contracted,  and 
though  the  sinuses  are  not  yet  formed.  The  general  increase  of  sensi- 
bility, at  this  period  of  life,  makes  up  for  the  imperfect  state  of  the  or- 
ganization; and  it  is,  in  this  respect,  with  the  nasal  fossae,  as  with  the 
auditory  apparatus,  of  which  an  important  part,  the  meatus  exturnus,  is 
then  not  completely  evolved.  The  sense  of  smell  is  perfected  by  the  loss 
of  some  of  the  other  senses;  every  body,  for  example,  knows  the  history 
of  the  blind  man  whom  that  organ  enabled  to  judge  of  the  continence  of 
his  daughter:  it  becomes  blunted  by  the  application  of  strong  and  pun- 
gent odours.  Thus,  snuff  changes  the  quality  of  the  mucus  secreted  by 


255 

the  membrane  of  the  nose,  alters  its  tissue,  dries  its  nerves,  and,  in  the 
course  of  time,  impairs  their  sensibility. 

The  shortness  of  the  distance  between  the  origin  of  the  olfactory 
nerves,  in  the  brain,  and  their  termination  in  the  nasal  fossae,  render 
very  prompt  and  easy  the  transmission  of  the  impressions  which  they 
experience.  This  vicinity  to  the  brain,  induces  us  to  apply  to  those 
nerves,  stimulants  calculated  to  rouse  the  sensibility,  when  life  is  sus- 
pended, as  in  fainting  and  asphyxia.  The  sympathetic  connexions,  be- 
tween the  pituitary  membrane  and  the  diaphragm,  account  for  the  good 
effects  of  sternutatories,  in  cases  of  apparent  death. 

CXXVII.  Of  flavours.  Flavours  are  no  less  varied  and  no  less  nume- 
rous than  odours;  and  it  is  as  difficult  to  reduce  them  to  general  classes 
connected  by  analogies  and  including  the  whole*.  Besides,  there  exists 
no  element  of  flavour,  any  more  than  an  odoriferous  principle.  The 
flavour  of  fruits  alters  as  they  ripen,  and  appears  to  depend  on  the 
inward  composition  of  bodies,  on  their  peculiar  nature,  rather  than  on 
the  form  of  their  molecules,  since  crystals  of  the  same  figure,  but  belong- 
ing to  different  salts,  do  not  produce  similar  sensations. 

To  affect  the  organ  of  taste,  a  body  should  be  soluble  at  the  ordinary 
temperature  of  the  saliva;  all  insoluble  substances  are  insipid,  and  one 
might  apply  to  the  organ  of  taste,  this  celebrated  axiom  in  chemistry, 
corpora  non  agunt  nisi  soluta.  If  there  is  a  complete  absence  of  saliva, 
and  if  the  body  that  is  chewed  is  altogether  without  moisture,  it  will 
affect  the  parched  tongue,  only  by  its  tactile,  and  not  at  all  by  its  gusta- 
tory qualities.  The  substances  which  have  most  flavour,  are  those  which 
yield  most  readily  to  chemical  combinations  and  decompositions,  as  acids, 
alkalies,  and  neutral  salts.  When,  in  affections  of  the  digestive  organs, 
the  tongue  is  covered  with  a  mucous  or  whitish  fur,  or  of  yellowish  or 
bilious  colour,  we  have  only  incorrect  ideas  of  flavours;  the  thinner  or 
thicker  coating  prevents  the  immediate  contact  of  the  sapid  particles; 
when  they  act,  besides,  on  the  nervous  papillae,  the  impression  which 
they  produce  is  lost  in  that  occasioned  by  the  morbid  contents  of  the 
stomach:  hence  every  aliment  appears  bitter,  while  the  bilious  disposi- 
tion exists,  and  insipid,  in  those  diseases  in  which  the  mucous  elements 
prevail. 

CXXVIII.  Of  tlie  sense  of  taste.  No  sense  is  so  much  akin  to  lhat  of 
the  touch,  or  resembles  it  more.  The  surface  of  the  organ  of  taste  differs 
from  the  common  integuments,  only  in  this  respect,  that  the  chorion,  the 
mucous  body,  and  the  epidermis  which  envelope  the  fleshy  part  of  the 
tongue  are  softer,  thinner,  and  receive  a  greater  quantity  of  nerves  and 
vessels,  and  are  habitually  moistened  by  the  saliva  and  by  the  mucus,  se- 
creted by  the  mucous  glands  contaitied'in  their  substances.  These  mu- 
cous cryptas,  and  the  nerves  of  the  cutaneous  covering  of  the  tongue,  raise 
the  very  thin  epidermis  which  covers  its  upper  surface,  and  form  a  num- 


*  This  has  been  attempted,  though  with  indifferent  success,  by  Boerhaave,  Haller, 
and  Linnaus.  Acid,  s-weet,  bitter,  acrid,  saltish,  alkaline,  vinous,  spirituous,  aromatic,  and 
acerb,  were  the  terms  employed  by  those  physicians,  to  express  the  general  characters 
of  flavours. 

The  flavour  of  any  substance  appears  chiefly  to  arise  from  the  odoriferous  particles 
which  escape  from  it,  during  the  process  of  mastication  and  deglutition,  through  the 
posterior  nares,  and  aftect  the  olfactory  nerves  in  that  situation.— Authors  Note, 


her  of  papillae  distinguished,  by  their  form,  into  fungous,  conical^  and  vtt* 
lous.  With  the  exception  of  the  first  kind,  these  small  prominences  are 
formed  by  the  extremities  of  nerves,  surrounded  by  blood-vessels,  which 
give  to  these  papillae  the  power  of  becoming  turgid  and  prominent,  and 
of  being  affected  with  a  kind  of  erection  when  we  eat  highly  seasoned 
food,  or  when  we  long  for  a  savoury  dish.  The  fungous  papillae  are 
mostly  situated  at  the  remotest  part  of  the  upper  surface  of  the  tongue, 
towards  its  root,  and  where  it  forms  a  part  of  the  isthmus  faucium. 
The  pressure  with  which  they  are  affected  by  the  alimentary  bolus,  in  its 
passage  from  the  mouth  into  the  pharynx,  squeezes  out  the  mucus  which 
lubricates  the  edges  of  the  aperture,  and  serves  to  promote  its  passage: 
these  mucous  follicles,  fulfil,  in  this  respect,  the  same  office  as  the 
amygdalae. 

The  upper  surface  of  the  tongue  is  the  seat  of  taste:  it  is  undeniable, 
however,  that  the  lips,  the  gums,  the  membrane  lining  the  arch  of  the 
palate,  and  the  velum  palati*,  may  be  affected  by  the  impression  of  cer- 
tain flavours. 

It  is  observed,  in  the  different  animals,  that  the  organ  of  taste  is  more 
perfect,  according  as  the  nerves  of  the  tongue  are  larger,  its  skin  thinner 
and  moister,  its  tissue  more  flexible,,  its  surface  more  extensive,  its  mo- 
tions easier  and  more  varied.  Hence,  the  bone  in  the  tongue  of  birds, 
by  diminishing  its  flexibility,  the  osseous  scales  of  the  swan's  tongue,  by 
reducing  the  extent  of  the  sentient  surface;  the  adhesion  of  the  tongue  to 
the  jaws,  in  frogs,  in  the  salamander,  and  in  the  crocodile,  by  preventing 
freedom  of  motion,  render  in  these  animals  the  sense  of  taste  duller  and 
less  calculated  to  feel  the  impressions  of  sapid  bodies,  than  in  man,  and 
the  other  mammiferous  animals.  Man  would,  probably,  excel  all  the 
other  animals,  in  delicacy  of  taste,  if  he  did  not,  at  an  early  period,  im- 
pair its  sensibility,  by  strong  drinks,  and  by  the  use  of  spices,  and  of  all 
the  luxuries  that  are  daily  brought  to  our  tables.  The  quadruped  whose 
tongue  is  covered  by  a  rougher  skin,  discover  better  than  we  can,  by  the 
sense  of  taste,  poisonous,  or  noxious  substances.  We  know,  that  in  the 
variety  of  plants  which  cover  the  face  of  the  earth,  herbivorous  animals 
select  a  certain  number  of  plants  suited  to  their  nature,  and  uniformly 
reject  those  which  would  be  injurious  to  them. 

CXXIX.  Is  the  lingual  branch  of  the  fifth  pair  of  nerves,  alone  sub- 
servient to  the  sense  of  taste  ?  Are  not  the  ninth  pair  (almost  wholly  dis- 
tributed in  the  tissue  of  the  tongue,)  and  the  glosso  pharyngeal  branch  of 
the  eighth,  likewise  subservient  to  this  function  ?  Most  anatomists,  since 
Galen,  have  thought  that  the  eighth  and  ninth  pair  supplied  the  tongue 
"with  its  nerves  of  motion,  and  that  it  received  from  the  fifth,  its  nerves  of 
sensation.  Several  filaments,  however,  of  the  great  hypoglossal  nerve,  may 
be  traced  into  the  nervous  papillae  of  the  tongue.  This  nerve  is  larger  than 
the  lingual,  and  is  more  exclusively  distributed  to  this  organ  than  the 
fifth  pair,  to  which  the  other  nerve  belongs.  Havermann  states  that  he 
knew  a  case,  in  which  the  sense  of  taste  was  lost  from  the  division  of  the 
nerve  of  the  ninth  pair,  in  removing  a  schirrous  gland.  This  case,  how- 

*  Especially  the  anterior  part  of  the  palatine  membrane.  The  naso-palatine  nerve, 
discovered  by  Scarpa,  after  arising  from  the  ganglion  of  Meckel,  and  going  for  a 
considerable  distance  into  the  nasal  fossx,  terminates  in  that  thick  and  rugous  portion 
of  the  palatine  membrane,  situated  behind  the  upper  incisors,  and  with  winch  the  tip 
of  the  tongue  is  in  such  frequent  contact.— .-farter'*  J\foif. 


ever,  appears  to  me  a  very  suspicious  one.  The  patient  might  still  have 
tasted,  by  means  of  the  lingual  nerve,  and  the  sense  would  only  have  been 
weakened.  The  division  of  one  of  the  nerves  of  the  ninth  pair  could 
render  insensible,  only  that  half  of  the  tongue  to  which  it  is  distributed, 
the  other  half  would  continue  fully  to  possess  the  faculty  of  taste. 

The  application  of  metals  to  the  different  nervous  filaments  distributed 
to  the  tongue,  ought,  to  inform  us  of  their  different  uses,  if,  as  Humboldt 
suspects,  the  galvanic  excitement  of  the  nerves  of  motion,  alone  produces 
contractions.  To  ascertain  the  truth  of  this  conjecture,  I  placed  a  plate 
of  zinc  within  the  skull,  under  the  trunk  of  the  nerve  of  the  fifth  pair,  in 
a  dog  that  had  been  killed  a  few  minutes  before,  and  that  still  retained  its 
warmth  5  the  muscles  of  the  tongue,  under  which  a  piece  of  silver  was 
placed,  quivered  very  slightly;  those  of  the  forehead  and  temples  in  con- 
tact with  the  same  metal  experienced  very  sensible  contractions,  when- 
ever a  communication  was  made  by  means  of  an  iron  rod.  This  experi- 
ment showed,  that  the  lingual  branch  of  this  nerve  was,  almost  solely, 
subservent  to  the  sensation  of  taste,  which  agrees  with  the  opinion  of 
most  physiologists,  and  the  same  inference  may  be  drawn  from  the  ana- 
tomical knowledge  of  the  situation  of  this  nerve,  which,  almost  entire- 
ly, terminates  in  the  papilla  of  the  membrane  of  the  tongue,  and  sends 
very  few  filaments  to  the  muscles  of  that  organ.  But  though  the  galvanic 
irritation  applied  to  the  hypoglossal  nerve  affected  the  whole  tongue,  in 
a  convulsive  manner,  I  did  not  think  myself  justified  to  infer,  that  this 
nerve  was  solely  destined  to  perform  its  motions;  as  this  nervous  trunk 
might  in  this  part  of  the  body,  as  it  does  in  others,  contain  filaments  both 
of  sensation  and  motion. 

The  tongue  though  an  azygous  organ  is  formed  of  parts  completely 
symmetrical;  there  are,  on  each  side,  four  muscles  (stylo,  hyo,  genio- 
giossi,  and  lingual;}  three  nerves  (lingual,  glosso-pharyngeal,  and  hyfioglossal;) 
a  ranine  artery  and  vein;  and  a  set  of  lymphatic  vessels  precisely  alike. 
All  these  parts,  by  their  union,  form  a  fleshy  body  of  a  close  texture,  and 
not  easily  unravelled,  similar  to  that  of  the  ventricles  of  the  heart,  endowed 
with  a  considerable  degree  of  mobility,  in  consequence  of  the  numerous 
vessels  and  nerves  entering  into  its  substance*.  If  we  compare  their  num- 
ber and  size  with  the  small  bulk  of  the  organ,  it  will  be  readily  under- 
stood, that,  as  no  part  of  the  bode  can  execute  more  frequent,  more  ex- 
tensive, and  more  varied  motions,  so  no  one  receives  more  vessels  and 
nerves.  A  middle  line  separates  and  marks  the  limits  of  the  two  halves 
of  the  tongue,  which  anatomically  and  physiologically  considered,  ap- 
pear formed  of  two  distinct  organs  in  juxta-position. 

This  independence  of  the  two  parts  of  the  tongue  is  confirmed  by  the 
phenomena  of  disease;  in  hemiplegia,  the  side  of  the  tongue  correspond- 


*  HAILER  concluded  that  the  tongue  possesses  irritability.  BLUMEXBACH  has  lately 
determined  the  point  by  direct  experiment.  He  caused  the  tongue  of  a  four-year-old 
ox,  which  had  been  killed  in  the  usual  way,  to  be  cutout  while  the  animal  was  jet  warm, 
and  at  the  same  time,  the  heart,  in  order  that  he  might  compare  the  oscillatory  motions 
of  both  viscera;  and  when  both  were  excited  at  the  same  time  by  mechanical  stimuli, 
the  tongue  appeared  to  survive  the  heart  by  more  than  seven  minutes,  and  so  vivid  were 
its  movements,  when  cut  across  after  its  separation,  that  its  motions  might  be  compared 
to  those  of  the  tail  of  a  mutilated  snake.  The  same  phenomena  were  remarkable  in  the 
divided  tongue  of  other  animals,  on  the  application  of  mechanical  or  chemical  stimuli ; 
and  also  in  that  of  a  boy  which  had  been  bit  oft'  during1  a  fit  of  violent  epilepsy — Cop- 
land. 

2  K 


ing  to  the  half  of  the  body  that  is  paralyzed,  loses,  likewise,  the  power 
of  motion;  the  other  retains  its  mobility,  and  draws  the  tongue  towards 
that  side.  In  carcinoma  of  the  tongue,  one  side  remains  unaffected  by 
the  affection  which  destroys  the  other  half;  lastly,  the  arteries  and  nerves 
of  the  left  side  rarely  anastomose  with  those  on  the  right ;  injections 
forced  along  one  of  the  ranine  arteries,  fill  only  the  corresponding  half 
of  the  organ,  Sec. 

CXXX.  Of  tfo  touch.  No  part  of  the  surface  of  our  body  is  exposed 
to  receive  the  touch  of  a  foreign  body,  without  our  being  speedily  in- 
formed of  it.  If  the  organs  of  sight,  of  hearing,  of  smell,  and  of  taste, 
occupied  only  limited  spaces,  touch  resides  in  all  the  other  parts,  and  ef- 
fectually watches  over  our  preservation.  The  touch  distributed  over  the 
whole  surface,  appears  to  be  the  elementary  sense,  and  all  the  others  are 
only  modifications  of  it,  accommodated  to  certain  properties  of  bodies. 
All  that  is  not  light,  sound,  smell,  or  flavour,  is  appreciated  by  the  touch, 
which  thus  instructs  us  in  the  greater  part  of  the  qualities  of  bodies 
which  it  concerns  us  to  know,  as  their  temperature,  their  consistence, 
their  state  of  dryness  or  humidity,  their  figure,  their  size,  their  distance, 
Sec.  It  corrects  the  errors  of  the  sight  and  of  all  the  other  senses,  of 
which  it  may  justly  be  called  the  regulator,  and  it  furnishes  us  with  the 
most  exact  and  distinct  ideas. 

The  touch  of  which  some  authors  have  sought  to  consecrate  the  excel- 
lence, by  giving  it  the  name  of  the  geometrical  sense,  is  not,  however, 
safe  from  all  mistake.  Whilst  it  is  employed  on  the  geometrical  pro- 
perties, derived  from  space,  and  that  it  appreciates  the  length,  the  breadth, 
the  thickness  the  form  of  bodies,  it  transmits  to  the  intellect,  rigorous 
and  mathematical  results  ;  but  the  ideas  we  acquire,  by  its  means,  on.  the 
temperature  of  bodies,  are  far  from  being  equally  precise.  For,  if  you 
have  just  touched  ice,  another  body  colder  than  yours,  will  appear  warm. 
It  is  for  this  reason,  that  subterraneous  places  appear  warm  to  us  during 
winter.  They  have  kept  their  temperature  whilst  all  things  else  have 
changed  theirs  ;  and  as  we  judge  of  the  heat  of  an  object  by  its  relation 
not  only  to  our  own,  but  also  to  that  of  other  bodies  and  of  the  air  about 
us,  we  find  the  same  places  warm  which  has  appeared  cold  to  us,  in  the 
middle  of  summer. 

The  densest  bodies  being  the  best  conductors  of  heat*,  marble,  metals, 
8cc.  appear  colder  to  us  than  they  really  are,  because  they  carry  it  off  so 
rapidly.  Marble  and  metals,  when  polished,  appear  still  colder,  because, 
as  they  touch  the  skin  in  many  more  points  at  once,  they  affect  this  ab- 
straction more  effectually.  Every  one  knows  the  experiment  of  placing 
a  little  ball  between  the  two  fingers  crossed,  and  producing  the  sensation 
of  two  different  balls. 

CXXXI.  Of  the  integuments.     The  general  covering  of  the  whole  body 


*  Woolly  substances,  &c.  all  felts,  of  which  the  crossing  hairs  confine,  in  some  sort, 
a  great  quantity  of  air,  a  fluid  which  from  its  gaseous  state,  is  a  very  bad  conductor  of 
heat,  retain  heat  well -.—and,  of  equal  thickness,  a  stuff  of  tine  wool,  of  which  the  hairs 
are  more  separated,  the  tissue  softer,  will  be  warmer  than  a  stuff  of  coarse  wool,  of 
which  the  threads,  too  close,  form  a  dense  body,  through  which  cold  as  well  as  heat, 
will  pass  with  ease.  It  is  by  thus  confining  a  certain  mass  of  air,  that  snow  keeps  the 
soil  it  covers,  in  a  mild  temperature,  and  preserves  plants  from  the  injury  of  excessive 
cold;  a  physical  truth  which  is  found  figuratively  expressed,  in  the  words  of  the  Psalm- 
ist, «  Et  dcdit  ilti  nivemjkanquam  vestimentiim.— Gutter's  JVbte. 


259 

is  the  organ  of  touch,  which  resides  in  the  skin  properly  so  called.  The 
cellular  tissue  which  connects  together  all  our  parts,  forms  over  the  whole 
body,  a  layer  varying  in  thickness,  which  covers  it,  in  every  part;  it  is 
called  fianniculus  adijwsus.  As  it  approaches  the  surface,  its  lamina  are 
more  condensed,  are  in  more  immediate  contact  with  each  other,  and 
are  no  longer  separated  by  adeps.  It  is  by  the  closer  juxta-posidon  of 
the  lamina  of  the  cellular  tissue,  that  the  skin  or  dermis  is  formed,  a 
dense  and  elastic  membrane,  into  which  numerous  vessels,  of  all  kinds, 
are  distributed,  and  into  which  so  great  a  quantity  of  nerves  terminate, 
that  the  ancients  did  not  hesitate  to  consider  the  skin  as  purely  nervous. 

In  certain  parts  of  the  body,  a  very  thin  muscular  plane  separates  the 
skin  from  the  panniculus  adiposus.  This  kind  of  panniculus  carnosus 
envelopes,  almost  entirely,  the  body  of  some  animals  ;  its  contractions 
wrinkle  their  skin  covered  with  hairs,  these  rise,  vibrate,  and  thus  are 
cleared  of  the  dust  and  dirt  which  may  have  gathered  on  them.  It  is  by 
means  of  a  cutaneous  muscle?  of  very  complex  structure,  that  the  hedge- 
hog is  enabled  to  coil  himself  up,  and  to  present  to  his  enemy  a  surface 
studded  with  sharp  points :  only  a  few  scattered  rudiments  of  an  analo- 
gous structure,  are  to  be  met  with  in  the  human  body  ;  the  occipito  fron- 
talis,  the  corrugator  supercilii,  several  muscles  of  the  face,  the  platysma 
moides,  the  palmaris  cutaneous  may  be  considered  as  forming  part  of 
this  muscle*.  We  may  even  include  the  cremaster,  whose  expanded  fi- 
bres, surrounded  by  the  dartos,  have  misled  some  anatomists  to  such  a 
degree,  that  they  have  admitted  the  existence  of  a  muscular  texture  in 
the  latter.  These  fibres  of  the  cremaster,  produce  distinct  motions,  in 
the  skin  of  the  scrotum,  wrinkle  it,  in  a  transverse  direction,  and,  at  the 
same  time,  bring  up  the  testicles.  The  platysma  myoides  acts,  likewise, 
on  the  skin  of  the  neck  ;  lastly,  the  occipito-frontalis,  in  some  men,  per- 
forms so  distinct  a  motion  of  the  hairy  scalp,  as  to  throw  off  a  hat,  a  cap, 
or  any  other  covering  that  may  be  on  the  head.  One  may  compare  to  the 
panniculus  carnosus,  the  muscular  coat  of  the  digestive  tube  situated, 
throughout  its  whole  length,  below  the  mucous  membrane,  which  is 
merely  a  prolongation  of  the  skin  modified  and  softened. 

But  if,  in  man,  the  subcutaneous  muscle,  from  its  imperfect  state,  an- 
swers purposes  only  of  secondary  importance,  the  layer  of  cellular  adi- 
pose substance,  extended  under  the  skin,  gives  to  the  latter  its  tension,  its 
whiteness,  its  polish,  it?  suppleness,  favours  its  applying  itself  to  tangi- 
ble objects,  and  thus  renders  the  touch ^nore  delicate.  Too  hard  or  too 
wrinkled  a  skin,  would  have  applied  itself  in  a  very  incomplete  manner, 
to  bodies  of  a  small  size,  and  would  not  readily  have  accommodated  itself 
to  the  small  irregularities  of  those  of  inconsiderable  bulk.  Hence  the 
pulp  of  the  fingers,  which  is  the  seat  of  a  more  delicate  touch,  is  furnish- 
ed with  a  kind  of  adipose  cushion  supported  by  the  nails,  ready  to  be  ap- 

*  In  the  human  body,  the  only  muscle  which  bears  any  resemblance  to  the  pannicu- 
lus carnosus  of  animals  is  the  platysma  myoides,  a  muscle  of  the  face,  arising1  below  the 
clavicles  terminating  at  the  angle  of  the  mouth  and  sometimes  reaching  to  the  zy- 
goma. As  to  the  occipto-frontalis,  also  a  muscle  of  the  face,  and  the  comigutor  super- 
cilii lying  under  it,  (not  to  speak  of  the  palmaris  longus,  having  a  strong  fleshy  belly, 
with  a  distinct  tendon,  inserted  into  the  palmar  aponeurosis,)  we  must  say,  that  our  au, 
thor  has  made  an  unnecessary  and  fruitless  effort  to  find  a  resemblance,  which  really  does 
not  exist  The  cvemaster  is  separated  from  the  integuments  of  the  scrotum,  by  a  dense 
process  of  the  superficial  fascia,  and  therefore  CAKTKOT  produce  the  transverse  corruga- 
tion of  the  scrotum.— Godman. 


260 

plied  to  polished  surfaces,  and  to  discover  the  slightest  asperites*  I  have 
observed  the  sense  of  touch  to  be  very  imperfect,  in  men  wasted  by  ma- 
rasmus, and  whose  hard,  dry,  and  wrinkled  skin  adheres,  in  certain  si- 
tuations, to  the  subjacent  parts. 

The  chemical  analysis  of  the  cutaneous  tissue  shows,  that  it  does  not 
exactly  resemble  that  of  the  cellular  and  membranous  tissue  ;  it  is  gela- 
tino-fibrous,  and,  with  regard  to  its  structure  and  to  its  share  of  contrac- 
tility, it  occupies  a  medium,  between  the  cellular  tissues  and  the  muscular 
flesh*.  There  arise,  from  the  surface  of  ihe  skin,  innumerable  small 
papillae,  fungous,  conical,  pointed,  obtuse  and  variously  shaped,  in  the 
different  parts  of  the  body.  These  papillae  are  merely  the  pulpous  extre- 
mities of  the  nerves  which  terminate  into  them,  and  around  which  there 
are  distributed  vascular  tissues  of  the  utmost  minuteness.  The  papillae 
of  the  skin,  which  are  more  distinct  in  the  fingers  and  lips  than  else- 
where, swell,  v/hen  irritated,  elevate,  in  a  manner,  the  epidermis,  and 
this  kind  of  erection,  which  is  useful  when  we  wish  to  touch  a  substance 
with  great  precision,  may  be  excited  by  friction  or  by  moderate  heat. 

The  nervous  or  sentient  surface  of  the  skin  is  covered  with  a  mucous 
coating,  colourless  in  Europeans,  of  dark  colour,  from  the  effects  of  light, 
among  the  natives  of  southern  climates  5  of  a  gelatinous  nature,  destined 
to  maintain  the  papillse  in  that  state  of  moisture  and  softness  favourable 
to  the  toucfc.  This  mucilaginous  layer,  known  under  the  name  of  ret-e 
mucosu?n  of  Malpighi,  seem  to  contain  the  principle  which  causes  the  va- 
riety of  colour  in  the  skin  of  different  nations,  as  will  be  observed,  in 
speaking  of  the  varieties  of  the  human  species. 

The  reticular  state  of  the  rete  mucosum  may  be  explained  in  two  ways; 
a  thin  and  gelatinous  layer,  extending  on  the  papillar  surface  of  the  skin, 
is  perforated,  at  each  nervous  papilla;  and  if  it  were  possible  to  coagulate 
or  to  detach  this  coating,  we  should  have  a  real  sieve,  or  reticulated  mesh 
work,  _with  a  perforation  at  every  point,  corresponding  to  a  cutaneous  pa- 
pillse. The  sanguineous  and  lymphatic  capillaries,  which  surround  the 
nervous  papillse,  form,  besides,  by  their  connexions,  a  net-work,  the 
meshes  of  which  are  very  minute  and  adhere  to  the  epidermis,  by  a  mul- 
titude of  small  vascular  filaments  that  insinuate  themselves  between  the 
scales  of  this  last  envelopef. 

The  skin  would  be  unable  to  perform  its  functions,  if  an  outer,  thin, 
and  transparent  membrane,  the  ejiidcrmis^  did  not  prevent  it  from  being 
over  dried.  This  superficial  co^ring  is  quite  insensible,  no  nerves  and 
no  vessels,  of  any  kind,  are  found  in  it,  and  even  in  the  present  state  of 
science,  we  do  not  understand  how  it  is  formed,  how  it  repairs  and  repro- 
duces itself  when  destroyed.  The  most  minute  researches  on  its  struc- 
ture, merely  show  the  existence  of  an  infinite  number  of  lamellae,  lying 
over  each  other,  and  overlapping  each  other,  like  the  tiles  of  a  roof.  This 
imbrication  of  the  epidermoid  lamellae,  is  very  obvious  in  fishes  and  rep- 


*  See  the  Chapter  in  the  APPENDIX,  on  the  chemical  constitution  of  the  animal  tex- 
tures and  secretions. —  Copland. 

| And  terminate  in  exhaling  or  absorbing-  pores,  according  as  they  belong- 
to  the  arterial  capillaries,  or  Jto  the  lymphatic  absorbents.  It  is  sufficient,  indeed,  to 
remove  gently  the  scales  of  the  epidermis,  in  order  to  bear  their  orifices  and  procure 
the  absorption  of  any  virus.  It  is  the  net-work  of  MALPIGHI,  or  rather  this  assemblage 
of  interlaced  capillary  vessels  below  the  epidermis,  which  appears  to  be  the  seat  of  the 
primary  phenomena  iji  the  majority  of  cutaneous  inflammations  and  eruptive  diseases.— r_ 
Copland. 


tiles,  the  scaly  skin  of  which  is  merely  an  epidermis  whose  parts  are 
much  more  coarsely  shaped. 

It  was  observed  (XLII.)  in  the  account  of  absorption,  how  much  fric- 
tion facilitates  the  absorption  of  substances  applied  to  the  surface  of  the 
skin,  by  raising  the  scales  of  the  epidermis,  so  as  to  expose  the  orifices  of 
the  absorbents,  whose  activity,  it  in  other  respects,  increases. 

Haller  conceives,  that  the  epidermis  is  formed  by  the  drying  up  of  the 
outer  layers  of  the  rete  mucosum.  Morgagni  thinks  it  is  formed  by  the 
induration  of  the  skin  in  consequence  of  the  pressure  of  the  atmosphere. 
In  objection  to  these  hypotheses,  one  may  inquire,  how  it  happens,  that 
by  the  time  the  foetus,  immersed  in  the  liquor  amnii,  has  attained  its 
third  month,  it  is  covered  with  such  an  envelope.  Pressure  renders  the 
skin  hard  and  callous,  increases  considerably  its  thickness,  as  we  see  in 
the  soles  of  the  feet  and  in  the  palms  of  the  hands  of  persons  engaged  in 
laborious  employments.  The  epidermis  reproduces  itself  with  an  incre- 
dible rapidity,  after  falling  off  in  scales,  after  erysipelas  or  herpetic  erup- 
tions, or,  when  removed,  in  large  flakes,  by  blistering,  it  is  renewed  in 
the  course  of  a  very  few  days.  The  cuticle,  together  with  the  hairs  and 
the  nails,  which  may  be  considered  as  productions  of  the  same  substance, 
are  the  only  parts,  in  man,  that  are  capable  of  reproducing  themselves. 
The  hairs  and  the  horns  of  quadrupeds,  the  feathers  of  birds,  the  calca- 
reous matter  of  the  lobster  and  of  several  mollusca,  the  shell  of  the  turtle, 
the  solid  sheaths  of  a  number  of  insects,  possess,  as  well  as  the  epidermis, 
this  singular  property.  In  other  respects,  the  chemical  structure  of  all 
these  parts  is  the  same ;  they  all  contain  a  considerable  portion  of  phos- 
phate of  lime,  withstand  decomposition,  and  give  out  a  considerable  quan- 
tity of  ammonia,  on  being  exposed  to  heat.  The  use  of  the  epidermis  is 
to  cover  the  nervous  papilla?,  in  which  the  faculty  of  the  touch  essentially 
resides,  to  moderate  the  too  vivid  impression  that  would  have  been  pro- 
duced by  an  immediate  contact,  and  to  prevent  the  air  from  drying  the 
skin,  or  from  impairing  its  sensibility. 

The  dessication  of  the  cutaneous  tissue  is  further  prevented,  and  its 
suppleness  maintained,  by  an  oily  substance,  which  exudes  through  its 
pores,  and  is  apparently  secreted  by  the  cutaneous  exhalants.  This  unc- 
tuous liniment  should  not  be  mistaken  for  that  which  is  furnished  by  the 
sebaceous  glands,  in  certain  situations,  as  around  the  nostrils,  in  the  hol- 
low of  the  arm-pits,  and  in  the  groins.  This  adipose  substance,  with 
which  the  skin  is  anointed,  is  abundant  and  fetid  in  some  persons,  especi- 
ally in  those  of  a  bilious  temperament,  with  red  hair.  It  is,  likewise,  more 
copious  in  the  African  negroes,  as  if  Nature  had  been  anxious  to  guard 
against  the  too  rapid  dessication,  by  the  burning  atmosphere  of  tropical 
climates.  This  use  of  the  oil  of  the  skin,  is,  likewise,  answered  by  the 
tallow,  the  fat,  and  the  disgusting  substances  with  which  the  Canresancl 
the  Hottentots  anoint  their  body,  in  the  manner  described  under  the  name 
of  tattooing,  by  the  travellers*  who  have  penetrated  into  the  interior  of 
the  burning  regions  of  Africa. 

The  ancients  had  a  somewhat  similar  practice,  and  the  anointing  with 
oil,  so  frequently  used  in  ancient  Rome,  answered  the  same  purpose,  of 


*  Among1  others  Kolben,  Description  dn  Cap  de  Bon?ie-Es/)erance.    Sparmann,  Voyage 
au  Cap  de  Bonne  F^perance  et  Chez  fes  Hottentots.     Vaillant,  Voyage  dens  PInterieur  de 


262 

softening  the  skin,  of  preventing  its  becoming  dry,  or  chapped*.  The 
pomatums  employed  at  the  present  day  at  the  toilet,  possess  the  same  ad- 
vantages. The  continual  transudation  of  this  animal  oil  renders  it  ne- 
cessary, occasionally,  to  clean  the  skin  by  bathing;  the  water  removes 
the  dust  and  the  other  impurities  which  may  be  attached  to  its  surface 
by  the  fluid  which  lucubrates  it.  It  is  this  humour  which  soils  our  linen, 
and  obliges  us  so  frequently  to  renew  that  in  immediate  contact  with  the 
skin,  and  which  makes  the  water  collect  in  drops  when  we  come  out  of 
the  bath,  See. 

Though  the  parts  in  which  there  is  found  the  greatest  quantity  of  sub- 
cutaneous fat,  are  not  always  the  most  oily,  and  though  one  cannot  con- 
sider this  secretion  as  a  mere  filtration  of  this  adeps  through  the  tissue  of 
the  skin,  corpulence  has,  however,  a  manifest  influence  on  its  quantity.  I 
know  several  very  corpulent  persons  in  whom  it  appears  to  be  evacuated 
by  perspiration,  on  their  being  heated  by.  the  slightest  exertion.  They  all 
grease  their  linen  in  less  than  twenty-four  hours.  An  excess  of  the  oily 
matter  of  perspiration  is  injurious,  by  preventing  the  evacuation  of  the 
perspiration  and  its  solution  in  the  atmosphere. 

We  all  know,  how,  after  the  epidermis  has  been  removed,  the  slightest 
contact  is  painful:  that  of  the  air  is  sufficient  to  bring  on  a  painful  in- 
flammation of  the  skin  exposed  by  the  application  of  a  blister.  The  epi- 
dermis, as  was  likewise  mentioned  in  speaking  of  the  absorption,  placed 
on  the  limits  of  the  animal  economy,  and  in  a  manner  inorganic,  serves 
to  prevent  heterogeneous  substances  from  being  too  readily  admitted  into 
the  body,  and,  at  the  same  time,  it  lessens  the  too  vivid  action  of  external 
objects  on  our  organs.  All  organized  and  living  bodies  are  furnished 
with  this  covering,  and,  in  all,  in  the  seed  of  a  plant,  in  its  stem  and  on 
the  surface  of  the  body,  in  man  and  animals,  it  bears  to  the  skin  the  great- 
est analogy  of  function  and  nature.  Incorruptibility  is,  in  a  manner,  its 
essence,  and  is  its  peculiar  character;  and  in  tombs  which  contain  mere- 
ly the  dust  of  the  skeleton,  it  is  not  uncommon  to  find  the  whole,  and  in 
a  state  to  be  readily  distinguished,  the  thickened  epidermis  that  forms  the 
soal  of  the  foot,. and  especially  the  heel.  However,  this  incorruptibility 
is  possessed,  as  well  as  others  of  the  qualities  of  the  skin,  by  the  hairs  and 
the  nails,  which  may  be  considered  as  its  appendages. 

CXXXII.  Of  the  Nails.  The  nails  are,  in  fact,  only  a  part  of  the  epi- 
dermis :  they  are  continuous  with  it,  and,  after  death,  fall  off  along  with 
it.  They  are  thicker  and  harder  ;  like  it  they  are  inorganic  and  lamel- 
lated;  they  grow  rapidly  from  the  root  towards  their  free  extremity; 
they  reproduce  themselves  rapidly,  and  acquire  several  inches  in  length, 
when  the  part  beyond  the  ends  of  the  fingers  and  toes  has  not  been  re- 
moved; as  is  the  case  with  the  Indian  fakirs.  In-this  state  of  develope- 
ment,  they  bend  over  the  tips  of  the  fingers  and  toes,  and  impair  the  sense 
of  touch,  whose  free  enjoyment  is  preferable  to  any  advantages  which 
savages  can  derive  from  their  long  and  crooked  nails,  in  defending  them- 
selves, or  in  attacking  animals,  or  tearing  to  pieces  those  which  they  have 
killed  in  hunting.  The  nails  are  quite  insensible,  and  the  reason  that  so 
much  pain  is  felt  when  ths  nails  run  into  the  flesh,  and  that  the  operation 
of  tearing  them  out,  which  is  sometimes  necessary,  is  so  painful,  is,  that 

*  The  reply  of  the  old  soldier  is  well  known,  who,  on  being  asked  by  Augustus,  how 
he  came  to  live  so  long,  said  he  owed  his  long  life  to  the  use  of  \vine  inwardly,  and  to 
that  of  oil  outwardly ;  intus  rino,  extusoleo. — .Author's  Note. 


the  nerves,  over  which  the  nail  grows,  are  more  or  less  injured  when  it 
grows  in  a  wrong  direction.  The  pain  from  the  growing  of  the  nails  into 
the  quick,  is  no  proof  of  their  being  sentient,  any  more  than  the  growth  of 
corns  proves  the.  sensibility  of  the  epidermis,  of  which  they  are  but  thick- 
ened parts,  become  hard  and  callous  by  pressure,  and  which,  confined  in 
tight  shoes,  press  painfully  on  the  nerves  below.  The  nail  itself  may  ac- 
quire a  considerable  degree  of  thickness;  I  have  seen  that  of  a  great  toe 
nearly  half  an  inch  thick.  The  use  of  the  nails  is  to  support  the  tips  of 
the  fingers,  when  they  are  applied  to  unyielding  substances  5  they  like- 
wise concur  in  improving  the  mechanism  of  the  touch*. 

CXXXIII.  Of  the  hair  on  the  head  and  on  other  fiarts  of  the  body. 
These  parts  are  treated  of,  in  the  present  instance,  only  in  consequence 
of  their  connexion  with  the  epidermis ;  as,  far  from  improving  the  touch, 
they  interfere  with  it,  or  at  least  render  it  less  delicate. 

The  skin,  in  man,  is  more  bare  than  that  of  other  animals;  it  is,  like- 
wise, least  covered  with  insensible  parts  that  might  blunt  the  sense  of 
touch.  In  almost  all  mammiferous  animals,  the  whole  body  is  covered 
with  hair,  only  a  small  part  of  the  human  body  has  any  hair  on  it,  and 
that  in  too  snr«ll  a  quantity,  and  of  too  delicate  a  texture,  to  interfere 
with  the  touch.  Some  men,  however,  have  a  very  hairy  skin,  and  I  have 
seen  several  who,  when  naked,  looked  as  if  covered  over  with  the  skin  of 
an  animal,  so  great  was  the  quantity  of  hair  over  the  whole  body,  of 
which  no  part  was  bare,  but  a  small  portion  of  the  face,  the  palms  of  the 
hands,  and  the  soles  of  the  feet.  This  extraordinary  growth  of  hair,  is, 
in  general,  a  sure  sign  of  vigour  and  strength.  In  childhood  there  is  no 
hair  except  on  the  head,  the  rest  of  the  body  is  covered  with  down.  Wo- 
men have  no  beard,  and  there  is  in  them,  a  smaller  quantity  of  hair  in 
the  arm-pits  and  on  the  parts  of  generation,  and  scarcely  any  on  the  limbs 
and  trunk.  But  as  though  the  matter  which  should  provide  for  the  growth 
of  the  hair,  were  wholly  applied  to  the  hairy  scalp,  it  is  observed,  that 
their  hair  is  longer  and  in  greater  quantity. 

The  colour  of  the  hair  varies  from  white  to  jet  black;  and,  as  will  be 
mentioned,  in  speaking  of  the  temperaments  and  the  varieties  of  the  hu- 
man species,  this  difference  of  colour  is  a  test  by  which  we  judge  of  those 
varieties.  The  colour  of  the  hairs  enables  us  to  judge  of  their  thickness  : 
Williof,  who,  with  a  truly  German  patience,  was  at  the  pains  to  count 
how  many  hairs  were  contained  in  the  space  of  a  square  inch,  states,  in 
Ms  dissertation  on  the  human  hair,  that  there  are  five  hundred  and  seventy- 
two  black  hairs,  six  hundred  and  eight  chesnnt,  and  seven  hundred  and 
ninety  light  coloured,  so  that  the  diameter  of  a  hair,  which  is  between 
the  three  and  seven  hundredth  part  of  an  inch,  is  least  in  light  hair,  and 


*  The  toe  nails  are  favourable  lo  the  laying1  the  foot  to  the  surface  on  which  the  body 
is  supported ;  they,  likewise,  improve  the  sense  of  touch  in  this  part.  The  use  of  the 
feet  is  not  merely  to  support  the  \veight  of  the  body,  they  are  also  intended  to  guide  us 
in  feeling1  for  the  plane  on  which  we  are  to  rest  them,  to  enable  us  to  judge  of  the  solid- 
ity, of  the  temperature,  and  of  the  inequalities  of  the  ground  on  which  we  tread.  They, 
therefore,  required  rather  a  delicate  sense  of  touch.  The  division  of  the  fore  part  of  the 
foot,  into  several  distinct  and  separate  parts,  serves  to  enable  us  to  stand  more  firmly, 
and  facilitates  the  action  of  walking.  1  have  seen  several  soldiers  who  lost,  from  severe 
cold,  the  extremities  of  their  feet,  in  crossing  the  Alps  which  separates  France  from 
Italy.  Those  who  had  lost  only  their  toes,  did  not  walk  so  steadily,  and  frequently  fell 
in  treading  on  uneven  ground.  Those  who  had  lost  one  half  of  their  feet,  were  obliged 
to  use  crutches. — Author's 


264 

these  are  finer  the  lighter  their  shade.  It  is,  likewise,  observed^  that 
men  of  a  bilious  constitution,  with  dark  hair,  and  inhabiting  warm  cli- 
mates, have  more  hair,  in  other  parts  of  the  body,  and  that  it  is  coarser 
and  more  greasy. 

In  whatever  part  of  the  body  hairs  may  grow,  they  are,  every  where, 
of  the  same  structure,  they  all  arise  from  a  vesicular  bulb  in  the  adipose 
cellular  tissue;  from  this  bulb  containing  a  gelatinous  lymph,  on  which 
the  hair  seems  to  be  nourished,  the  latter,  at  first  divided  into  two  or 
three  filaments  which  constitute  a  kind  of  root,  comes  out  in  a  single 
trunk,  passes  through  the  skin  and  epidermis,  receiving  from  the  latter 
a  sheath  that  covers  it  to  its  extremity,  which  terminates  in  a  point. 

A  hair,  may,  therefore,  be  considered  as  an  epidermoid  tube  filled  with 
a  peculiar  kind  of  marrow.  This  spongy  stem,  which  forms  the  centre 
of  a  hair,  is  a  more  essential  part  of  it,  than  the  sheaths  supplied  by  the 
epidermis.  Along  this  spongy  and  cellular  filament,  the  animal  oil  of 
the  hair  and  the  juices  on  which  it  is  repaired  flow.  Though  we  see,  in 
some  animals,  vascular  branches  and  very  small  nervous  filaments  direct- 
ed towards  the  root  of  certain  kinds  of  hair,  and  lost  in  it,  as  is  the  case 
•with  the  long  and  stiff  whiskers  of  some  of  the  quadrupeds,  it  is  impos- 
sible to  say,  whether  in  man,  the  hair  or  its  bulbs  receives  vessels  and 
nerves.  Is  the  human  hair  nourished  by  the  imbibtion  of  the  gelatinous 
fluid  contained  in  its  bulb,  or  is  it  nourished  on  the  fat  in  which  the  lat- 
ter is  imbedded?  Are  vessels  distributed  along  their  axis,  from  the  root 
to  the  extremity  ?  In  favour  of  this  opinion,  it  was  usual  to  mention  the 
bleeding  from  the  hair  when  cut,  in  the  disease  called  plica  fiohnica.  But 
this  disease,  lately  observed  in  Poland,  by  tlie  French  physicians,  appear- 
ed to  them  a  mere  entangling  of  hair,  in  consequence  of  the  filth  of  the 
Poles,  and  of  their  habit  of  keeping  their  head  constantly  covered  with 
a  woollen  cap.  The  hairy  scalp  remains  perfectly  sound  beneath  the  en- 
tangled hair,  and  the  only  way  to  cure  the  complaint  is  to  cut  of  the  hair. 
Fourcroy*  thinks  that  each  hair  has  several  short  branches  that  stand  off 
from  it,  which,  according  to  the  explanation  given  by  Monge,  favour 
the  matting  of  the  hairs  that  are  to  be  converted  into  tissues,  by  the  pro- 
cess called  felting. 

CXXXIV.  Among  the  most  remarkable  qualities  of  the  hair  one  may 
take  notice  of  the  manner  in  which  it  is  affected  by  damp  air,  which,  by 
relaxing  its  substance,  increases  its  length.  It  is  on  that  account,  that 
hairs  are  used  for  the  construction  of  the  best  hygrometers.  NOT  must 
we  omit  either  the  readiness  with  which  they  grow  and  are  reproduced, 
even  after  being  plucked  out  by  the  roots,  as  I  have  often  seen  after  the 
cure  of  tinea  by  a  painful  method  :  nor  their  insulating  property,  with 
respect  to  the  electric  fluid,  of  which  they  are  vjery  bad  conductors ,  a 
remarkable  property,  vie.wed  with  reference  to  the  conjectured  nature  of 
the  nervous  fluid. 

The  hairs  possess  no  power  of  spontaneous  motion  by  which  they  can 
rise  on  the  head,  when  the  soul  shudders  with  horror  or  fear;  but  they 
do  bristle  at  those  times,  by  the  contraction  of  the  occipito-frontales, 
which,  intimately  adhering  to  the  hairy  scalp,  carries  it  along  in  all  its 
motions. 

They  appear  totally  without  sensibility  :  nevertheless,   the  passions 


Systems  des  connoissance  chimgues,  tome  IX.  p.  263. 


265 

have  over  them  such  influence,  that  the  heads  of  "young  people  have  turn- 
ed white  ^Jfcjae  night  before  execution.  The  Revolution,  which  pro- 
duced. inKiiBlance,  the  extremes  of  human  suffering,  furnished  many 
authentit^ftsXices  of  persons  that  grow  hoary,  in  the  space  of  a  few  days. 
In  this  pBp]J»re  hoariness,  is  the  hair  dried  up,  as  in  old  people,  when 
it  seems  twf^B01'  want  of  moisture  and  its  natural  juices  ? 

The  folwHg  fact  seems  to  show,  that  they  are  the  excretory  organ 
of  some  PflHRtej  the  retention  of  which  might  be  of  very  injurious  con- 
sequence. H  Bjhionk,  who,  every  month,  had  his  head  shaved,  accord- 
ing to  the^jMrof  his  order,  quiting  it  at  its  destruction,  went  into  the 
army,  and  let  his  hair  grow.  After  a  few  months,  he  was  attacked  with 
excruciating  head  aches,  which  nothing  relieved.  At  last  some  one  ad- 
vised him  to  resume  his  old  habit,  and  to  have  his  head  frequently  shav- 
ed ;  the  head  aches  went  off,  and  never  returned. 

We  know,  says  Grimaud*,  that  there  are' nervous  head  aches,  which 
give  way  to  frequent  cropping  the  hair: — when  it  is  kept  close  cut,  the 
more  active  growth  that  takes  place  sets  in  motion  stagnating  juices.  A 
friend  of  Valsalva,  as  MorgagjJM'  relates,  dispelled  a  maniacal  affection, 
by  having  the  head  of  the  patient  shaved;  Casimir  Medicus  cured  obsti- 
nate gonorrhea,  by  the  frequent  shavings  of  the  parts  of  generation. 

The  hairs  partake  of  the  inalterability,  the  almost  indestructibility  of 
the  epidermis.  Like  it,  they  burn  with  a  fizzing,  and  give  out,  in  abun-. 
dance,  a  fetid  ammoniacal  oil.  These  ashes,  that  remain  from  burning 
them,  contain  much  phosphate  of  limef.  The  horns  of  mammiferae,  the 
feathers  of  birds,  give  out  the  same  smell  in  burning  and  yield  the  same 
products  as  the  hair  on  the  head  and  other  parts;  which  has  led  to  the 
saying  that  these  last  were  a  .sort  of  a  horny  substance  drawn  out  like 
wire.  Acids,  but  especially  alkalies,  dissolve  them  :  accordingly,  all  na- 
tions that  cut  the  beard,  first  soften  it,  by  rubbing  it  with  alkaline  and 
soapy  solutions. 

Is  the  use  of  the  hair  to  evacuate  the  superabundant  nutritious  matter? 
The  epoch  of  puberty  and  of  the  termination  of  growth,  is  that  in  which 
it  first  springs,  in  many  parts  of  the  body,  which  were  before  without  it. 
They  are,  at  the  same  time,  the  emunctory  by  which  nature  gets  rid  of  the 
phosphate  of  lime,  which  is  the  residue  of  the  work  o?  nutrition.  The 
hairs  of  quadrupeds,  whose  urine  abounds  less  in  phosphoric  salts  than 
that  of  man,  seem  especially  to  fulfil  this  destination.  The  hairs  have 
some  analogy  with  the  fat,  which  has  not  yet  been  ascertained.  They  are 
often  found  accidentally  developed  in  the  fatty  tumours  known  under  the 
name  of  steatomas.  Finally,  they  have  uses  relative  to  the  parts  on  which 
they  grow. 

CXXXV.  The  faculty  of  taking  cognizance  of  tangible  qualities,  be- 
longs to  all  parts  of  the  cutaneous  organ.  We  have  only  to  apply  a  sub- 
stance to  any  part  of  the  surface  of  our  body,  to  acquire  the  idea  of  its 
temperature,  of  its  dryness  or  moisture,  of  its  weight,  its  consistence,  and 
even  its  particular  figure.  But  no  part  is  better  fitted  to  acquire  exact 
notions,  on  all  these  properties,  than  the  handy  which  has  ever  been  con- 
sidered as  the  especial  organ  of  touch.  The  great  number  of  bones 


*  Second  Memoir  on  Nutrition,  p.  49. 

f  -De  Sedibiis  et  Cansis,  Ernst.  8.  No.  7. 

t  See  the  Chapter  in  the  APPEXDIX,  on  the  chemical  constitution  of  the  textures,  Sec. 

2  L 


266 

that  form  its  structure,  make  it  susceptible  of  very  various  motion,  by 
\vhich  it  changes  its  form,  adapts  itself  to  the  ineciualities^Lthp  surfaces 
of  bodies,  and  exactly  embraces  them :  this  apt  confornJ^H|s  particu- 
larly manifest  at  the  extremities  of  the  fingers  Their  ante^^Brt,  which 
is  endued  with  the  most  delicate  feeling,  receives,  from  -dian  and 

cubital  nerves,  branches  of  some  size,  which  end  in  romidedrfcxtrernitics. 
close,  and  surrounded  with  a  cellular  tissue.  The  part  of  the  fingers, 
which  is  called  their  pulp,  is  supported  by  the  nails;  vIBps  in  great 
number  are  spread  through  this  nervo-cellular  tissue,  and  moisten  it  with 
abundant  juices,  that  keep  up  its  suppleness.  When  perspiration  is  in- 
creased, it  breaks  out,  in  small  drops,  over  this  extremity  of  the  fingers, 
along  the  hollow  of  the  concentric  lines  with  which  the  epidermis  is  fur- 
rowed*. 

It  has  been  attempted  to  explain  the  pleasure  we  feel  in  touching  round- 
ed and  smooth  surfaces,  by  showing  that  the  reciprocal  configuration  of 
the  hand  and  of  the  body  to  which  it  is  applied,  is  such,  that  they  touch 
in  the  greatest  number  of  points  possible.  The  delicacy  of  the  touch  is 
kept  up  by  the  fineness  of  the  epidern^s  :  it  increases  by  education, 
which  has  more  power  over  this  sense  Wn  over  any  of  the  others.  It 
is  known  with  what  eagerness  a  child,  allowed  the  free  use  of  his  limbs, 
stretches  his  little  hands  to  all  the  objects  within  his  reach,  whatjpleasurc 
he  seems  to  take  in  touching  them,  in  all  their  parts,  and  running  over  all 
their  surfaces.  Blind  men  have  been  known  to  distinguish,  by  touch, 
the  different  colours,  and  even  their  different  shades.  As  the  difference 
of  colour  depends  on  the  disposition,  the  arrangement,  and  the  number 
of  the  little  inequalities,  which  roughen  the  surface  of  bodies  that  ap- 
pear the  most  polished,  and  fit  them  to  reflect  such  a  ray  of  light,  absorb- 
ing all  the  others,  one  does  not  refuse  to  believe  facts  of  this  kind,  related 
by  Boyle,  and  other  Natural  Philosophers. 

Some  parts  appear  endowed  with  a  peculiar  touch;  such  ure  the  lips, 
whose  tissue  swells,  and  spreads  out  under  a  voluptuous  contact;  a  vital 
turgescence,  explicable  without  the  supposition  of  a  spongy  tissue  in  their 
structure: — such  are  those  organs  which  Buffon  considers  as  the  seat  of 
a  sixth  sense.  In  most  animals,  the  lips,  and  especially  the  lower  one, 
without  feathers,  scales,  or  hair,  are  the  organs  of  a  sort  of  touch,  imper- 
fect at  best.  When  the  domestic  quadrupeds,  such  as  the  horse,  the  dog, 
the  ox,  Sec.  want  to  judge  of  the  tangible  qualities  of  bodies,  you  will 
see  them  apply  to  it  the  end  of  their  nose,  the  only  part  where  the  exter- 
nal coffering  is  without  hsiir;  the  fleshy  appendages  of  certain  birds,  and 
many  fish  with  the  antennae  of  butterflies,  always  set  near  the  opening  of 
the  mouth,  answer  the  same  purpose.  The  tail  of  the  beaver,  the  trunk  of 
the  elephant,  are  in  like  manner,  ihe  parts  of  their  body  where  the  touch 
is  most  delicate.  Observe  that  the  perfection  of  the  organ  of  touch,  en- 
sures to  these  two  animals  a  degree  of  intelligence  allotted  to  no  other 


*  The  use  of  the  peculiar  lines  of  the  epidermis,  especially  over  the  inside  of  the 
lingers  and  palms  of  the  hand,  is  rendered  very  evident  by  the  effect  of  blisters  which 
sometimes  cause  an  entire  exfoliation  of  ihis  texture.  The  new  formed  epidermis  in 
many  instances  is  smooth  and  shining1,  and  the  finger  cannot  for  a  considerable  time  be 
flexed  with  case,  until  permanent  folds  are  formed  in  the  integuments  by  frequent  at- 
tempts to  bend  the  finger.  After  some  weeks  a  new  epidermis  is  formed,  having  the 
the  proper  lines  ;  and  the  parts  are  bent  in  every  direction,  without  irregular  doublings 
of  the  skin — Godmav- 


267 

quadruped,  and  becomes  perhaps  the  principle  of  their  sociability.  The 
books  of  travellers  and  naturalists  swarm  with  facts,  attesting  the  won- 
derful sagacity  of  the  elephant.  Some  Indian  philosophers  have  gone  the 
length  of  allowing  him  an  immortal  soul.  If  birds,  notwithstanding  the 
prodigious  activity  of  their  life  of  nutrition,  are  yet  of  such  confined  in- 
telligence, so  little  susceptible  of  durable  attachment,  so  restive  to  educa- 
tion, is  not  the  cause  to  be  assigned  to  their  imperfection  of  touch  ?  In  vain 
the  heart  sends  towards  all  their  organs,  with  more  force  and  velocity 
than  any  other  animal,  a  warmer  blood,  and  endued,  more  remarkably, 
with  all  the  qualities  which  characterize  arterial  blood.  In  vain  is  their 
digestion  rapid,  their  muscular  power  lively,  and  capable  of  long  continu- 
ed motion;  certain  of  their  senses,  as  those  of  sight  and  hearing,  happi- 
ly disposed;  touch  being  almost  nothing  with  them,  as  also  the  greater 
number  of  impressions  belonging  to  this  sense,  which  informs  us  of  the 
greater  part  of  the  properties  of  bodies;  the  circle  of  their  ideas  must 
be  extremely  narrow,  and  their  habits,  and  manners,  much  more  remote 
than  those  of  quadrupeds,  from  the  habits  and  manners  of  man. 

CXXXVI.  Of  all  the  senses,  the  touch  is  the  most  generally  diffused 
among  animals.  All  possess  it.  from  man,  who,  in  the  perfection  of  this 
sense,  excels  all  the  vertebral  animals,  to  the  polypus,  who,  confined  to 
the  sense  of  touch  only,  has  it,  in  such  delicacy,  that  he  appears,  to  use 
a  happy  expression  of  M.  Dumeril,  to  feel  even  light.  The  skin  of  man 
is  more  delicate,  fuller  of  nerves  than  that  of  the  other  mammiferas:  its 
surface  is  covered  only  by  the  epidermis,  insensible  indeed,  but  so  thin 
that  it  does  not  intercept  sensation,  whilst  the  hairs  which  cover  so  thick- 
ly the  bodies  of  quadrupeds,  the  feathers  which*  clothe  that  of  birds,  quite 
deaden  it.  The  hand  of  man,  that  admirable  instrument  of  his  intelli- 
gence, of  which  the  structure  has  appeared  to  some  philosophers*  to  ex- 
plain sufficiently  his  superiority  over  all  living  species:  the  hand  of  man, 
naked,  and  divided  into  many  moveable  parts,  capable  of  changing, 
every  moment,  its  form,  of  exactly  embracing  the  surface  of  bodies,  is 
much  fitter  for  ascertaining  their  tangible  qualities,  than  the  foot  of  the 
quadruped  enclosed  in  a  horny  substance,  or  than  that  of  the  bird,  covered 
with  scales  too  thick  not  to  blunt  all  sensation. 

CXXXVII.  Of  the  nerves.  These  whitish  cords,  which  arise  from  the 
base  of  the  brain,  and  from  the  medulla  oblongata,  are  distributed  to  all 
parts  of  the  body;  and  give  them,  at  once,  the  power  of  moving  and  feel- 
ing. In  this  analysis  of  the  functions  of  the  i>ervous  system,  the  most 
natural  order  is  to  consider  them  merely  as  conductors  of  the  power  of 
sensation.  We  shall  then  see,  in  what  manner  tfiey  transmit  the  princi- 
ple of  motion  to  the  organs  by  which  it  is  performed.  The  nerves  arisef 
from  the  sentient  parts,  by  the  extremities  that  are,  in  general,  soft  and 


*  See  the  work  of  Galen,  de  usu  partium,  cap.  4,  5,  6,  and  BuflTon,  Histoii".  C\'ulureUe 
torn.  IV.  etV.  12mo. 

y  In  considering  the  nerves  as  conductors  of  sensation,  it  is  correct  to  say,  that  they 
arise  from  sentient  parts,  since  it  is  the  extremity  rnost  distant  from  the  brain,  \vhich 
experiences  the  sensitive  imjnvssion,  that  it  is  propagated  to  the  organ  itself,  along-  the 
course  of  the  nerve.  In  attending,  on  the  contrary,  to  tue  phenomena  of  motion,  the 
nerves  are  considered  to  arise  from  the  brain  ;  for]  it  is>  from  the  centre  of  the  circum- 
ference, thst  the  principle  of  motion  is  transmitted  to  the  muscles  called,  by  Cullen, 
moving  extremities  of  the  nerves.  Some  anatomists  have  considered  it  as  a  doubtful  point', 
whether  the  nerves  arise  from  the  brain  and  spinal  marrow,  or  whether  these  parts  are 
formed  by  the  union  of  the  nerves.—  Authors  Note. 


268 

pulpy,  but  not  alike  in  all,  in  consistence  and  form ;  and  it  is  to  these  va- 
rieties of  arrangement  and  structure,  that  the  varieties  of  sensation  in 
the  different  organs  are  to  be  referred. 

One  may  say  that  there  exists,  in  the  organs  of  sense,  a  certain  relation, 
between  the  softness  of  the  nervous  extremity,  and  the  nature  of  the  bo- 
dies which  produce  an  impression  upon  it.  Thus,  the  almost  fluid  state 
of  the  retina,  bears  an  evident  relation  to  the  subtilty  of  light.  The  con- 
tact of  this  fluid  could  not  produce  a  sufficient  impression,  unless  the 
sentient  part  were  capable  of  being  set  in  motion  by  the  slightest  im- 
pression. The  portio  mollis  of  the  seventh  pair,  wholly  deprived  of  its 
solid  covering,  and  reduced  to  its  medullary  pulp,  readily  partakes  in  the 
sonorous  motions  transmitted  to  it  by  the  fluid,  in  the  midst  of  which  its 
filaments  are  immersed.  The  nerves  of  smell  arid  of  taste  are  more  ex- 
posed, than  the  nervous  papillae  of  the  skin  employed  in  receiving  the 
impressions  produced  by  the  coarser  properties  of  bodies,  See. 

From  their  origin,  the  nerves  ascend  towards  the  medulla  oblongata 
and  the  spinal  marrow,  in  a  line  nearly  straight,  and  seldom  tortuous,  as 
most  of  the  vessels.  When  they  have  reached  these  parts,  they  termi- 
nate in  them  and  are  lost,  in  their  substance,  as  will  be  mentioned,  in 
speaking  of  the  structure  of  these  nervous  cords. 

CXXXVIII.  Every  nerve  is  formed  of  a  greater  number  of  filaments, 
extremely  delicate,  and  which  have  two  extremities,  the  one  in  the  brain 
and  the  other  from  the  part  in  which  they  terminate,  or  from  which  they 
originate.  Each  of  these  nervous  fibres,  however  minute,  is  composed 
of  a  membranous  tube,  which  is  a  production  of  the  pia  mater.  Within 
the  parietes  of  this  tube,  there  are  distributed  innumerable  vessels  of 
extreme  minuteness:  it  is  filled  with  a  whitish  marrow,  a  kind  of  pulp, 
which  Reil  states  he  insulated  from  the  small  canal  containing  it,  by  con- 
creting it,  by  means  of  the  nitric  acid,  which  dissolves  the  membranous 
sheath,  and  leaves  uncovered  the  medullary  pulp  forming  the  essential 
part  or  basis  of  the  nervous  filament.  The  same  physiologist  discovered, 
by  a  different  process,  the  internal  structure  of  each  nervous  fibrilla;  he 
dissolved  the  whitish  or  pulpy  part,  by  a  long  continued  solution  in  an 
alkaline  ley,  and  he  succeeded  thus  in  separating  it  from  the  membranous 
tube  which  enclosed  it  and  which  was  emptied.  The  membranous  sheath 
is  of  cellular  structure,  and  is  remarkable  only  by  its  consistence  and  by 
the  very  considerable  number  of  vessels  of  all  kinds  that  are  distributed 
to  its  parietes;  it  ceases  to  cover  the  nerves  near  their  two  extremities, 
and  protects  them  only  along  their  course. 

Each  nervous  fibre,  thuss  formed  of  two  very  distinct  parts,  joins  other 
fibres  of  a  perfectly  similar  structure,  to  form  a  nervous  filament  enve- 
loped in  a  common  sheath  of  cellular  tissue.  These  filaments  by  their 
union,  form  small  ramifications,  and  those  progressively  larger  branches, 
and  lastly,  trunks  w?  apped  in  a.  common  covering  of  cellular  tissue;  then 
other  envelopes  to  each  fasiculus  of  filaments,  and  lastly,  a  sheath  to  each 
individual  filament.  When  nervous  cords  are  of  a  certain  size,  veins  and 
arteries  of  a  pretty  considerable  calibre,  may  be  seen  to  insinuate  them- 
selves between  the  bundles  of  fibres  of  which  they  are  composed;  these 
vessels  then  divide,  after  penetrating  among  them,  and  furnish  the  capil- 
lary ramifications  which  are  distributed  to  the  parietes  of  the  sheath 
common  to  each  filament.  These  small  vessels,  according  to  Reil,  allow 
the  nervous  substance,  to  exhale  into  each  membranous  tube;  this,  like- 
wise, becomes  the  secretory  organ  of  the  medulla  with  which  it  is  filled. 


269 

•  CXXXIX.  The  nervous  filaments  unite,  or  are  separated  from  one 
another,  but  do  not  run  into  each  other.  The  divisions  of  the  nerves  are 
different  from  those  of  the  arteries,  and  their  mode  of  junction  does  not 
admit  of  being  compared  to  that  of  the  veins.  It  is,  in  the  first  instance, 
a  mere  separation;  in  the  second,  an  approximation  of  filaments  which  had 
been  separated,  and  which,  though  united  in  common  sheaths,  have,  ne- 
nertheless,  each  a  proper  covering,  are  merely  in  juxta-position  and  per- 
fectly distinct.  If  that  were  not  the  case,  one  could  not  say,  that  each 
fibre  has  one  extremity  in  the  brain,  and  the  other  in  some  one  point  of 
the  body;  nor  could  one  conceive  how  the  impressions  which  several 
sentient  extremities  receive  at  once,  reach  the  brain  without  running 
into  each  other:  nor,  in  what  manner  the  principle  of  motion  could  be 
directed  towards  a  single  muscle  receiving  its  nerves  from  the  same  trunk 
as  the  other  muscles  of  the  limb. 

In  general,  the  nerves  divide  from  each  other  and  unite  at  an  angle 
more  or  less  acute,  and  equally  favourable  to  the  circulation  of  a  fluid, 
from  the  circumference  to  the  centre,  and  from  the  centre  to  the  circum- 
ference. 

The  structure  of  the  nerves  is  different  according  to  their  situation. 
Thus,  the  medullary  fibres  of  the  optic  nerve  are  not  furnished  with  mem- 
branous coverings,  the  pia  mater  alone  furnishing  a  sheath  to  the  cord 
formed  by  the  union  of  these  filaments;  the  dura  mater  adds  a  second 
coat  to  it,  on  its  leaving  the  skull.  This  coat,  belonging,  likewise,  to  the 
whole  nerve,  is  not  continued  over  it,  after  it  has  entered  the  eye-ball, 
and  is  lost  in  the  sclerotica.  A  minute  artery  passes  through  the  centre 
of  the  optic  nerve,  and  then  dividing,  forms  a  rete  mirabile  which  sup- 
ports, the  medullary  pulp  of  the  retina.  The  nerves  which  pass  along 
osseous  canals,  as  the  Vidian  nerve  of  the  fifth  pair,  are  not  provided 
with  a  cellular  covering,  and  their  consistence  is  always  greater  than  that 
of  the  nerves  which  are  surrounded  by  soft  parts. 

CXL.  On  reaching  the  brain,  the  medulla  oblongata,  or  the  spinal 
marrow,  every  nervous  filament,  as  was  already  mentioned,  parts  with  its 
membranous  covering,  which  is  lost  in  the  pia  mater,  or  immediate  co- 
vering of  these  central  parts  of  the  brain.  The  medullary  or  white  part 
of  the  brain  is  continued  into  their  substance,  which  may  be  considered 
as  principally  formed  by  the  assemblage  of  these  nervous  extremities 
which  it  is  difficult  to  distinguish  in  its  tissue,  from  its  want  of  consist- 
ence. It  has  long  been  known,  that  the  origin  of  the  nerves  is  not  the 
spot  at  which  they  are  detached  from  the  brain,  that  they  sink  into  the 
substance  of  this  viscus,  in  which  their  fibres  cross  each  other  so  that 
those  on  the  right  pass  to  the  left,  and  vice  versa.  Scemmering  thought, 
that  the  roots  of  the  nerves,  especially  of  the  nerves  of  the  organs  of 
sense,  reached  to  the  prominences  in  the  parietes  of  the  ventricles  of  the 
brain,  and  that  their  furthest  extremity  was  moistened  by  the  serosity 
which  keeps  these  inward  surfaces  in  contact.  It  has  likewise  long  been 
thought,  that  the  cerebral  extremities  of  the  nerves  all  joined  in  a  fixed 
point  of  the  brain,  and  that  to  this  central  point  all  sensations  were  car- 
ried, and  that  from  it  all  the  determinations  producing  voluntary  motion 
arose.  But  the  inquiries  of  Gall  on  the  structure  of  the  brain  and  ner- 
vous system,  have  completely  overset  these  various  hypotheses. 

The  spinal  marrow  and  the  nerves,  in  the  different  animals  furnished 
with  them,  are  larger  in  proportion  to  the  brain,  according  as  the  animal 
is  more  distant  from  man  in  the  scale  of  animation.  In  carnivorous 


270 

animals,  the  prodigious'developement  of  the  muscles  required  nerves  of 
motion  of  a  proportionate  size;  hence,  in  them,  the  cerebral  mass,  com- 
pared to  the  nerves  and  spinal  marrow,  is  very  inconsiderable.  It  is  ob- 
served, that  there  exists  the  same  relation,  in  men  of  an  athletic  dispo- 
sition ;  the  whole  nervous  power  seems  employed  in  moving  their  large 
muscles,  and  the  nerves,  though  very  small  in  proportion  to  the  rest  of 
the  body,  are,  however,  very  large,  if  compared  to  the  cerebral  organ. 
In  children,  in  women,  and  individuals  possessed  of  much  sensibility,  the 
nerves  are  very  large  in  proportion  to  the  other  parts  of  the  body,  they 
decrease  in  size  and  shrink  in  persons  advanced  in  years;  the  cellular 
tissue  which  surrounds  them,  becomes  more  consistent,  adheres  to  them 
more  closely;  and  there  exists  a  certain  analogy  between  the  nerves  of 
old  men,  enveloped  by  that  yellowish  tissue,  which  makes  their  dissection 
laborious,  and  the  branches  of  an  old  tree  covered  over  by  a  destructive 
moss. 

As  the  uses  of  the  nerves  cannot  be  explained  independently  of  those 
of  the  brain,  I  shall  now  go  on  to  consider  this  important  viscus. 

CXLI.  Of  the  spinal  cord,  and  its  functions*.  This  part  of  the  nervous 
system  ought  no  more  to  be  called  the  spinal  prolongation  of  the  ence- 
phalon,  as  it  has  been  by  some  writers,  than  it  ought  to  be  named  the 
spinal  marrow:  both  designations  are  equally  erroneous.  It  is  indepen- 
dent of  the  encephalic  organ.  As  the  central  portion  of  the  nervous 
system,  it  is  to  be  found  in  many  animals  which  possess  no  brain,  and 
its  volume  is  not  proportionate  to  that  of  this  organ.  The  ox,  horse,  and 
sheep,  for  example,  which  have  smaller  brains  than  man,  have  a  much 
larger  spinal  cord.  It  is  found  in  acephalous  foetuses,  where  the  brain 
never  existed.  This  latter  organ  appears  to  be  superadded  to  it,  and  that 
only  in  the  perfect  animals,  its  proportionate  size  being  always  in  an  in- 
verse ratio  to  the  spinal  cord.  This  part  of  the  nervous  system  cannot, 
therefore,  be  considered  as  a  production  from  the  brain,  and  as  formed 
by  a  collection  of  nerves  which  successively  detach  themselves  from  it. 
Its  volume  does  not  gradually  diminish,  owing  to  the  nerves  which  it 
sends  off';  and  instead  of  presenting  the  characters  of  a  cord  which  gra- 
dually decreases  in  thickness  as  it  advances  from  the  brain,  it  consists  of 
a  set  of  knots,  bulbs,  or  separate  prominences,  equal  in  number  to  the 
pairs  of  nerves  which  arise  from  it. — Finally,  the  spinal  marrow  is  formed 
in  the  foetus  before- either  cerebellum  or  cerebrum;  these  organs  proceed- 
ing from  it,  and  not  it  from  them.  About  the  second  month  of  the  foetal 
existence,  the  first  epoch  at  which  the  brain  can  be  rendered  apparent 
by  the  action  of  alcohol,  this  organ  is  uncommonly  small  in  proportion 
to  the  size  of  the  spinal  marrow,  and  arises  evidently  from  a  prolonga- 
tion of  the  pyramidal  eminences  and  the  corpora  oblivaria.  The  different 
parts  of  the  encephalic  mass  are  gradually  formed  by  the.  successive  de- 
velopement  of  the  corpora  pyramidalia,  and  it  is  only  towards  the  end  of 
gestation,  that  the  hemispheres  are  fully  formed!- 

The  special  functions  that  may  be  assigned  to  the  spinal  cord,  are  dif- 
ferent from  those  performed  by  the  brain.  In  the  spinal  marrow  resides 
the  source  of  all  the  movements,  both  voluntary  and  involuntary,  that  are 
performed  by  the  animal  economy:  it  presides  over  those  of  the  heart,  of 

*  The  whole  of  this  section  has  been  translated  from  the  last  French  edition  of  this 
work. —  Copland. 
+  See  APPENDIX,  Note  D  D. 


271 

of  all  the  muscles  of  the  interior  life,  as  well  as  over  those  of  the  loco- 
motive apparatus;  and  while  the  brain,  reserved  for  the  most  noble  and 
most  important  functions,  seems  exclusively  charged  \vilh  the  operations 
of  intelligence  and  thought,  the  spinal  marrow  holds  under  its  controul 
all  the  contractile  organs,  and  it  is  by  its  influence  that  all  their  contrac- 
tions are  executed*. 

Thomas  Bartholin  had  already  acknowledged  that  the  brain  was  more 
particularly  the  organ  of  sensation,  and  the  spinal  marrow  that  of  mo- 
tionf.  He  v/as  equally  sensible,  that  the  best  way  of  proceeding  in  the 
dissection  of  the  brain,  was  to  advance  from  the  base  to  the  vertex,  and 
not  from  the  summit  to  the  base,  as  was  the  custom  until  our  times. 

If  we  take  a  view  of  the  graduated  scale  of  the  animal  creation,  says  Dr. 
Gall,  in  his  Researches  of  the  Nervous  System,  Sec.  the  sensible  substance, 
which  is  merely  gelatinous  pulp  in  the  polypus,  gradually  becomes  dis- 
posed into  nervous  filaments  and  cords  hi  the  more  perfect  animals.  In 
order  to  establish  a  more  extended  intercourse  with  the  external  world, 
Nature  has  added  more  complex  organs,  according  as  the  relation  of  the 
species  with  the  surrounding  creation  become  more  numerous  :  it  is  thus 
that,  by  the  successive  addition  of  new  organs,  and  the  perfection  of 
others,  the  animal  creation  is  elevated  to  man  himself. 

The  brain,  a  simple  tubercle  added  to  the  anterior  extremity  of  the 
spinal  marrow,  of  which  it  seems  to  be  nothing  else  than  an  accessary 
part,  an  appendix,  in  the  insects,  because  amongst  them  it  is  but  little 
larger  than  one  of  their  numerous  ganglions,  becomes  more  complex  and 
more  perfect  in  the  higher  animals :  in  the  fishes  it  but  little  exceeds  the 
spinal  cord  ;  whilst  in  the  mammalia  it  possesses  the  same  parts  as  in 
man,  and  is  disposed  nearly  in  the  same  form ;  but,  in  no  animal  is  the 
double  appearance  of  diverging  and  converging  fibres  better  developed 
than  in  him  ;  in  no  other  animal  w  the  brain  properly  so  called,  that  is  to 
say,  the  superior  part  of  the  encephalon,  or  the  hemispheres,  possessed 
of  a  greater  volume  in  proportion  to  the  size  of  the  animalj.  The  brain 
proper  seems  to  be  the  seat  of  the  nobler  functions  of  intelligence,  whilst 
in  the  cerebellum  the  medulla  oblongata,  and  the  spinal  cord,  those  fa- 
culties and  manifestations  that  are  common  to  us  and  the  lower  animals, 
appear  to  reside. 

The  nervuos  system  ought  not,  therefore,  to  be  compared  to  a  tree,  the 
trunk  of  whichf  represented  by  the  spinal  marrow,  has  its  roots  in  the 
brain,  and  expands  its  branches  through  all  parts  of  the  body;  but  ought 
rather  to  be  considered  as  a  net-work  whose  threads  communicate  with 
each  other,  separate,  re-unite,  and  join  several  masses  or  dilatations  of 
greater  or  less  size:  these  masses  or  ganglions  ought  to  be  viewed  as 
being  the  centres  of  communication. 

The  brain  should  not  be  considered  as  a  ganglion,  or  even  as  a  collec- 
tion of  ganglions,  as  the  common  ganglion  of  the  nerves  of  the  cranium, 
as  some  physiologists  have  done;  the  nerves  which  detach  themselves 
from  its  base,  or  from  the  medulla  oblongata,  have  their  origins  distinct 


*  See  the  above  Note  i 
f  "  Et  id  quidem  manifestius  fit  inspicientibus  anatomen  piscium;  ibi  enim  medulla? 
caput  et  caucla  insij.niis  est  magnitudinis;  processus  vero  medullas  ad  cerebrum  admo- 

nocl  pisces  motu  magis  quam  sen 
cortex,  ad  motum  plus  medulla  i 


dum  exigunm,  cujus  rei  causa  est,  quod  p'isces  motu  magis  quam  sensu  utantur,  ac  sic 
ad  sensum  plus  conferat  cerebrum  vel 


See  APPENDIX,  Note  D  I). 


from  its  substance.  Their  volume  has  no  relations  to  its  bulk,,%ut  are 
proportionate  to  the  perfection  of  the  different  senses,  in  the  various  spe- 
cies of  animals;  thus,  the  olfactory  nerve,  which  is  very  large  in  the  mole, 
is  small  in  the  eagle,  while  the  optic  nerve  is  on  the  contrary  largely  de- 
veloped in  the  latter. 

The  spinal  marrow  may  be  considered  as  a  series  of  ganglions.,  com- 
municating with  each  other  and  with  the  brain*.  These  ganglions  are 
of  a  size  proportionate  to  that  of  the  nerves  which  originate  from  them. 
It  is  owing  to  this  that  the  spinal  marrow  is  thicker  towards  the  inferior 
part  of  the  cervical  and  dorsal  regions,  than  in  other  portions  of  its 
length.  Can,  therefore,  the  vertebral  column  be  compared  to  a  Galva- 
nic pile,  of  which  the  spinal  cord  is  the  conductor,  of  which  the  brain 
and  the  parts  of  generation  form  the  two  extremities^  and  constitute,  in 
a  manner,  the  two  poles  of  this  kind  of  electro-motive  apparatus  ?  Ob- 
servation establishes,  it  may  be  said,  a  sort  of  antagonism  between  these 
two  organs.  Is  there  any  analogous  opposition  existing  between  the  ce- 
rebral nervous  system  and  that  which  forms  the  grand  sympathetic 
nerves?  We  have  formerly  remarked  more  than  once,  how  ill  founded 
this  attempt  at  identifying  the  vital  phenomena  with  those  of  electricity, 
appears  to  us. 

The  commnuication  of  the  spinal  marrow  with  the  brain  is  established 
by  the  medium  of  a  double  bundle  of  fibres  which,  crossing  each  other, 
form  the  copora  pyramidalia,  and  direct  themselves  towards  the  brain, 
where  we  shall  find  them  again  when  the  structure  of  this  viscus  comes 
under  consideration. 

CXLII.  Of  the  coverings  of  the  brain.  If  it  be  true,  that  one  may  judge 
of  the  importance  of  an  organ,  by  the  care  which  nature  has  taken  to 
protect  it  from  external  injury,  no  organ  wi^l  appear  of  greater  impor- 
tance than  the  brain,  for,  no  one  app:e1?P9Ho  have  been  protected  with 
greater  care.  The  substance  of  this  viscus  has  so  little  consistence,  that 
the  slightest  injury  would  have  altered  its  structure,  and  deranged  its 
action ;  hence  it  is  powerfully  guarded  by  several  envelopes,  the  most 
solid  of  which,  is  the  bony  case,  in  which  it  is  contained. 

No  part  of  anatomy  is  better  understood,  than  that  of  the  many  bones 
which,  by  their  union,  form  the  different  parts  of  the  human  head. 
Every  thing  that  relates  to  the  place  they  occupy,  to  their  respective 
size,  to  their  projections  and  depressions  to  the  cavities*whose  parietes 
they  form,  every  thing  that  relates  to  their  internal  structure,  to  the  dif- 
ferent proportions  of  their  component  parts,  to  the  aggregation  of  some 
of  these  substances,  in  certain  points  of  their  extent,  has  been  described 
by  several  modern  anatomists,  with  an  accuracy  which  it  would  not  be 
easy  to  surpass.  Several,  however,  have  not  sufficiently  appreciated  the 
direct  influence  of  their  mode  of  union  on  the  purposes  which  they  are 
destined  to  fulfil ;  no  one  has  insisted  sufficiently  on  the  manner  in  which 
they  all  concur  to  a  principle  object ;  the  preservation  of  the  organs  en- 
closed within  the  skull. 

Hunauld,  in  a  memoir  inserted  among  those  of  the  Academy  of  Sciences, 
for  the  year  1730,  was  the  first  that  endeavoured  to  account  for  the  ar- 
rangement of  the  articulating  surfaces  of  the  bones  of  the  skull.  After 
laying  down  a  few  principles  on  the  theory  of  arches,  and  after  showing, 


See  APPENDIX,  Note  D  D. 


273 

y 

that  the  difference  of  extent  of  their  concave  and  convex  surfaces,  renders 
it  necessary  that  the  parts  of  which  they  are  formed,  should  be  shaped 
obliquely,  he  explains  the  advantages  of  the  sqaamous  articulation  be- 
tween the  temporal  and  parietal  bones. 

When  the  arch  of  the  cranium  is  loaded  with  a  very  heavy  burthen, 
the  temporal  bones  prevent  the  parietals  on  which  the  effort  is  immedi- 
ately applied,  from  being  forced  inwardly,  or  from  being  separated  out- 
wardly. Hunauld  very  aptly  compares  them  to  buttresses  which  are  to 
the  parietal  bones  of  the  same  use  as  walls  to  the  arches  which  they  sup- 
port. 

Bordeu*  endeavoured  to  apply  to  the  bones  of  the  face,  the  principles 
by  which  Hunauld  has  been  guided  in  his  investigation  with  regard  to 
those  of  the  skull.  According  to  Bordeu,  the  greater  part  of  the  bones 
of  the  upper  jaw,  but  particularly  the  superior  maxillary  bones,  resist  the 
effort  of  the  lower  jaw,  which,  by  acting  on  the  upper  dental  arch,  has  a 
perpetual  tendency  to  force  upward,  or  to  separate  outwardly,  the  bones 
in  which  the  teeth  of  that  ja\v  arc  inserted.  As  the  greatest  stress  of  the 
effort  determines  them  upward,  it  is,  likewise,  in  that  direction,  that  the 
bones  of  the  upper  jaw  rest  more  powerfully  on  those  of  the  skull.  The 
author  concludes  this  very  ingenious  memoir,  by  proposing  to  physiolo- 
gists, the  solution  of  the  following  problem,  "  When  a  man  supports  a 
great  weight  on  his  head,  and  holds  at  the  same  time  any  thing  very 
firmly  between  his  teeth,  which  is  the  bone  of  the  head  that  is  most 
acted  upon ;  which  supports  the  weight  cf  the  whole  machine  ?" 

The  body  of  the  sphenoid,  and  especially  the  posterior  half,  appears 
to  me  to  be  the  central  point  on  which  the  united  efforts  of  the  bones  of 
the  skull  and  of  the  face  act,  in  the  case  supposed  by  Bordeu. 

The  sphenoid  is  connected  with  all  the  other  bones  of  the  skull ;  it  is 
immediately  connected  with  several  of  the  bones  of  the  face,  as  with  the 
malar  bones,  with  the  palatine  bones,  with  the  vomer,  and  sometimes, 
with  the  superior  maxillary  bones.  These  bones  of  the  face,  in  the  case 
in  question,  alone  support  the  lower  jaw  against  the  upper.  The  ethmoid 
bone,  the  ossa  unguis,  and  the  inferior  turbinated  bones,  are  thin  and  frail, 
and  serve  merely  to  form  the  nasal  fossae,  of  which  they  increase  the 
windings,  and  do  not  deserve  to  be'  attendee^*  to  in  this  investigation. 
The  vomer  may,  it  is  true,  communicate  to  the  ethmoid,  in  an  inferior 
degree,  a  part  of  the  effort;  for,  the  anterior  part  of  its  upper  edge  is 
articulated  with  the  perpendicular  lanffclla  of  that  bone ;  but  this  quan- 
tity is  very  small,  as  the  vomer  is  thin  and  transmits  it  almost  wholly, 
to  the  body  of  the  sphenoid,  with  the  lower  face  of  which  it  is  articu- 
lated. 

The  effort  exerted  on  the  bones  of  the  upper  jaw,  is  transmitted,  by 
means  of  the  nasal  processes  of  the  upper  maxillary  bones,  by  the  orbital*- 
and  zygomatic  processes  of  the  malar  bones,  and  by  the  upper  edge  of  the 
palate  bones  and  of  the  vomer,  to  the  frontal,  to  the  temporal,  and  sphenoi- 
dal  bones. 

If  we  wish  to  determine  what  becomes  of  the  greater  part  of  the  effort 
transmitted  to  the  frontal  bones  by  the  maxillary  and  malar  bones,  we  may 
observe  in  the  first  place,  that  it  is  articulated  with  the  sphenoid  bone,  by 


*  Academe  des  Sciences,  Memoircs  presentes  par  les  savans  strangers.    Tome  EL 

2M 


274 

tlie  whole  of  its  lower  edge  which  is  bevelled  at  its  inner  part,  so  that  it 
is  covered  by  the  alse  minores  of  the  os  sphenoides,  which  is  shaped  ob- 
liquely at  the  outer  part  of  the  bone.  The  frontal  bone  is  articulated,  be- 
sides, with  the  lateral  and  inferior  parts  of  its  upper  edge.  The  remain- 
der of  this  upper  part  is  united  to  the  anterior  edge  of  the  parietal  bones, 
which  by  means  of  a  slope,  in  a  different  direction,  rest  on  the  middle 
part  of  this  edge,  while  the  frontal  bone  is  applied  to  them  laterally. 

This  bone  which  the  effort  tends  to  force  upward  and  backward,  can- 
not yield  to  this  double  impulse,  for,  on  the  one  hand,  its  mode  of  articu- 
lation with  the  anterior  edge  of  the  alae  minores  of  the  sphenoidal  bone, 
and  the  internal  -part  of  the  anterior  edge  of  the  parietal  bones,  resist 
this  tendency  upward,  while  the  resistance  from  the  latter,  prevents  them 
from  being  forced  backward.  That  share  of  the  effort  which  affects  the 
parietal  bones,  follows  the  curved  lines  described  by  these  bones,  and  ex- 
tends along  that  formed  by  the  occipital,  and  thus  reaches  the  posterior 
face  of  the  body  of  the  sphenoid  bone. 

The  portion  directly  transmitted  by  the  anterior  and  inferior  face  of 
this  bone,  by  the  ossa  palati  and  by  the  vomer,  is  considerable  and  pro- 
portioned to  their  thinness.  The  anterior  half  of  the  body  of  the  sphe- 
noid bone,  hollowed  by  the  sphenoidal  sinus,  would  have  been  incapable 
of  supporting  greater  pressure.  Lastly,  the  situation  of  the  body,  placed 
between  the  dental  arches,  in  front  of  the  place  occupied  by  the  ossa  pa- 
lati, explains  why  this  transmission  is  chiefly  effected  by  the  upper  maxil- 
lary bones. 

The  above  is  the  manner  in  which  the  effort  exerted  from  below  up- 
ward, by  the  lower  on  the  upper  jaw,  is  carried  to  the  anterior,  posterior, 
and  inferior  faces  of  the  body  of  the  sphenoid  bone. 

The  temporal  bones  which  are  affected  by  it,  in  a  very  slight  degree, 
by  means  of  the  zygomatic  processes  of  the  malar  bones,  support  the 
greater  weight  of  the  effort  acting  from  above  downward,  or  from  the 
arch  of  the  skull  towards  its  base.  The  weight  laid  on  the  head,  tends 
to  depress  or  to  separate  the  parietal  bones,  which  resist  the  pressure,  in 
consequence  of  the  support  afforded  them  by  the  temporals.  These  trans- 
mit the  effort  to  the  lateral  and  posterior  parts  of  the  body  of  the  sphe- 
noid, by  means  of  the  alae  majores  of  that  bone,  which  are  articulated,  along 
the  whole  extent  of  their  external  edge,  and  along  the  posterior  fourth  of 
their  internal  edge,  with  the  temporals.  Besides,  the  upper  extremity  of 
the  alae  majores  is  sloped,  on  the  inner  part  of  the  bone,  that  it  may  be  ar- 
ticulated with  the  anterior  and  inferior  angles  of  the  parietal  bones,  and 
answer  the  same  purpose  to  them  as  the  squamous  portion  of  the  tem- 
porals. 

The  lateral  and  posterior  parts  of  the  body  of  the  sphenoid  support, 
therefore,  almost  the  whole  effort  of  the  pressure  applied  to  the  parietal 
bones.  It  is  communicated  to  them  by  the  ate  majores,  which  receive 
it  themselves,  either  directly  at  the  anterior  and  inferior  angles  of  this 
bone,  or  through  the  medium  of  the  temporals.  The  small  portion  of 
the  effort  transmitted  by  the  latter  to  the  occipital,  follows  the  curved 
line  of  this  bone,  and  is  felt  on  the  posterior  face  of  the  body  of  the  sphe- 
noid. 

To  the  effort  resulting  from  the  pressure  exerted  by  the  body  on  the 
summit  of  the  head,  one  should  add  that  occasioned  by  the  contraction  of 
the  muscles  which  elevate  the  lower  jaw.  These  tend  to  depress  the  tem- 
poral, the  malar  and  the  sphenoid  bones,  and  in  this  action,  they  employ- 


•SL  power  equal  to  that  by  which  they  raise  the  lower  jaw,  and  press  it  firm- 
ly against  the  upper. 

The  effort  exerted  from  the  arch  to  the  base  of  the  skull  depends  there- 
fore, on  two  very  different  causes:  the  portion  resulting  from  the  action 
of  the  elevators  of  the  lower  jaw,  is  equal  to  the  effort  exerted  from  be- 
low upward,  by  this  bone.  After  what  has  been  stated,  it  would  be  use- 
less to  say  any  thing  further  of  the  manner  in  which  the  effort  is  trans- 
mitted :  we  may  merely  observe,  that  the  least  powerful  of  these  muscles, 
the  internal  pterygoid,  tends  to  draw  the  sphenoid  downward,  and  pre- 
vents this  bone,  fixed  like  a  wedge  with  its  base  turned  upward,  from 
being  disengaged  by  the  effort  applied  to  it,  by  the  bones  between  which 
it  is  situated. 

The  posterior,  anterior,  inferior  and  lateral  faces  of  the  sphenoid  bone, 
support,  therefore,  the  whole  effort  of  the  bones  of  the  skull  and  face,  on 
one  another,  when  the  top  of  the  head  being  loaded  with  a  heavy  burden, 
one  presses,  at  the  same  time,  something  very  firmly  between  the  dental 
arches. 

The  anterior  part  of  the  body  of  the  bone,  containing  the  sphenoidal 
sinus,  is  thin  and  very  frail ;  the  posterior  part,  corresponding  to  the  celia 
turcica,  is  alone  capable  of  resisting  the  effort  which,  I  believe,  it  is  des- 
tined to  sustain*:  hence,  it  is  at  this  point,  that  ossification  begins,  and 
this  confirms  the  observation  of  Kerkringius  that  the  spot  at  which  bones 
begin  to  ossify,  is  that  on  which  they  have  to  bear  the  greatest  effbrt; 
hence  the  alae  majores,  by  means  of  which  the  greatest  part  of  the  efforts 
which  the  body  of  the  sphenoid  has  to  support,  arise  from  the  lateral  part 
of  its  posterior  half,  by  an  origin  of  considerable  size,  and  which  is  fur- 
ther increased  by  the  base  of  the  pterygoid  processes  which  arise  from 
its  lower  part. 

I  have,  in  this  inquiry,  purposely  avoided  mentioning  the  support  which 
the  head  receives  from  the  vertebral  column,  and  which,  in  the  case  un- 
der consideration,  is  of  use  merely  in  preventing  it  from  yielding  to  the 
law  of  gravitation.  If  the  bones  of  the  skull  and  of  the  face  had  passed, 
during  the  effort  which  they  sustain,  on  the  circumference  of  the  fora- 
men magnum;  this  aperture  would  have  been  incapable  of  increasing  its 
dimensions,  and  this  would  have  been  attended  with  the  most  serious  in- 
conveniences. 

The  name  given  by  the  ancients  to  the  braje  whose  principal  use  has 
just  been  explained,  is  composed  of  spheno^which  means  a  wedge,  and 
eidos,  which  signifies  resemblance,  and  would  lead  one  to  think,  that  they 
were  not  ignorant  of  its  uses.  From  its  situation,  at  the  middle  and  in- 
ferior part  of  the  skull,  and  from  its  various  connexions  with  the  bones 
which  form  this  osseous  case,  it  is  to  them  of  the  same  use  as  the  key- 
stone of  arches,  with  regard  to  the  different  parts  of  which  they  are 
formed.  The  numerous  connexions  required  for  this  purpose,  account 


*  The  sphenoidal  sinus  is  prolonged,  it  is  true,  into  this  posterior  part  of  the  body  of 
the  bone,  in  persons  considerably  advanced  in  years;  but  the  parietes  of  this  portion  of 
its  cavity  are  of  considerable  thickness.  The  anterior  part  of  the  basilary  process  of 
the  occipital  bone,  is  ihen  firmly  united  to  the  sphenoid,  and  maybe  considered  as  form- 
ing  a  part  of  that  bone,  from  which  it  cannot  be  detached.  The  cranium  of  an  old  man, 
in  this  respect,  resembles  that  of  several  quadrupeds,  in  which  the  union  of  the  sphe- 
noid to  the  occipital  bone  takes  place  so  early,  thatthese  two  bones  might  well  be  con- 
sidered  as  forming  but  one. 


276 

for  its  strange  and  irregular  form  and  for  the  different  shapes  of  its  arti- 
cular surfaces  and  the  great  number  of  its  projections,  which  render  the 
demonstration  of  this  bone  so  complicated,  and  a  knowledge  of  it  so 
difficult. 

It  is  more  advantageous,  withregard  to  the  brain,  that  the  skull  should 
be  formed  of  several  bones,  than  if  it  had  consisted  of  a  single  bone.  It 
resists,  more  effectually,  the  blows  it  receives,  their  effect  being  lessened, 
in  passing  from  one  bone  to  the  other,  and  being  interrupted,  in  the  ob- 
scure motions  which  they  may  experience  at  their  sutures;  its  rounded 
form  increases,  likewise,  its  power  of  resistance.  This  force  would  be 
equal,  in  every  point  of  the  parietes  of  the  cranium,  if  the  form  of  that 
cavity  were  completely  spherical,  and  if  the  thickness  of  its  parietes  were, 
in  every  part  of  it,  the  same.  In  that  case,  no  fractures  by  contre  coup 
could  occur,  a  kind  of  lesson  occasioned  by  the  unequal  resistance  of  the 
bones  of  the  head,  to  the  force  applied  to  their  surface.  The  pericrani- 
um, the  hairy  scalp,  the  muscles  which  cover  it,  and  the  great  quantity  of 
hair  on  its  surface,  serve,  besides,  to  defend  the  brain,  and  are  well  cal- 
culated to  break  the  force  of  blows  applied  to  the  cranium. 

In  addition  to  this  hard  and  unyielding  case,  there  lies  over  the  brain, 
a  treble  membranous  covering,  formed  by  the  dura  mater,  which  owes 
its  names  to  the  erroneous  opinion  according  to  which  it  was  supposed  to 
form  all  the  other  membranes  of  the  body;  it  is  further  covered  by  the 
tunica  arachnoidea,  so  called  from  the  extreme  minuteness  of  its  tissue, 
and  by  the  pia  mater  which  adheres  firmly  to  the  substance  of  the  brain. 

The  dura  mater  lines,  not  only  the  inside  of  the  skull  and  of  the  verte- 
bral canal,  which  may  be  considered  as  a  prolongation  of  it,  but,  like- 
wise, penetrates  between  the  different  parts  of  the  cerebral  mass,  sup- 
ports them  in  the  different  positions  of  the  head,  and  prevents  mutual 
compression.  Thus,  the  greatest  of  its  folds,  the  falx,  stretched  between 
the  crista  galli  of  the  ethmoid  bone,  and  the  inner  protuberance  of  the 
occipital  bone,  prevents  the  two  hemispheres  of  the  brain,  between  which 
it  lies,  from  compressing  each  other,  when  the  body  is  on  the  side,  and 
maintains,  on  the  other  hand,  the  tentoriutn  cerebelli  in  the  state  of  ten- 
sion necessary  to  enable  it  to  support  the  weight  of  the  posterior  lobes  of 
the  brain.  This  fold  of  dura  mater  is  of  a  semi-circular  form,  separates  the 
portion  of  the  skull  which  contains  the  brain,  from  that  in  which  the  cere- 
bellum is  situated.  It  is  keot  in  a  state  of  tension  by  the  falx  cerebri,  on 
which  it  also  exerts  the  sjfce  action  :  it  does  not  present  a  horizontal 
plane  to  the  portion  of  brain  which  lies  upon  it,  but  one  that  slopes,  in 
every  direction,  towards  the  parietes  of  the  skull,  to  which  it  transmits 
most  of  the  weight  which  it  has  to  support.  The  tentorium  cerebelli, 
which  thus  divides  the  internal  cavity  of  the  skull  into  two  parts  of  unequal 
dimensions,  is  bony  in  some  animals  that  move  by  bounding  and  with 
rapid  action;  this  is  the  case  with  the  cat,  which  can,  without  being 
stunned,  take  leaps  from  a  considerable  height.  By  means  of  this  com- 
plete partition,  the  two  portions  of  the  brain  are  prevented  from  passing 
on  each  other,  in  the  violent  concussions  which  they  experience. 

The  tunica  arachnoides,  according  to  Bonn*,  who  was  thoroughly  ac- 
.quainted  with  its  structure,  and  who  has  given  a  very  beautiful  plate  of 
it,  is  the  secretory  organ  of  the  serum  which  moistens  the  internal  sur- 


Dissertatia  de  continuation} bits  msmbranartim.  Lug-dun.  4°  Bat.  1763. 


277 

face  of  the  dura  mater,  a  fibrous  membrane  which  serves  as  a  periosteum 
to  the  bones  it  lines*. 

CXLII1.  Of  the  size  of  the  brain.  Of  all  animals,  man  has  the  most 
capacious  skull,  in  proportion  to  his  face,  and,  as  the  bulk  of  the  brain 
is  always  of  a  size  t  proportioned  to  that  of  the  osseous  case  which  con- 
tains it,  the  brain  is  also  most  bulky  in  man.  This  difference  of  size  be- 
tween the  cranium  and  face,  may  be  taken  as  the  measure  of  the  human 
understanding  and  of  the  instinct  of  the  lower  animals  ;  the  stupidity  and 
ferocity  of  the  latter  are  greater,  according  as  the  proportions  of  these 
two  parts  of  their  skull,  vary  from  those  of  the  human  head. 

To  express  this  difference  of  size,  Camper  imagined  a  vertical  line 
drawn  from  the  forehead  to  the  chin,  and  perpendicular  to  another  drawn 
in  the  direction  of  the  base  of  the  skull.  He  has  called  the  first  of  these 
lines  facia!,  the  second,  palatine  or  mental.  It  is  easy  to  understand,  that, 
as  the  projection  of  the  forehead  is  determined  by  the  size  of  the  skull, 
the  larger  it  is,  the  more  the  angle  at  which  the  facial  line  meets  that 
from  the  base  of  the  skull  must  be  obtuse.  In  a  well-formed  European 
head,  the  facial  line  meets  the  palatine  at  an  angle  nearly  straight,  (of 
between  eighty  and  ninety  degrees.)  When  the  angle  is  quite  straight, 
and  the  line  which  measures  the  height  of  the  face  is  completely  vertical, 
the  head  is  of  the  most  beautiful  form  possible,  it  approaches  most  to 
that  conventional  degree  of  perfection  which  is  termed  ideal  beauty.  If 
the  facial  line  slopes  backward,  it  forms  with  the  palatine  line,  an  an- 
gle more  or  less  acute,  and  projecting  forward,  the  inclination  increases, 
and  the  sinus  of  the  angle  is  shorter;  if,  from  man,  we  pass  to  monkeys, 
then  to  quadrupeds,  to  birds,  reptiles,  and  fishes,  we  find  this  line  slope 
more  and  more,  and,  at  last,  become  almost  parallel  to  the  mental,  as  in 
reptiles  and  in  fishes,  with  flat  heads.  If,  on  the  contrary,  we  ascend 
from  man  to  the  gods,  whose  images  have  been  transmitted  to  us  by  the 
ancients,  we  find  the  facial  line  to  incline  in  a  different  direction,  the  an- 
gle then  enlarges  and  becomes  more  or  less  obtuse.  From  this  inclina- 
tion forward  of  the  facial  line,  there  results  an  air  of  grandeur  and  ma- 
jesty, a  projecting  forehead,  indicating  a  voluminous  brain  and  a  divine 
intellect}. 

To  obtain  with  precision,  by  this  means,  the  respective  dimensions  of 
the  skull  and  face,  one  must  measure,  not  only  the  outside,  but,  likewise, 
draw  the  tangents  on  the  internal  surfaces,  after  dividing  the  head  verti- 
cally. There  are,  in  fact,  animals,  in  which  the  sinuses  of  the  frontal 
bone  are  so  large,  that  a  considerable  portion  of  the  parietes  of  the 


*  Analagous  to  the  serous  membranes  which  line  the  cavities  of  the  body,  the  arach- 
noid is  a  shut  sac,  whose  internal  surface  is  every  where  in  contact  with  itself,  while  its 
external  surface  adheres  to  the  two  other  meninges.  The  serosity  which  exudes  from 
the  internal  surface  of  the  arachnoid  differs  from  that  which  escapes  from  the  other 
serous  membranes,  owing  to  the  almost  entire  absence  of  albumen  from  the  former. 
The  exhalation  that  takes  place  from  this  membrane  appears  to  be  the  source  of  a  more 
limpid  and  dilute  effusion,  even  in  disease,  than  that  which  is  observed  in  the  other 
serous  cavities. —  Copland. 

•J-  This  should  be  ruialin'ed.  In  many  animals  the  cavity  of  the  skull  is  small,  while 
the  osseous  case  appears  large ;  this  great  extent  of  bone  is  for  the  origin  of  the  power- 
ful muscles  necessary  to  the  seizing  and  comminution  of  their  food. — Godman. 

$  It  should  not  be  forgotten,  that  this  is  true  only  when  the  tbcial  angle  does  not  much 
exceed  90P.  Foreheads  projecting  more  than  this,  are  most  frequently  those  of  idiots 
or  hydrocephalic  persons. — Godman. 


278 

skull  is  protruded  by  their  cells.  Thus,  in  the  dog,  in  the  elephant, 
in  the  owl,  Sec.  the  apparent  size  of  the  skull  exceeds  much  its  real 
capacity*. 

The  relative  size  of  the  head,  and  consequently  the  proportionate  bulk 
of  the  brain,  is  inconsiderable  in  very  tall  and  muscular  subjects  :  this  fact 
will  be  confirmed  by  observing1  the  proportions  of  antique  statues.  In  all 
those  which  represent  heroes  or  athlets  gifted  with  a  prodigious  bodily- 
power,  the  head  is  very  small,  in  proportion  to  the  rest  of  the  body.  In 
the  statues  of  Hercules,  the  head  scarcely  equals  in  size  the  top  of  the 
shoulder.  The  statues  alone  of  the  King  of  the  Gods,  present  the  singu- 
lar combination  of  an  enormous  head,  resting  on  limbs  of  a  proportionate 
size,  but  the  Greek  artists  have  transgressed  the  laws  of  Nature,  only  in 
favour  of  the  God  that  rules  over  her,  as  if  a  vast  brain  had  been  neces- 
sary to  one  whose  intellect  carries  him,  at  a  glance,  over  the  universe. 
The  relative  small  dimensions  of  the  head,  in  athlets,  depend  on  this  cir- 
cumstance, that  in  such  men,  the  excessive  developement  of  the  organs 
of  motion,  gives  to  the  body,  and  especially  to  the  limbs,  an  enormous 
size,  while  the  head  covered  by  few  muscles,  remains  very  small.  Scem- 
mering  has  stated,  that  the  head  in  women  is  larger  than  in  men,  and 
that  their  brain  is  heavier;  but  it  must  be  recollected,  that  this  great 
anatomist  obtained  this  result,  by  examining  two  bodies,  male  and  fe- 
male, of  the  same  length.  Now,  the  absolute  size  being  the  same,  the 
proportionate  magnitude  was  not  so,  and  he  was  wrong  in  comparing  the 
head,  the  skull,  and  brain  of  a  very  tall  woman,  to  that  of  a  very  short 
man. 

It  has  long  been  thought,  that  there  exists  a  connexion  between  the 
bulk  of  the  cerebral  mass  and  the  energy  of  the  intellectual  faculties.  It 
has  been  thought,  that,  in  general,  men  whose  minds  are  most  capacious, 
whose  genius  is  most  capable  of  bold  conceptions,  have  a  large  head  sup- 
ported on  a  short  neck.  The  exceptions  to  this  general  rule  have  been 
so  numerous,  that  many  have  doubted  its  truth;  should  it  then  be  abso- 
lutely rejected,  and  will  it  be  allowed  to  be  wholly  without  foundation, 
when  we  consider  that  man,  the  only  rational  being  out  of  so  great  a 
number,  and  some  of  which  bear  to  him  a  considerable  resemblance  both 
of  organization  and  structure,  is,  likewise  the  only  animal  in  which  the 
brain,  properly  so  called,  is  largest  in  proportion  to  the  cerebellum,  to  the 
spinal  marrow,  to  the  nerves,  and  to  the  other  parts  of  the  body  ?  Why- 
may  it  not  be  with  the  brain,  as  with  the  other  organs,  which  fulfil  their 
functions  the  better,  from  being  more  completely  developed  ?  It  should 
be  recollected,  in  this  comparison  of  the  brain  and  of  the  intellectual  pow- 
ers, that  several  causes  may  give  to  this  viscus  an  unnatural  degree  of 
enlargement.  Thus,  in  subjects  of  aleucophlegmatic  temperament,  the 
tardy  ossification  of  the  bones  of  the  skull,  causes  the  brain,  gorged  with 
aqueous  fluids,  to  acquire  a  considerable  size,  without  its  containing  a 
greater  quantity  of  real  medullary  substance.  Hence  it  is  observed,  that 
men  of  this  temperament  are,  most  frequently,  unfit  for  mental  exertion, 
and  rarely  succeed  in  undertakings  that  require  activity  and  perse- 
verancef. 


*  Se  APPENDIX,  Note  D  D. 

f  See,  in  the  article  on  Temperaments,  an  account  of  the  influence  of  the  physical 
organization  on  the  moral  disposition  and  on  the  intellectual  faculties. 


CXLIV.  Structure  of  the  cerebral  mass.  What  we  know  of  the  brain, 
serves  only  to  show  us  that  we  are  ignorant  of  much  more.  All  that  we 
know  of  it  consists  of  notions  tolerably  exact  of  its  external  conformation, 
its  colour,  its  density,  and  of  the  different  substances  that  enter  into  its 
composition;  but  the  knowledge  of  its  intimate  structure  is  yet  a  rays-- 
tery,  which  will  not  be  so  soon  unveiled  to  us.  The  brain,  properly  so  call- 
ed, is  divided  by  a  longitudinal  furrow,  into  two  lobes  of  equal  bulk  — 
Gunzius,  however,  imagined  that  he  found  the  right  lobe,  or  hemisphere, 
a  little  larger  than  the  left;  but  even  were  this  fact  as  certain  as  it  is 
doubtful,  we  could  not  thereby  explain  the  predominant  force  of  the  right 
side  of  the  body,  since  the  nerves  which  are  distributed  to  this  side,  rise 
from  the  left  lobe  of  the  brain,  in  the  substance  of  which  all  the  roots  of 
these  cords  cross.  This  fact  of  the  crossing  of  the  nerves,  at  their  origin, 
is  proved  by  a  number  of  pathalogical  observations,  in  which  the  injury 
of  a  lobe  is  always  found  to  bring  on  paralysis,  convulsion,  or  any  other 
symptomatic  affection,  on  the  opposite  side  of  the  body.  Unless  you 
choose  to  explain  this  phenomena  by  admitting  a  necessary  equilibrium 
in  the  action  of  the  two  lobes;  an  equilibrium,  the  disturbance  of  which 
is  the  the  occasion  that  the  sound  lobe,  acting  with  more  force,  com- 
presses the  origin  of  the  nerves  on  its  side,  and  determines  paralysis. — 
Might  the%want  of  judgment,  the  unevenness  of  humour  and  character, 
depend  on  the  want  of  harmony  between  the  two  corresponding  halves  of 
the  cerebral  mass  ? 

In  order  to  disclose,  better  than  had  been  before  done,  the  structure  of 
the  brain,  M.  Gall  begins  his  dissection  at  the  lower  part,  examining,  in 
the  first  place,  the  anterior  part  of  the  prolongation,  known  under  the 
name  of  the  cauda  of  the  medulla  oblongata,  he  finds  the  two  pyramidical 
eminences.  If  you  part  the  two  edges  of  the  median  line,  below  the  fur- 
row which  separates  the  two  pyramids,  you  see  distinctly  the  crossing  of 
three  or  four  cords  or  fasciculi  of  nerves,  which,  consisting  of  many  fila- 
ments, tend  obliquely  from  right  to  left,  and  vice  versa*'.  This  crossing 
of  nervous  fibres,  which  is  not  found  in  any  other  part  of  the  brain,  had 
been  observed  by  several  anatomists.  It  is  not  known  how  it  came  to  be 
forgotten,  so  that  the  mobt  exact  and  latest  among  them,  Boyer,  for  in- 
stance, says  that  the  crossing  of  the  nerves  cannot  lie  proved  by  anatomy. 
These  nervous  cords,  traced  upward,  enlarge,  strengthen,  and  forming 
pyramidical  eminences,  ascend  towards  the  tuber  annulare.  Having 
reached  the  ganglion,  the  fibres  strike  into  it,  and  are  lost  in  a  mass  of 
pulpy  or  greyish  substance,  of  the  same  nature  as  that,  which,  under  the 
the  name  of  cortical  substance,  covers  the  two  lobes  of  the  brain.  This 
greyish  pulp,  distributed  in  various  parts,  may  be  considered,  agreeably 
to  the  views  of  M.  Gall,  who  calls  it  the  matrix  of  the  nerves,  as  the 
source  from  which  the  medullary  fibres  take  their  origin.  These  ascend- 
ing fibres  cross  other  transverse  fibres,  which,  on  either  side,  proceed 
from  the  crura  of  the  cerebellum  ;  enlarged  and  multiplied  by  means  of 
their  passage  through  the  grey  substance  which  is  found  in  the  tuber  an- 
nulare; they  rise  from  it,  at  its  upper  part,  in  two  fasciculi  which  cdfib 

*  While  dissecting  the  brain,  in  1823,  after  the  manner  described  by  J)r.  Gall,  lob- 
served  a  beautiful  and  well  marked  semicircle  of  fibres,  descending1  from  the  upper  part 
of  the  corpora  olivaria,  on  their  outside,  and  after  nearly  reaching-  their  inferior  points, 
rising  and  being  continued  over  the  surface  of  the  corpora  pyramidalia,  until  it  reached 
the  edge  of  the  tuber  annulare. — Godman, 


pose  nearly  the  whole  of  the  crura  cerebri.  The  interior  of  these  crura, 
contains  a  certain  quantity  of  grey  substance,  which  is  what  nourishes 
the  nervous  fibre*.  On  reaching  the  ventricles,  these  peduncles,  or  rather 
the  two  fasciculi  which  form  them,  meet  with  large  ganglions,  full  of 
grey  substance ;  these  have  long  been  called  thalami  optici,  though  they 
do  not  give  origin  to  the  optic  nerves.  There  the  fibres  are  sensibly  en- 
larged :  and  they  pass  from  the  thalami  optici  into  new  ganglions. 
These  are  the  corpora  striata,  and  the  striae  which  are  apparent  on  cut- 
ting these  pyriform  masses  of  grey  substance,  are  only  the  same  fibres, 
which,  enlarged,  multiplied,  and  radiated,  spread  out  in  the  manner  of 
a  fan,  towards  the  lobes  of  the  brain,  where,  after  forming  by  their  ex- 
pansion, a  whitish  and  fibrous  substance,  they  terminate  at  the  outer 
part  of  that  viscus,  forming  its  convolutions,  all  covered  with  the  sub- 
stance in  which  are  terminated,  in  like  manner,  the  extremities  of  the 
diverging  fibres.  From  this  grey  substance,  proceed  converging  fibres 
tending  from  all  parts  of  the  periphery  to  the  centre  of  the  brain,  where 
they  unite  to  form  the  different  commissures,  the  corpus  callosum,  and 
other  productions,  destined  to  facilitate  the  communication  of  the  two 
hemispheres!. 

The  exterior  of  the  brain  may,  therefore,  be  considered  as  a  vast  ner- 
vous membrane,  formed  by  the  grey  substance.  To  form  a  clue  concep- 
tion of  its  extent,  it  must  be  understood,  that  the  convolutions  of  the 
brain,  are  a  sort  of  duplicatures,  susceptible  of  extension  by  the  unfold- 
ing of  two  contiguous  medullary  lamina,  which  form  its  base.  The  exte- 
rior surface  of  the  brain,  by  means  of  this  unfolding,  offers  them  some 
relation  to  the  skin,  a  vast  nervous  expanse  every  where  covered  by  a 
sort  of  pulpy  substance,  known  by  the  name  of  the  rete  mucosum  of 
Malphigi.  M.  Gall  compares  this  cutaneous  pulp,  to  the  cineritious  sub- 
stance which  forms  the  outer  part  of  the  brain,  and,  I  must  confess,  it  is 
not  every  one  that  will  admit  the  analogy.  However,  true  it  is,  that  the 
brain  consists,  principally,  of  a  mass  of  ganglions,  that  it  produces  nei- 
ther the  elongated  medulla,  nor  the  spinal  marrow,  that  this  last  may  be 
considered  as  a  series  of  ganglions,  united  together  that  the  vertebral  nerves 
arise  from  the  greyish  pulp  of  which  the  spinal  marrow  is  full,  as  is  best 
seen  in  animals  without  a  brain,  but  not  the  less  provided  with  a  spinal 
marrow,  or  series  of  ganglions,  from  which  the  nerves  arise.  The  gan- 
glions, or  rather  the  grey  substance  which  they  always  show,  produce 
the  nervous  fibres,  and  thicken  the  nervous  cords  that  pass  through 
them. 

That  is  the  only  use  that  can  be  assigned  to  these  parts  of  the  nervous 
system  ;  for,  if  they  were  meant  to  withdraw  from  the  dominion  of  the 
will,  the  parts  in  which  they  are  found,  why  do  not  the  ganglions  of  the 
vertebral  nerves  fulfil  the  same  function  ?  All  these  nerves  communicate 
by  the  reciprocal  anastamoses.  These  communications,  in  man,  are 
equivalent  to  a  real  continuity.  In  truth,  the  brain  acts  upon  the  nerves 
that  proceed  from  the  spinal  marrow,  is  if  this  were  one  of  its  produc- 
4|ns,  and  all  the  nervous  fibres,  spread  through  the  different  organs,  had 
an  extremity  terminating  in  this  viscus. 

*  This  means  simply  that  the  cineritious  substance  is  found  where  the  fibrous  matter 
is  increased,  or  ganglia  are  formed.  As  to  its  nourishing  the  fibrous  structure,  it  is  a 
mere  assumption,  or  begging  the  question.-*-  Godman. 

f  See  APPENDIX,  Note  D  D.  ^ 


. 

281 

One  thing  well  worthy  of  attention,  and  on  which  no  anatomist  has 
dwelt,  is  that  the  brain  of  the  foetus,  and  of  the  child  just  born,  appears 
to  consist  almost  entirely,  of  a  cineritious  pulp,  to  such  a  degree  that  the 
medullary  substance  is  difficult  to  perceive  in  it.  Would  it  be  absurd  to 
believe,  that  the  medullary  part  of  the  brain  does  not  take  its  perfect  or- 
ganization till  after  birth,  by  the  developement  of  the  fasciculi  of  medul- 
lary fibres,  in  the  midst  of  these  masses  of  cineritious  substance,  which 
must  be  considered  as  the  common  source  from  which  the  nerves  have 
their  origin,  or,  to  use  the  language  of  Gall,  as  the  uterus  which  gives 
them  birth.  The  almost  total  inactivity,  the  passive  state  of  the  brain, 
in  the  foetus,  makes  unnecessary  there  the  existence  of  the  medullary  ap- 
paratus, to  which  the  most  important  operations  of  intelligence  seem  en- 
trusted. Its  first  rudiments  are  found  in  the  foetus  at  its  full  time.  That 
fibro  medullary  apparatus  will  be  strengthened  by  the  exercise  of  thought, 
as  the  muscles  are  seen  to  enlarge  and  perfect  their  growth,  by  the  effect 
of  muscular  action. 

CXLV.  Circulation  of  the  brain.  I  have  said  that  the  blood,  in  its 
circular  course,  does  not  traverse  the  different  parts  of  the  body  with  uni- 
form velocity;  that  there  are  partial  circulations  in  the  midst  of  the  ge- 
neral circulation.  In  no  organ  are  the  laws,  to  which  this  function  is 
subjected,  more  remarkably  modified  than  in  the  brain.  There  is  none 
which  receives,  in  proportion  to  its  bulk,  larger  arteries  and  more  in  num- 
ber. The  internal  carotid  and  vertebral  arteries,  as  we  may  satisfy  our- 
selves from  the  calculations  ot  tialler,  carry  thither  a  great  portion  of  the 
whole  quantity  of  blood  that  flows  along  the  aorta ;  (from  a  third  to  the 
half.) 

The  blood  which  goes  to  the  brain,  said  Boerhaave,  is  more  aerated 
than  that  which  is  distributed  to  the  other  parts  :  the  observation  is  not 
without  foundation.  Though  the  blood  which  the  contractions  of  the  left 
ventricle  send  Into  the  vessels,  arising  from  the  arch  of  the  aorta,  does 
not  undergo,  at  the  place  of  this  curvature,  a  mechanical  separation  car- 
rying its  lighter  parts  towards  the  head;  it  is  not  less  true,  that  this 
blood,  just  passing  from  the  contact  of  the  air  in  the  lungs,  possesses, 
in  the  highest  degree,  all  the  peculiar  qualities  of  arterial  blood.  So 
great  a  quantity  of  light,  red,  frothy  blood,  impregnated  with  caloric 
and  oxygen,  coming  upon  the  brain,  with  all  the  force  it  has  received 
from  the  action  of  the  heart,  would  unavoidably  have  deranged  its  soft 
and  delicate  structure,  if  nature  had  not  multiplied  precautions  to  weak- 
en its  impulse. 

The  fluid  compelled  to  ascend  against  its  own  weight,  loses,  from  that 
alone,  a  part  of  its  motion.  The  vertical  column  must  strike  against  the 
angular  curvature  which  the  internal  carotid  takes  in  its  passage  along 
the  osseous  canal  of  the  petrous  portion  of  the  temporal  bone,  and  as  this 
curvature,  supported  by  hard  parts,  cannot  straighten  itself,  the  column 
of  blood  is  violently  broken  and  turned  out  of  its  first  direction,  with  con- 
siderable loss  of  velocity. 

The  artery  immersed  in  the  blood  of  the  cavernous  sinus,  as  it  comes 
out  from  the  carotid  canal,  is  very  easily  dilated.  Finally,  the  branches 
into  which  it  parts,  on  reaching  the  base  of  the  brain,  have  coats  exceed- 
ingly thin,  and  so  weak  that  they  collapse,  when  they  are  empty,  like 
those  of  the  veins.  This  weakness  of  the  cerebral  arteries,  explains  their 
frequent  ruptures,  when  the  heart  sends  the  blood  into  them  too  violent- 
ly ;  and  it  is  thus,  that  the  most  part  of  sanguineous  apoplexies  are  oc- 


282 

casioned,  many  of  which,  however,  take  effect  without  rupture,  and  by 
the  mere  transudation  of  blood  through  the  coats  of  the  arteries.  These 
vessels,  like  the  branches  arising  from  their  divisions,  are  lodged  in  the 
depressions  with  which  the  base  of  the  brain  is  furrowed,  and  do  not  en- 
ter its  substance,  till  they  are  reduced  to  a  state  of  extreme  tenuity,  by 
the  further  divisions  they  undergo,  in  the  tissue  of  the  pia  mater. 

Notwithstanding  the  proximity  of  the  brain  to  the  heart,  the  blood 
reaches  it,  then,  with  an  exceedingly  slackened  motion :  it  returns,  on 
the  contrary,  with  a  motion  progressively  accelerated.  The  position  of 
the  veins  at  the  upper  part  of  the  brain,  between  its  convex  surface  and 
the  hollow  of  the  skull,  causes  these  vessels,  gently  compressed  by  the 
alternate  motions  of  rising  and  falling  of  the  cerebral  mass,  to  disgorge 
their  contents  readily  into  the  membranous  reservoirs  of  the  dura  mater, 
known  by  the  name  of  sinuses  These,  all  communicating  together,  of- 
fer to  this  fluid  a  sufficiently  large  receptacle,  from  which  it  passes  into 
the  great  jugular  vein,  which  is  to  carry  it  again  into  the  general  course 
of  the  circulation.  Not  only  is  the  calibre  of  this  vein  considerable,  but 
its  coats  too,  of  little  thickness,  are  extensible  :  so  much  so,  that  it  ac- 
quires by  injection,  a  calibre  superior  to  that  of  the  venae  cava.  The 
flowing  of  the  blood  is  favoured  by  its  own  weight,  which  makes  a  retro- 
grade course  very  difficult*. — Thus,  to  sum  up  all  that  is  peculiar  in  the 
cerebral  circulation,  the  brain  receives,  in  great  quantity,  a  blood  abound- 
ing in  oxygen  ;  the  fluid  finds,  in  its  course  thither,  many  obstacles  which 
impede  and  slacken  its  impulse,  whilst  all  uu  the  cuntrary,  favours  its  re- 
turn, and  prevents  venous  congestion!.  Let  me  observe,  to  conclude 
what  I  have  to  say  on  the  circulation  of  the  brain,  that  of  the  eye  is  near- 
ly allied  to  it,  since  the  ophthalmic  artery  is  given  out  by  the  internal  ca- 
rotid, and  the  ophthalmic  vein  empties  itself  into  the  cavernous  sinus  of 
the  dura  mater.  Accordingly,  the  redness  of  the  conjunctiva,  the  promi- 
nence, the  brightness,  the  moistness  of  the  eyes,  indicate  a  stronger  de- 
termination of  the  blood  towards  the  brain.  Thus  the  eyes  are  animat- 
ed at  the  approach  of  apoplexy,  in  the  transport  of  a  burning  fever,  du- 
ring delirium,  a  dangerous  symptom  of  malignant  or  ataxic  fevers.  On 
this  connexion  of  the  vessels  of  the  eye  and  brain,  depends  the  lividity  of 
the  conjunctiva,  whose  veins,  injected  with  a  dark  coloured  blood,  indi- 
cate the  fullness  of  the  brain  in  the  generality  of  cases  of  suffocation. 

CXLVI.  Of  the  connexion  betiueen  the  action  of  the  brain  and  that  of  tlie 
heart.  It  is  possible,  as  was  done  by  Galen,  to  tie  both  carotids,  in  a  liv- 
ing animal,  without  his  appearing  sensibly  affected  by  it  ;  but  if,  as  has 
never  yet  been  done,  both  the  vertebral  arteries  are  tied,  the  animal  drops 
instantly  and  dies,  at  the  end  of  a  few  seconds.  To  perform  this  experi- 
ment, it  is  necessary,  after  tying  the  carotid  arteries  of  a  dog,  to  remove 
the  soft  parts  which  cover  the  side  of  the  neck,  then  with  needles,  bent  in 
a  semi-circular  form,  passed  into  the  flesh  along  the  sides  of  the  articu- 
lation of  the  cervical  vertebrae,  to  apply  ligatures  to  the  arteries  which 


*  In  preventing  this  reflux,  there  is  no  use  of  valves,  which  the  jugular  vein  is  entire- 
ly without.  It  is  sufficiently  prevented,  hy  the  direction  in  which  the  blood  Hows,  and 
the  extensibility  of  its  coats.  This  great  size  which  the  vein  can  acquire,  would  have 
made  useless  the  valvular  folds,  insufficient  to  stop  the  canal,  in  that  great  augmenta- 
tion of  its  dimensions. — Author's  Note. 

t  The  transverse  anastomoses  of  the  arteries,  at  the  base  of  the  brain,  are  very  prop- 
er for  distributing  the  blood,  in  equal  quantity,  to  all  parts  of  this  viscus, —  Copland 


283 

ascend  along  their  transverse  processes.  The  same  effect,  viz.  the  speedy 
death  of  the  animal  is  produced  by  tying  the  ascending  aorta  in  an  herbi- 
vorous quadruped. 

These  experiments,  which  have  been  repeated  a  number  of  times,  de- 
cidedly prove  the  necessity  of  the  action  of  the  heart  on  the  brain,  in  pre- 
serving life.  But  how  does  this  action  operate  ?  Is  it  merely  mechanical? 
Does  it  consist  solely  in  the  gentle  pressure  which  the  arteries  of  the 
brain  exert  on  the  substance  oif  this  viscus,  or  is  it  merely,  to  the  inter- 
cepted arterial  blood  which  the  contractions  of  the  heart  determine  to- 
wards the  brain,  that  death  is  to  be  attributed  ?  The  latter  opinion  seems 
to  me  the  most  probable,  for,  if,  the  moment  the  vertebrals  have  been 
tied,  the  carotids  are  laid  open,  and  the  pipe  of  a  syringe  adapted  to  them, 
and  any  fluid  whatever  is  then  injected  with  a  moderate  degree  of  force, 
and  at  nearlv  the  s*ame  intervals  as  those  of  the  circulation,  the  animal 
will  not  be  restored  to  life. 

The  heart  and  brain  are,  therefore,  united  to  each  other  by  the  strict- 
est connexion,  the  continual  access  of  the  blood  flowing  along  the  ar- 
teries of  the  head,  is,  therefore,  absolutely  necessary  to  the  preserva- 
tion of  life  ;  if  intercepted,  for  one  moment,  the  animal  is  infallibly  de- 
stroyed. 

The  energy  of  the  brain  appears,  in  general,  to  bear  a  relation  to  the 
quantity  of  arterial  blood  which  it  receives.  I  know  a  literary  man,  who, 
in  the  ardour  of  composition,  exhibits  all  the  symptoms  of  a  kind  of  brain 
fever.  His  face  becomes  red  and  animated,  his  eyes  sparkling ;  the  ca- 
rotids pulsate  violently  ;  the  jugular  veins  are  swollen,  every  thing  indi- 
cates that  the  blood  is  carried  to  the  brain  with  an  impetus,  and  in  a 
quantity  proportioned  to  its  degree  of  excitement.  It  is,  indeed,  only  du- 
ring this  kind  of  erection  of  the  cerebral  organ,  that  his  ideas  flow  with- 
out effort,  and  that  his  fruitful  imagination  traces,  at  pleasure,  the  most 
beautiful  descriptions.  Nothing  is  so  favourable  to  this  condition  as  re- 
maining long  in  a  recumbent  posture  :  in  this  horizontal  posture,  the  de- 
termination of  the  fluids  towards  the  head  is  the  more  easy,  as  the  limbs, 
which  are  perfectly  quiescent,  do  not  divert  its  course.  He  can  bring  on 
this  state  by  fixing  his  attention  steadfastly  on  one  object.  May  not  the 
brain,  which  is  the  seat  of  the  intellectual  action,  be  considered  as  a  cen- 
tre of  fluxion ;  and  may  not  the  stimulus  of  the  mind  be  compared,  as  to 
its  effects,  to  any  other  stimulus,  chemical  or  mechanical*  ? 

A  young  man  of  a  sanguineous  temperament,  subject  to  inflammatory  fe- 
vers which  always  terminate  by  a  profuse  bleeding  at  the  nose,  experien- 
ces, during  the  febrile  paroxysms,  a  remarkable  increase  of  his  intellec- 
tual powers  and  of  the  activity  of  his  imagination.  Authors  had  already 
observed,  that  in  certain  febrile  affections,  patients  of  very  ordinary  pow- 
ers of  mind,  would  sometimes  rise  to  ideas,  which  in  a  state  of  health, 
would  have  exceeded  the  limits  of  their  conception.  May  we  not  ad- 
duce these  facts  in  opposition  to  the  theory  of  a  celebrated  physician, 

• 


*  The  inequality  of  the  distribution  of  the  blood,  attributable  to  the  peculiar  action 
of  food  &c.  on  the  stomach  and  nerves,  immediately  connected  with  the  great  vessels 
going  to  the  brain,  is  peculiarly  worthy  of  the  attention  of  physiologists  and  pathologists. 
In  a  paper,  published  in  the  3d  volume  of  the  Philadelphia  Journal,  an  attempt  is  mad6 
"to  show  the  relation  of  nerves  producing1  some  of  the  most  remarkable  sympathetic 
connexions. — Godmav . 


, 

who  considers  a  diminution  of  the  energy  of  the  brain  to  be  the  essential 
character  of  fever  ? 

It  is  well  known  that  the  difference  of  the  length  of  the  neck,  and,  con- 
sequently, the  greater  or  lesser  degree  of  vicinity  of  the  heart  and  brain, 
give  a  tolerable  just  measure  of  the  intellect  of  man,  and  of  the  instinct  of 
the  lower  animals  ;  the  disproportionate  length  of  the  neck  has  ever  been 
considered  as  the  emblem  of  stupidity. 

In  the  actual  state  of  our  knowledge,  is  it  possible  to  determine  in  what 
manner  arterial  blood  acts  on  the  brain  ?  Are  oxygen  or  caloric,  of  which 
it  is  the  vehicle,  separated  from  it  by|this  viscus,  so  as  to  become  the  prin- 
ciple of  sensation  and  emotion,  or  do  they  merely  preserve  it  in  the  de- 
gree of  consistence  necessary  to  the  exercise  of  its  functions  ?  What  is  to 
be  thought  of  the  opinion  of  those  chemists  who  consider  the  brain,  as  a 
mere  albuminous  mass,  concreted  by  oxygen,  and  of  a  consistence  vary- 
ing in  different  persons,  according  to  the  age,  the  sex,  or  the  state  of 
health  or  disease  ?  Any  answer  that  one  might  give  to  these  premature 
questions,  would  be  but  a  simple  conjecture  to  which  it  would  be  diffi- 
cult to  give  any  degree  of  probability*. 

CXLVII.  Of  the  theory  of  syncope.  If  we  consider  the  action  of  the 
heart  on  the  brain,  we  are  naturally  led  to  admit  its  necessity  to  the  main- 
tenance of  life,  and  to  deduce  from  its  momentary  suspension,  the  theo- 
ry of  syncope.  Several  authors  have  attempted  to  explain  the  manner  in 
which  their  proximate  cause  operates,  but  as  not  one  of  them  has  gone 
upon  facts  ascertained  by  experience,  their  explanations  do  not  at  all 
agree  with  what  is  learnt  from  observing  the  phenomena  of  these  dis- 
eases. 

To  satisfy  one's  self,  that  the  momentary  cessation  of  the  action  of  the 
heart  and  the  brain,  is  the  immediate  cause  of  syncope,  one  need  but 
read,  with  attention,  the  chapter  which  Cullen,  in  his  work  on  the  prac- 


*  The  connexion  which  exists  between  the  functions  of  the  heart  and  those  of  the 
brain,  are  not  only  manifest  in  their  healthy  relations,  but  also  in  their  disordered  ac- 
tions. PORTAL,  BRICHETEAU  and  TESTA  had  pointed  out  this  connexion  in  the  diseases 
of  these  organs,  and  more  recently  Dr.  CRAISIE  has  contended  for  its  importance,  al- 
though some  contemporary  puthologists  have  denied  its  existence.  This  pathologist, 
after  stating  his  experience  on  the  subject,  draws  the  following  inferences  from  it : — 

"  1st.  It  is  quite  obvious,  that  several  maladies  of  the  heart,  such  as  ossification  of  the 
left  side,  or  of  the  artery  connected  with  it ;  ossification  of  the  mitral  valve  ;  of  the  semi- 
lunar  valves  ;  ossification  of  the  apertures  either  auriculo-ventricular,  or  aortic,  have  a 
tendency  to  terminate  in  extravasation  within  the  cranium,  producing  apoplexy,  paraly- 
sis, or  a  comatose  state  terminating  in  death. 

"2d.  It  is  by  no  means  difficult  to  see  how  these  effects  in  the  cerebral  organ  result 
from  an  irregular  and  disordered  action  of  the  heart.  The  difficulty  which  the  blood 
experiences  in  passing  either,  1st.  through  the  auriculo-ventricular  opening ;  2d.  the 
aortic  orifice  ;  3d.  along  the  aorta,  necessarily  produces  a  stagnation  and  congestion ; 
1st.  in  the  pulmonary  veins ;  2d.  in  the  pulmonary  artery  ;  3d.  in  the  right  side  of  the 
heart.  The  effect  of  this  is  to  retardpr  impede  very  remarkably  the  return  of  the  blood 
from  the  cerebral  veins,  and  consecutively  either  to  distend  them,  to  rupture  them,  or 
to  occasion  an  effusion  of  the  serous  part  of  the  blood,  as  we  find  in  other  examples  of 
obsti-ucted  venous  circulation." — (Edin.  Med.  Journ.  JYo.  74.) — Dr.  Craigie  has,  how- 
ever, omitted  to  mention  the  influence  of  active  enlargement  of  the  left  side  of  the 
heart  in  causing  apoplexy,  owing  to  the  increased  impulse  or  determination  of  blood 
which  is  thus  produced,  and  to  which  the  brain  is  most  obnoxious.  This  and  every  oth- 
er form  of  connexion  of  disease  of  the  heart  with  apoplexy  can  only  be  viewed  as  occa- 
sional occurrences,  the  former  states  being  by  no  means  necessarily  followed  by  the  lat- 
ter. —  Copland. 


285 

tice  of  physic,  has  devoted  to  the  consideration  of  this  kind  of  affection. 
It  will  be  readily  understood,  that  their  occasional  causes,  the  varieties 
of  which  determine  their  different-kinds,  exist  in  the  heart  or  great  blood-, 
vessels,  or  act  on  the  epigastric  centre,  and  affect  the  brain  only  in  a  se- 
condary manner.  Thus,  the  kinds  of  syncope  occasioned  by  aneurismal 
dilatations  of  the  hear*  and  great  vessels,  by  polypous  concretions  formed 
in  these  passages,  by  ossification  of  their  parietes  or  of  their  valves,  evi- 
dently depend  on  the  extreme  debility,  or  on  the  entire  cessation  of  the 
action  of  the  heart  and  arteries.  Their  parietes,  ossified,  dilated,  ad- 
hering to  the  neighbouring  parts,  or  compressed  by  any  fluid  whatever, 
no  longer  act  on  the  blood  with  sufficient  force,  or  else  this  fluid  is  in- 
terrupted in  its  progress  by  some  obstacle  within  its  canal,  as  a  polypous 
concretion,  an  ossified  and  immoveable  valve.  Cullen,  very  justly,  termed 
these,  idopathic  or  cardiac  syncopes. 

To  the  above  may  be  added  plethoric  syncope,  depending  on  a  con- 
gestion of  blood  in  the  cavities  of  the  heart:  the  contractions  of  this  or- 
gan become  more  frequent,  it  struggles  to  part  with  this  excess  of  blood, 
which  is  injurious  to  the  performance  of  its  functions:  but  to  this  un- 
usual excitement,  by  which  the  contractility  of  its  fibres  is  exhausted, 
there  succeeds  a  kind  of  paralysis  necessarily  accompanied  by  syncope. 

One  may,  likewise,  include  the  fainting  attending  copious  blood-let- 
ting ;  the  rapid  detraction  of  a  certain  quantity  of  the  vivifying  principle, 
deprives  the  heart  of  the  stimulus  necessary  to  keep  up  its  action.  The 
same  effect  is  produced  by  drawing  off  the  water  contained  in  the  abdo- 
men, in  ascites:  a  considerable  number  of  vessels  cea§e  to  be  compressed; 
the  blood,  which  they  before  refused  to  transmit,  is  sent  to  them  in  pro- 
fusion; the  quantity  sent  to  the  brain  by  the  heart  is  lessened,  in  the  same 
proportion,  and  becomes  insufficient  for  its  excitement.  Among  the  syn- 
copes, called  idiophatic,  one  may  enumerate  those  occurring  in  the  last 
stage  of  the  scurvy,  the  principal  character  of  which  is,  an  excessive  de- 
bility of  the  muscles  employed  in  the  vital  functions,  and  in  voluntary 
motion;  lastly,  we  may  add  asphyxia  from  strangulation,  from  drowning, 
and  from  the  gases  unfit  for  respiration  ;  affections  in  which  the  blood 
being  deprived  of  the  principle  which  enables  it  to  determine  the  con- 
tractions of  the  heart,  the  circulation  becomes  interrupted.  If  the  blood 
loses,  by  slow  degrees,  its  stimulating  qualities,  the  action  of  the  heart 
gradually  weakened,  impels  towards  the  brain  a  blood  which,  by  its 
qualities,  partakes  of  the  nature  of  venous  blood,  and  which,  like  it, 
cannot  preserve  the  natural  economy  of  the  brain.  It  was  thought,  that 
by  injecting  a  few  bubbles  of  air  into  the  jugular  vein  of  a  do.-,  one  might 
occasion  in  the  animal  immediate  syncope,  and  that  it  was  even  su.ncient 
to  deprive  it  of  life;  but  the  late  experiments  of  Nysten  have  proved, 
that  the  atmospherical  air  produces  these  bad  effects,  only  when  injected 
in  a  quantity  sufficient  to  distend,  in  excess,  the  cavities  of  the  heart,  or 
when  by  being  injected  into  the  arteries  it  compresses  the  brain.  When 
injected  only  in  a  small  quantity,  the  gas  dissolved  in  the  venous  blood, 
is  conveyed  along  with  it  to  the  lungs,  and  is  thence  exhaled  in  respira- 
tion. 

A  second  class  of  occasional  causes  consists  of  those  which,  by  acting 
on  the  epigastric  centre,  determine,  by  sympathy,  a  cessation  of  the  pulsa- 
tions of  the  heart  and  the  syncope  necessarily  attending  this  sensation. 
Such  are  the  violent  emotions  of  the  soul,  terror,  an  excess  of  joy,  an  ir- 
resistible aversion  to  certain  kinds  of  food,  the  dread  which  is  felt  on  the 


286 

unexpected  sight  of  an  object,  the  disagreeable  impression  occasioned 
by  certain  odours,  8cc.  In  all  these  cases,  there  is  felt,  in  the  region  of 
the  diaphragm,  an  inward  sensation  of  a  certain  degree  of  emotion.  From 
the  solar  plexus  of  the  great  sympathetic  nerve,  which,  according  to  the 
general  opinion,  is  considered  as  the  seat  of  this  sensation,  its  effects  ex- 
tend to  the  other  abdominal  and  thoracic  plexuses.  The  heart,  the  great- 
er part  of  whose  nerves  arise  from  the  great  sympathetic,  is  particularly 
affected  by  this  sensation.  Its  action  is,  at  times,  merely  disturbed  by  it, 
and  at  other  wholly  suspended.  The  pulse  becomes  insensible,  the  coun- 
tenance pale,  the  extremities  cold,  and  syncope  ensues.  This  is  the  course 
of  things,  when  a  narcotic  or  poisonous  substance  has  been  taken  into 
the  stomach;  when  this  viscus  is  much  debilitated,  in  consequence  of 
long  fasting,  or  when  it  contains  indigestible  substances;  in  colic,  and  in 
hysterical  affections. 

The  last  class  of  occasional  causes  do  not  act  directly,  and  produce 
syncope  only  at  a  distant  period;  but  the  result  is  always  the  same.  It 
happens,  in  all  the  cases,  that  as  the  arteries  of  the  head  no  longer  receive 
as  much  blood  as  in  health,  the  brain  falls  into  a  kind  of  collapse,  which 
occasions  a  momentary  cessation  of  the  intellectual  faculties,  of  the  vital 
functions,  and  of  voluntary  motion. 

Morgagni,  in  treating  of  diseases,  according  to  their  anatomical  order, 
ranks  lypothymia  among  the  affections  of  the  chest,  because  the  viscera 
contained  in  that  cavity,  show  marks  of  organic  affection,  in  persons  who, 
during  life,,  were  subject  to  frequent  fainting. 

The  compression  of  the  brain,  by  a  fluid  effused  on  the  dura  mater,  in 
\vounds  of  the  head,  does  not  produce  real  syncope,  but  rather  a  state  of 
stupor.  All  causes,  acting  in  this  manner  on  the  brain,  produce  coma- 
tose and  even  apoplectic  affections.  When  a  man,  on  being  exasperated, 
falls  into  a  violent  and  ^sudden  fit  of  passion,  his  face  becomes  flushed, 
and  he  is  affected  with  vertigo  and  fainting.  There  is  no  loss  of  colour, 
no  loss  of  pulse;  the  latter,  on  the  contrary,  generally  boats  with  more 
force.  This  is  not  syncope,  but  the  first  stage  of  apoplexy,  occasioned 
by  the  mechanical  pressure  on  the  brain,  towards  which  the  blood  is  car- 
ried suddenly  and  in  too  great  a  quantity. 

I  might  support  this  theory  of  syncope,  by  additional  proofs  drawn 
from  the  circumstances  which  favour  the  action  of  the  causes  giving  rise 
to  affections  of  this  kind.  For  instance,  syncope  comes  on,  almost  al- 
ways, when  we  are  in  an  erect  posture;  and  in  such  a  case,  it  is  right  to 
lay  the  patient  in  a  horizontal  posture.  Patients  debilitated  by  long  dis- 
eases, taint  the  moment  they  attempt  to  rise,  and  recover  on  returning 
to  the  recumbent  posture.  Now,  how  are  we  to  explain  this  effect  of 
standing,  in  persons  in  whom  the  mass  of  humours  is  much  impoverished, 
and  whose  organic  action  is  extremely  languid,  unless  by  the  greater  dif- 
ficulty to  the  return  of  the  blood,  from  the  more  depending  parts,  and  on 
the  difficulty  in  ascending,  of  that  which  the  contractions  of  the  heart 
send  towards  the  head  ?  The  phenomena  of  the  circulation,  are,  under 
such  circumstances,  more  subject  to  the  laws  of  hydraulics,  than  when 
the  body  is  in  a  state  of  health  ;  the  living  solid  yields  more  easily  to  the 
laws  of  physics  and  mechanics,  and,  according  to  the  sublime  idea  of  the 
father  of  physic,  our  individual  nature  approaches  the  more  to  universal 
nature. 

CXLVIII.  Of  the  motions  of  the  brain.  Are  the  alternate  motions  of 
elevation  and  depression  seen,  when  the  brain  is  exposed,  exclusively 


387 

isochronous  to  the  pulsations  of  the  heart  and  arteries,  or  do  they  cor- 
respond, at  the  same  time,  to  those  of  respiration  ?  Such  is  the  physio- 
logical problem,  of  which  I  am  about  to  attempt  the  solution. 

Those  authors  who  admit  the  existence  of  motions  in  the  dura  mater, 
do  not  agree  as  to  the  cause  which  produces  them.  Some,  and  among 
others,  Willis  and  Bagiivi,  thought  they  had  discovered  muscular  fibres, 
and  ascribed  these  motions  to  their  action:  others,  as  Fallopius  and  Bau- 
hinus,  attributed  these  motions  to  the  pulsations  of  the  arteries  of  that 
membrane.  The  dura  mater  possesses  no  contractile  power;  its  firm 
adhesion  to  the  inside  of  the  skull,  would,  besides,  prevent  any  such  mo- 
tion. The  motion  observed  in  this  membrane  is  not  occasioned  by  the 
action  of  its  vessels;  for,  as  Lorry  observes,  the  arteries  of  the  stomach, 
of  the  intestines,  and  of  the  bladder,  do  not  communicate  any  motion  to 
the  parietes  of  these  hollow  viscera;  and  yet,  in  number  and  size,  they 
at  least  equal  the  meningeal  arteries. 

The  motion  observed  in  the  dura  mater  is  communicated  to  it  by  the 
cerebral  mass  which  this  membrane  covers;  and  this  opinion  of  Galen, 
adopted  by  the  greater  number  of  anatomists,  has  been  placed  beyond  a 
doubt,  by  the  experiments  of  Schlitting,  of  Lamure,  Haller,  and  Vicq- 
d'Azyr.  They  have  all  observed,  that  on  removing  the  dura  mater,  the 
brain  continued  to  rise  and  fall;  and,  with  the  exception  of  Schlitting, 
they  agreed  that  the  brain,  absolutely  passive,  received  from  its  vessels 
the  motions  in  which  the  dura  mater  partook:  but  are  these  motions 
communicated  by  the  arteries  or  by  the  cerebral  veins,  and  by  the  sinuses 
in  which  these  terminate;  or,  in  other  words,  are  they  isochronous  to 
the  beats  of  the  pulse,  or  to  the  contraction  and  successive  dilatation  of 
the  chest,  during  respiration. 

Galen,  in  his  treatise  on  this  function,  says,  that  the  air  admitted  into 
the  pulmonary  organ  distends  the  diaphragm,  and  is  conveyed  along  the 
vertebral  canal  into  the  skull.  According  to  this  writer,  the  brain  rises 
during  the  enlargement  of  the  chest;  and  it  sinks,  on  the  contrary,  when 
the  parietes  of  this  cavity  are  brought  nearer  to  its  axis.  Schlitting,  in 
a  memoir  presented  to  the  Academy  of  Sciences,  towards  the  middle  of 
the  last  century,  maintains  that  these  motions  take  place,  in  a  different 
order;  the  elevation  of  the  brain  corresponding  to  expiration,  and  its  de- 
pression to  inspiration.  Conceiving  that  he  has  determined  this  fact  by 
a  sufficient  number  of  experiments,  he  does  not  enter  into  any  explana- 
tion; and  concludes  his  inquiry,  by  asking  whether  the  motions  of  the 
brain  are  occasioned  by  the  afflux  of  air,  or  of  blood,  towards  that  organ. 

Haller  and  Lamure  attempted  to  answer  this  difficulty.  They  both 
performed  a  number  of  experiments  on  living  animals,  acknowledged 
the  fact  observed  by  Schlitting,  and  explained  it  in  the  following  man- 
ner: as  well  as  this  last  anatomist,  Lamure  believed  that  there  is  a  va- 
cuum between  the  dura  and  pia  mater;  by  means  of  which,  the  motions 
of  the  brain  might  always  be  performed.  The  existence  of  such  vacuum 
is  disproved,  by  the  close  contact  of  the  membranes  between  which  it  is 
supposed  to  exist. 

During  expiration,  continues  Lamure,  the  parietes  of  the  chest  close 
on  themselves,  and  lessen  the  extent  of  this  cavity.  The  lungs,  pressed 
in  every  direction,  collapse;  the  curvature  of  their  vessels  increases,  and 
the  blood  flows  along  them  with  difficulty.  The  heart  and  great  vessels 
thus  compressed,  the  blood  carried  off  by  the  upper  vena  cava  to  the 
right  auricle,  cannot  be  freely  poured  into  this  cavity  which  empties 


288 

itself,  with  difficulty,  into  the  right  ventricle,  whose  blood  is  unable  to 
penetrate  through  the  pulmonary  tissue.  On  the  other  hand,  as  the  lungs 
compress  the  vena  cava,  a  regurgitation  takes  place  of  the  blood  which 
it  was  conveying  to  the  heart;  forced  back  along  the  jugulars  and  verte- 
brals,  it  distends  these  vessels,  the  sinus  of  the  dura  mater  which  empty 
themselves  into  them,  and  the  veins  of  the  brain  which  terminate  in 
these  sinuses.  Their  distension  accounts  for  the  elevation  of  the  cerebral 
mass  soon  followed  by  depression,  when,  on  inspiration  succeeding  expi- 
ration, and  on  the  lungs  dilating,  the  blood  which  fills  the  right  cavities 
of  the  heart  can  freely  penetrate  into  the  pulmonary  substance,  and  make 
way  for  that  which  the  vena  cava  is  bringing  from  the  superior  parts  of 
the  body. 

Haller  considered  this  reflux  as  very  difficult,  the  blood  having  to  rise 
against  its  own  gravity;  and  he  admitted  Lamure's  explanation  only  in 
the  forcible  acts  of  respiration,  as  in  coughing,  laughing,  and  sneezing. 
He  maintained  that,  in  a  state  of  health,  there  is  to  be  observed,  during 
expiration,  a  mere  stagnation  of  the  blood,  in  the  vessels  which  bring  it 
from  the  internal  parts  of  the  skull.  He  further  admits,  on  the  testimony 
of  a  great  number  of  authors,  another  order  of  motions  depending  on 
the  pulsations  of  its  arteries;  so  that,  according  to  Haller,  the  cerebral 
mass  is  incessantly  affected  by  motions,  some  of  which  depend  on  respi- 
ration, while  others  are  quite  independent  of  it. 

Lastly,  according  to  Vicq-d'Azyr,  the  brain,  on  being  exposed,  pre- 
sents a  double  motion,  or  rather,  two  kinds  of  motion,  from  without;  the 
one  from  the  arteries,  and,  which  is  least  remarkable,  the  other  from  the 
alternate  motions  of  respiration. 

CXLIX.  This  opposition  between  authors  of  reputation,  and  whose 
theories  have,  in  general,  been  adopted,  induced  me  to  repeat  the  experi- 
ments which  each  of  them  brings  in  support  of  his  own  opinion,  and  to 
perform  further  experiments  on  this  subject.  My  investigation  soon  con- 
vinced me,  that  these  authors  had  given  a  statement  of  their  opinions,  and 
not  of  the  fact  itself.  In  fact,  the  alternate  motions  of  elevation  and 
depression  observed  in  the  brain,  are  isochronous  to  the  systole  and  dia- 
stole of  the  arteries  at  its  base.  The  elevation  of  the  brain  corresponds 
to  the  dilatation  of  these  vessels,  its  depression  to  their  contractions. 
The  process  of  respiration  has  nothing  to  do  with  this  phenomenon,  and 
even  admitting  the  stagnation  of  the  regurgitation  of  the  blood  in  the 
jugular  veins,  the  arrangement  of  the  veins,  within  the  skull,  is  such,  that 
this  stagnation  or  reflux  could  not  produce  alternate  motions  of  the  cere- 
bral mass. 

The  brain  receives  its  arteries  from  the  carotids  and  vertebrals,  after 
they  have  entered  the  skull,  the  former  along  the  carotid  canals,  the  lat- 
ter through  the  foramen  magnum  of  the  occipital  bone.  It  would  be  use- 
less to  describe  their  numerous  divisions,  their  frequent  anastomoses,  the 
arterial  circle,  or  rather  polygon  formed  by  these  anastomoses,  and  by 
means  of  Avhich  the  carotid  and  vertebral  arteries  communicate  together, 
by  the  side  of  the  sella  turcica.  Haller  has  given  a  very  correct  view  and 
an  excellent  description  of  this  part*.  The  account  of  the  internal  caro- 
tid artery  published  by  that  great  anatomist  is,  according  to  Vicq-d'Azyr, 
a  chief-d'oeuvre  of  learning  and  precision  ;  the  same  encomium  might  be 


Fasciculi  Anatomici,  F.  7,  tab.  2, 


289 

bestowed  on  the  latter  who  gave  a  superb  dra\ving  of  the  same  part.  I 
shall  content  myself  with  observing,  that  the  principal  arterial  trunks 
going  to  the  brain,  are  situated  at  the  base  of  this  viscus ;  that  the 
branches  into  which  these  trunks  divide,  and  the  subdivisions  of  these 
branches,  are,  likewise,  lodged  at  its  base  in  a  number  of  depressions, 
and  that,  in  the  last  place,  the  arteries  of  the  brain  do  not  penetrate  into 
its  substance,  after  they  have  undergone  in  the  tissue  of  the  pia  mater, 
which  appear,  completely  vascular,  very  minute  subdivisi  -ns. 

The  vessels  which  return  the  portion  of  blood  which  has  not  been 
employed  in  the  nutrition  and  growth  of  the  brain,  are  on  the  contrary, 
situated  towards  its  upper  part,  between  its  convex  surface,  and  the  arch 
of  the  cranium,  each  convolution  contains  a  great  vein  which  opens  into 
the  superior  longitudinal  sinus.  The  vena  Galeni  which  deposits  into  the 
sinus,  the  blood  brought  from  the  choroid  plexus;  small  veins  which 
open  into  the  cavernous  sinuses;  others,  likewise  very  minute,  which 
passing  through  the  foramina  in  the  alse  majores  of  the  sphenoid  bone, 
contribute  to  form  the  venous  plexus  of  the  zygomatic  fossa,  are  the  only 
exceptions  to  this  general  rule. 

This  being  laid  down  in  the  arrangement  of  the  arteries  and  veins,  let 
us  examine  what  will  be  the  effect  of  their  action,  with  regard  to  this 
viacus. 

The  contractions  of  the  heart  propel  the  blood  into  the  arterial  tubes, 
which  experience  especially  at  the  place  of  their  curvatures,  a  manifest 
displacement,  at  the  time  of  their  dilatation.  All  the  arteries  situated 
at  the  base  of  the  brain,  experience  both  these  effects  at  once.  Their 
united  efforts,  communicate  to  it  a  motion  of  elevation  succeeded  by  de- 
pression, when  by  their  contraction,  they  re-act  on  the  blood  which  fills 
them. 

These  motions  take  place,  only  as  long  as  the  skull  remains  entire;  this 
cavity  is  too  accurately  filled,  and  there  is  no  void  space  between  the 
membranes  of  the  brain.  Lorry  who,  with  good  reason,  denied  the  ex- 
istence of  s«ch  a  space,  committed  an  equally  serious  anatomical  mis- 
take in  asserting,  that  as  no  motion  could  take  place,  on  account  of  the 
state  of  fulness  of  the  skull,  it  was  effected  in  the  ventricles,  which  he 
considers  as  real  cavities,  but  which,  as  Haller  has  shown,  are,  when  in  a 
natural  state,  merely  surfaces  in  contact.  No  motion  actually  takes  place, 
except  in  those  cases  in  which  there  is  a  loss  of  substance  in  the  parietes 
of  the  skull. 

It  is  easy  to  conceive,  however,  that  the  brain  which  is  soft  and  of  weak 
consistence,  yields  to  the  gentle  pressure  of  ics  arterial  vessels.  Does 
not  this  continued  action  of  the  heart  on  the  brain,  explain  in  a  satisfactory 
manner,  the  remarkable  sympathy  between  those  two  organs,  linked  by 
such  close  connections  ?  It  is,  besides,  of  very  manliest  utility,  and  con- 
nected with  the  return  of  the  blood  distributed  to  the  cerebral  mass  and 
to  its  envelopes.  The  veins  which  bring  it  back,  alternately  compressed 
against  the  arch  of  the  skull,  empty  themselves  more  easily  into  the 
sinuses  of  the  dura  mater,  towards  which  their  course  is  retrograde,  and 
unfavourable  to  the  circulation  of  the  blood  which  they  pour  into  them. 

When  any  thing  impedes  the  free  passage  of  the  blood  through  the 
lungs,  it  stagnates  in  the  right  cavities  of  the  heart;  the  superior  vena 
cava,  the  internal  jugulars,  and  consequently  the  sinuses  of  the  dura 
mater,  and  the  veins  of  the  brain  which  terminate  in  them,  are  gradual- 
ly distended ;  and  if  this  dilatation  were  carried  to  a  certain  degree,  the 

2O 


veins  of  the  brain,  placed  between  it  and  the  arch  of  the  skull,  would  tend 
to  depress  it  towards  the  base  of  that  cavity.  If  this  dilatation,  at  first 
sight,  were  carried  beyond  the  extensibility  of  these  vessels,  their  rup- 
ture would  occasion  fatal  effusions.  It  is  in  this  manner,  that  some 
authors  have  explained  sanguineous  apoplexy. 

It  will  be  objected,  perhaps,  that  many  of  the  sinuses  of  the  dura  mater 
are  at  the  base  of  the  skull,  and  that,  consequently,  their  dilatation  must 
tend  to  raise  the  cerebral  mass. 

But  the  greater  part  of  these  sinuses  are  connected  only  with  the  cere- 
bellum and  the  medulla  oblongata,  of  which  it  has  not  yet  been  possible 
to  ascertain  the  motions.  These  sinuses  are  almost  all  lodged  in  the  edges 
of  the  falx  and  of  the  teutorium  cerebelli.  The  cavernous  sinus  in  which 
the  ophthalmic  vein  disgorges  itself,  the  communicating  sinuses,  which 
allow  the  blood  of  one  of  these  sinuses  to  pass  into  the  other,  are  two  in- 
significant to  produce  a  raising  of  the  cerebral  mass.  Lastly,  the  resist- 
ance of  their  parietes,  formed  chiefly  by  the  dura  mater,  must  set  strait 
bounds  to  their  dilatation  ;  the  spongy  tissue  which  fills  the  interior  of 
the  cavernous  sinuses,  still  makes  this  dilatation  and  the  reflux  of  the 
blood  more  difficult, 

CL.  It  is  enough  to  prove,  by  reasons  drawn  frorn^  the  disposition  of 
parts,  that  the  motions  of  the  brain  are  communidfcted  to  it,  by  the  col- 
lection of  arteries  at  its  base;  the  fact  must  yet  be  established  upon  ob- 
servation, and  placed  beyond  doubt,  by  positive  experiments.  The  fol- 
lowing are  what  I  have  attempted  for  this  purpose  : 

A.  I  have  first  repeated   the  observation  of  some  authors,  and  ascer- 
tained, as  they  did,  that  the  pulsations  felt  on  placing  the  finger  on  the 
fontanels  of  the  skulls  of  new-born   infants,  correspond  perfectly  to  the 
beatings  of  the  heart  and  arteries. 

B.  A  patient,  trepanned  for  fracture,  with  effusion  on  the  dura  mater, 
enabled  me  to  see  the  brain,  alternately  rising  and  falling.     The  rising 
corresponded  with  the  diastole,  the  falling  with  the  systole  of  the  arte- 
ries. 

C.  Two  dogs,  trepanned,   exhibited  the  same  phenomenon,  in  the 
same  relation,  to  the  dilatation  and  contraction  of  the  arteries. 

D.  I  removed,  carefully,  the  arch  of  the  skull,  on  the  body  of  an  adult. 
The  dura  mater,  disengaged  from  its  adhesions  to  the  bones  which  it 
lines  was  preserved,  perfectly  untouched.  I  afterwards  laid  bare  the  main 
carotids,  and  injected  them  with  water.     At  every  stroke  of  the  piston, 
the  brain  showed  a  very  sensible  motion  of  rising,  especially  when  the 
injection  was  forced  at  once  along  the  two  carotids. 

E.  I  have  injected  the  internal  jugular  veins.     The  cerebral  mass  re- 
mained motionless.     Only  the  veins  of  the  brain,  the  sinuses  of  the  dura 
mater  dilated.     The  injection  having  been  kept  up  for  some  time,  there 
resulted  from  it  a  slight  swelling  of  the  brain  :  when  driven  with  more 
force,  some  of  the  veins  burst,  and  the  liquor  flowed  out.     The  same  in- 
jection being  made  with  water  strongly  reddened,   the  surface  of  the 
brain  became  coloured  with  an  intense  red.     To  see  clearly  this  effect, 
you  ought,  after  removing  the  arch  of  the  skull,  to  divide,  on  each  side, 
the  dura  mater,  on  a  level  with  the  circular  incision  of  the  skull,  then 
turn  back  the  flaps  towards  the  upper  longitudinal  sinus. 

F.  The  internal  jugular  veins  having  been  laid  open,  while  the  injec- 
tion was  forced  along  the  main  carotids,  each  time  the  piston  was  pushed 
forward,  the  venous  blood  flowed  with  the  greatest  impetus  j  a  clear  proof 


£91 

.of  the  manifest  influence  of  the  motions  of  the  brain,  on  the  course  of 
the  blood  in  its  veins,  and  in  thesinuses  of  the  dura  mater.  This  experi- 
ment had  been  already  performed  by  other  anatomists,  and  amongst 
others,  byRuysch,  with  a  view  of  proving  the  immediate  communication 
between  the  arteries  and  veins.  This  communication,  which  is,  at  pre- 
sent, universally  acknowledged,  may  be  proved  by  other  facts.  This  one 
is  evidently  any  thing  but  conclusive. 

G.  In  a  trepanned  dog,  I  tied  successively  the  two  carotids.  The 
motions  of  the  brain  abated,  but  did  not  cease.  The  anastomoses  of  the 
vertebrals,  with  the  branches  of  the. carotids,  account  for  this  pheno- 
menon. 

H.  I  took  a  rabbit,  a  gentle  creature,  easy  to  confine,  and  very  well 
adapted  for  difficult  experiments :  after  laying  bare  the  brain,  and  ob- 
serving that  its  motions  were  simultaneous  to  the  beats  of  the  heart,  I 
tied  the  trunk  of  the  ascending  aorta  :  the  moment  the  blood  ceased  ris- 
ing to  the  head,  the  brain  ceased  moving,  and  the  animal  died. 

I.  The  tying  of  the  internal  jugular  veins,  did  not  stop  the  motions  of 
the  brain  ;  but  its  veins  dilated,  and  its  surface,  bared  by  the  removal  of 
the  flap  of  the  dura  mater,  was  sensibly  redder  than  in  the  natural  state.— 
The  dog  became  affected  with  stupor,  and  expired  in  convulsions. 

The  opening  of  these  veins  did  not  hinder  the  continuance  of  the  mo- 
tions 5  they  grew  fainter  only  when  the  animal  was  weakened  by  loss  of 
blood. 

K.  The  opening  of  the  superior  longitudinal  sinus,  the  only  one  that 
could  easily  be  opened,  did  not  weaken  the  motions  of  the  brain.  It  is 
observed  that  the  blood  flows  out  more  freely  from  it,  during  the  eleva- 
tion. 

D.  The  compression  of  the  thorax,  on  human  bodies,  produces  but 
a  slight  reflux  in  the  jugular  veins,  especially,  if,  during  this  compres- 
sion, the  trunk  is  kept  raised.  The  reflux  is  greater,  when  the  trunk  is 
laid  flat. 

These  experiments  might  be  varied  and  multiplied ;  if,  for  instance, 
the  injection  were  thrown,  at  once,  along  the  vertebral  arteries,  and  the 
internal  carotids  ;  but  those  I  have  stated  are  sufficient  for  my  purpose. 

Since  the  first  publication  of  this  inquiry,  in  the  Memoirs  of  the  Me- 
dical Society,*  I  have  had  many  opportunities  of  repeating  the  observa- 
tions and  experiments,  which  serve  as  a  foundation  to  the  theory  there 
detailed.  Among  the  facts  which  confirm  this  theory,  there  is  one  that 
appears  to  me  worth  stating:  it  would  be  sufficient  by  itself,  if  it  were 
possible  to  establish  a  theory  on  the  observation  of  a  single  fact.  A 
woman,  about  fifty  years  of  age,  had  an  extensive  carious  affection  of  the 
skull;  the  left  parietal  bone  was  destroyed,  in  the  greatest  part  of  its  ex- 
tent, and  left  uncovered  a  very  considerable  portion  of  the  dura  mater. 
Nothing  was  easier  than  to  ascertain  the  existence  of  a  complete  corres- 
pondence, between  the  motions  of  the  brain  and  the  beats  of  the  pulse. 
I  desired  the  patient  to  cough,  to  suspend  her  respiration  suddenly,  the 
motions  continued  in  the  same  relation  to  ea^n  other;  when  she  coughed, 
the  head  was  shaken,  and  the  general  concussion,  in  which  the  brain  par- 


*  Memoirs  de  la  Societe  Medicale  dc Paris,  an  VII.  (1799.)  troisieme  anne,  page  197J 
ct  suiv. 


292 

took,  might  have  been  mistaken  by  a  prejudiced  observer,  for  the  proper 
motions  of  that  organ,  and  depending  on  the  reflux  of  blood  in  the  veins* 

In  experiments  on  dogs,  the  same  motion  takes  place,  when  the  animal 
barks,  but  it  is  easy  to  perceive,  that  the  concussion  affecting  the  brain  is 
experienced  by  the  whole  body,  and  that  the  effort  of  expiration,  in  bark- 
ing, causes  a  concussion  more  or  less  violent. 

The  patient,  mentioned  in  the  preceding  observation,  died  about  a 
month  after  I  came  to  the  Hospital  of  St.  Louis,  in  which  she  had  been 
for  a  considerable  length  of  time.  On  opening  the  body,  the  left  lobe  of 
the  brain  was  found  softened  and  in  a  kind  of  putrid  state;  the  ichor  which 
ivas  formed,  in  considerable  quantity,  flowed  outwardly,  by  a  fistulous 
opening  in  the  dura  ir.ater  whose  tissue  was  rather  thickened. 

CLI.  The  slight  consistence  of  the  brain,  which  Lorry  considers  as 
favourable  to  the  communication  of  the  motion  which  its  arteries  impart 
to  it,  appears  to  me  to  be  against  this  transmission.  In  fact,  the  dilated 
vessels  not  being  able  to  depress  the  base  of  the  skull  on  which  they  rest, 
make  their  effort  against  the  cerebral  mass,  and  raise  it  the  more  easily 
(the  arch  of  the  skull  being  removed)  from  its  presenting  a  certain  re- 
sistance. If  the  brain  were  too  soft,  the  artery  would  merely  swell  into 
it,  and  would  not  lift  it.  To  satisfy  one's  self  of  this  truth,  one  need  only 
observe  what  happens  when  the  posterior  part  of  the  knee  rests  on  a  pil- 
low, or  on  any  thing  of  the  same  sort;  then,  the  motions  which  the  pop- 
liteal artery  impresses  on  the  limb,  are  but  little  apparent ;  but  they  be- 
come very  visible,  if  the  ham  rests  on  any  thing  that  resists  the  action  on 
the  other  knee,  for  in  stance :— -  then  the  artery  which  cannot  depress  it, 
exerts  its  whole  action  in  raising  the  lower  extremity:  which  it  does,  the 
more  easily,  from  acting  against  a  bony,  resisting,  and  hard  part.  This 
experiment  completely  invalidates  the  opinion  of  Lorry.  The  want  of 
analogy  will  not  be  objected  ;  it  will  not  be  said  that  the  brain  is  heavier 
than  the  lower  extremity,  nor  that  the  sum  of  the  calibres  of  the  internal 
carotid  and  the  vertebral  arteries,  is  not  greater  than  that  of  the  popliteal 
artery. 

This  continual  tendency  of  the  brain  to  rise,  produces  in  the  end,  on 
the  bones  of  the  skull  which  resist  this  motion,  very  marked  effects. 
Thus,  the  interior  surface  of  these  bones,  smooth,  in  early  life,  becomes 
furrowed  with  depressions,  the  deeper  as  we  advance  in  aqe.  The  digi- 
tal depressions  and  the  mammillary  processss,  corresponding  to  the  con- 
volutions and  windings  of  the  brain,  are  very  evidently  the  result  of  its 
action  on  the  enclosing  parietes.  Sometimes  it  happens,  that,  at  a  very 
advanced  age,  the  bones  of  the  skull  are  so  thinned  by  this  internal  ac- 
tion, that  the  pulsations  of  the  brain  become  perceptible  through  the 
hairy  scalp. 

No  doubt,  the  same  cause  hastens  the  destruction  of  the  skull  by  the 
fungous  tumours  of  the  dura  mater.  The  effort  from  expansion  of  the 
tumour,  which  develops  itself,  is  further  added,  and  makes  the  waste  of 
the  bones  more  rapid.  At  the  end  of  a  few  months,  the  tumour  projects 
outwardly,  with  pulsations  plainly  simultaneous  to  the  beadnga  of  the 
pulse,  as  Louis  observes  in  a  Memoir  inserted  among  those  of  the  Aca- 
demy of  Surgery. 

1  have  shown  (CXLIX.)  that  the  opposition  of  the  veins  of  the  brain 
and  of  the  sinuses  of  the  dura  mater  w<xs  adverse  to  the  action  ascribed 
to  them,  on  this  viscus.  Experiment  (E.  L.)  shows  that  the  stagnation 


293 

of  the  blood,  or  even  its  regurgitation,  could  produce  only  a  slow  and 
gradual  distension  of  the  sinuses  of  the  dura  mater,  and  veins  terminating 
in  it,  with  a  slight  turgescence  of  the  cerebral  mass,  if  the  cause,  pro- 
ducing the  stagnation  of  the  blood  or  its  reflux,  prolonged  its  action  to  a 
partial  destruction  of  the  skull. 

Lastly,  the  alternate  motions  of  the  brain,  said  to  correspond  to  those 
of  respiration,  ought  to  be  the  beats  of  the  pulse,  in  the  ordinary  ratio  of 
1  to  5.  On  the  contrary,  it  is  easy  to  satisfy  one's  self  that  these  mo- 
tions are  in  an  inverse  ratio,  and  perfectly  simultaneous  to  the  pulsations 
of  the  heart  and  arteries. 

Theresults  of  the  experiments  I  have  stated  in  that  Memoir,  compared 
to  those  obtained  by  justly  celebrated  inquirers,  are  too  remarkably  dif- 
ferent not  to  have  induced  me  to  make  some  attempt  at  investigating  the 
cause  of  our  disagreement.  For  that  purpose,  I  thought  it  necessary  to 
examine  scrupulously  all  the  circumstances. 

The  work  of  Lamure  contains  anatomical  errors,  which  throw  suspi- 
cions upon  his  accuracy.  Haller  did  not  himself  make  the  experiments 
of  which  he  speaks,  in  treating  of  the  influence  of  respiration  on  the  cir- 
culation of  venous  blood.  This  article  is  drawn  from  a  thesis  defended 
at  Gottingen  by  one  of  his  disciples.  Lastly,  Vicq-d'Azyr  attempted  no 
confirming  experiment,  and  seems  to  have  had  in  view  only  the  reconcil- 
ing all  opinions. 

No  one  of  those  anatomists  has  distinguished  the  motions  of  elevation 
impressed  on  the  cerebral  mass  by  the  influence  of  its  arteries,  from  the 
swelling  of  the  sinuses  of  the  dura  mater,  of  the  veins  distributed  to  it, 
and  from  the  tumefaction  of  the  brain  which  may  be  caused  by  difficult 
respiration.  This  mistake  would  be  the  more  easy,  as  animals  tortured 
by  the  knife  of  the  anatomist,  breathe  painfully,  convulsively,  and  at 
shorter  intervals  than  in  their  natural  state.  Schlitting,  the  first  author 
of  these  experiments,  appears  especially  to  have  confounded  the  motion 
of  rising,  the  real  displacement  of  the  brain,  with  the  turgescence  of  this 
viscus.  At  every  expiration,  he  says,  I  have  seen  ths  brain  rise,  that  is 
to  say,  swell,  and  at  every  inspiration  I  have  seen  it  fall,  that  is  to  say, 
collapse. 

"Toties  animadverti  persfiicue — in  omni  exfiiralione,  cerebrum  univer sum 
ascendere,  id  est  intumescere  ;  atque  in  quavis  inspiratione  iliud  descendere,  id 
est  detumescere." 

We  may,  therefore,  consider  as  a  truth  strictly  demonstrated  by  obser- 
vation, experiment,  and  reasoning,  the  following  proposition  : — 

The  motions  observable  in  the  brain,  when  laid  bare,  are  imparted  to  it  solely 
by  the  pulsations  of  the  arteries  at  its  base,  and  are  perfectly  simultaneous  to 
the  fiulsations  of  these  vessels  :  further,  the  reflux  and  stagnation  of  the  venous 
blood*  are  able  to  swell  its  substance. 

CLII.  fiction  of  the  nerves  and  brain.  It  is  undoubtedly,  as  Vicq-d'Azyr 
has  said,  by  a  motion  of  some  sort  that  the  nerves  act.  '  Setting  out  from 
this  simple,  idea,  one  may  admit  several  kinds  of  nervous  motions,  the 
one  operating  from  the  circumference  to  the  centre,  it  is  the  motion  of 
sensation  which  we  are  about  more  particularly  to  study  in  this  para- 
graph ;  the  other,  acting  from  the  centre  to  the  circumference,  and  this 
motion,  produced  by  the  will,  determines  the  actitfn  of  the  muscular  or- 
gans, &c. 

In  what  manner  arc  the  impressions  produced  on  the  senses  by  the  bo- 
dies which  surround  us,  transmitted,  along  the  nerves  to  the  brain  ?  Is  it 


294 

through  the  intervention  of  a  very  subtle  fluid,  or  can  the  nerves,  as  has 
been  stated  by  some  physiologists,  be  considered  as  vibrating  cords  ?  This 
last  idea  is  so  absurd,  that  one  cannot  help  wondering  it  shduld  so  long 
have  been  in  vogue.  A  cord  that  it  must  vibrate,  must  be  in  a  state  of 
tension,  along  the  whole  of  its  length,  and  fixed  at  both  extremities*  The 
nerves  are  not  in  a  state  of  tension,  their  extremities,  in  no  degree  fixed, 
approach  towards  each  other,  or  recede  according  to  the  difference  of  po- 
sition, the  tension,  the  turgescence,  the  fullness  or  collapse  of  the  parts, 
and  vary  constantly  in  their  distance  from  each  other.  Besides,  the  ner- 
vous cords,  situated  between  pulps,  at  their  origin,  and  at  their  termina- 
tion, cannot  be  extended  between  these  two  points.  The  nervous  fibre  is 
the  softest,  the  least  elastic  of  all  the  animal  fibres  ;  when  a  nerve  is  divi- 
vided,  its  two  extremities,  far  from  receding  by  contracting,  project,  on 
the  contrary,  beyond  each  other  ;  the  point  of  sections  shows  a  number 
of  small  granulations  of  medullary  and  nervous  substance,  which  flows 
through  its  minute  membranous  canals.  Surrounded  by  parts  to  which 
they  are,  to  a  certain  degree,  united,  the  nerves  could  not  vibrate  ;  lastly, 
admittingthe  possibility  of  their  being  capable  of  vibrating-, the  vibration 
of  a  single  filament  ought  to  bring  on  that  of  all  the  rest,  and  carry  con- 
fusion and  disorder  in  every  motion  and  sensation. 

It  is  much  more  probable  that  the  nerves  act  by  means  of  subtle,  invi- 
sible, and  impalpable  fluid,  to  which  the  ancients  gave  the  name  of  ani- 
mal spirits:  this  fluid,  unknown  in  its  nature,  and  to  be  judged  of  only  by 
its  effects,  must  be  wonderfully  minute,  since  it  eludes  all  our  means  of 
investigation.  Does  it  entirely  proceed  from  the  brain,  or  is  it  equally 
secreted,  by  the  membranous  envelopes  of  each  nervous  filament?  (Neu- 
rilemes,  Reil.)  To  say  the  truth,  one  can  bring  no  other  proof  of  the  ex- 
istence of  a  nervous  fluid,  but  the  facility  with  which,  by  means  of  it,  we 
are  enabled  to  explain  the  various  phenomena  of  sensation,  and  its  utility  in 
explaining  these  phenomena.  These  proofs,  however,  may  not  appeal- 
completely  satisfactory  to  those  who  are  very  strict,  and  who  do  not  con- 
sider as  proved  what  is  merely  probable. 

Among  the  constituent  principles  of  the  atmosphere,  there  are  gene- 
rally diffused  several  fluids,  such  as  the  magnetic  and  electric  fluids. 
Might  not  these  fluids,  on  entering  with  the  air  into  the  lungs,  combine 
with  the  arterial  blood,  and  be  conveyed,  by  means  of  it,  to  the  brain,  or 
to  the  other  organs  ?  Does  not  the  vital  action  impart  to  them  new  qua- 
lities, by  making  them  undergo  unknown  combinations  ?  Do  caloric  and 
oxygen  enter  into  these  combinations  which  endow  fluids  with  a  certain 
vitality,  and  produce  on  them  important  changes,  and  which  are  not  un- 
derstood* ?  Have  not  these  conjectures  acquired  a  certain  degree  of 
probability,  since  the  analogy  of  galvanism  to  electricity,  at  first  suppos- 
ed by  the  author  of  this  discovery,  has  been  confirmed,  by  the  very  curi- 
ous experiments  of  Volta,  repeated,  commented,  and  explained,  by  all 
the  natural  philosophers  of  the  present  day,  in  Europet ! 

The  action  of  the  nervous  fluid  takes  place,  from  the  extremity  of  the 


*  Were  it  not  for  these  changes,  electricity,  magnetism,  and  galvanism,  would  suffice 
to  restore  life  to  an  animal  recently  dead. —  Copland. 

•J-  Galvanism,  as  yet,  has  not  realized  the  expectations  of  physiologists.  Chemistry 
has  derived  the  greatest  advantage  from  it.  It  is,  at  present,  with  M.  M.  Davy,  The- 
nard,  and  Gay-Lussac,  the  most  powerful  agent  in  the  analysis  of  certain  bodies. — Cop- 
land, 


295 

nerves  towards  the  brain,  so  as  to  produce  the  phenomena  of  sensation, 
for,  when  the  nerves  are  tied,  the  parts  below  the  ligature  lose  the  power 
of  sensation,  while,  as  will  be  seen  in  the  proper  place,  this  action  is  pro- 
pagated <rom  the  brain  towards  the  nervous  extremities,  and  from  the  cen- 
tre to  the  circumference,  in  producing  motions  of  every  kind.  This  dou- 
ble current,  in  contrary  directions,  may  take  place  in  the  same  nerves, 
and  it  is  not  necessary  to  arrange  the  nerves  into  two  classes  of  sensation 
and  of  motion. 

All  the  impressions  received  by  the  organs  of  sense,  and  by  the  senti- 
ent extremities  of  nerves,  are  transmitted  to  the  cerebral  mass.  The 
brain  is,  therefore,  the  centre  of  animal  life ;  all  sensations  are  carried  to 
it ;  it  is  the  spring  of  all  voluntary  motion  ;  this  centre  is  to  the  functions 
of  relation,  as  the  heart  to  the  functions  of  nutrition.  One  may  say  of 
the  brain,  as  of  the  heart,  omnibus  dat  et  ab  omnibus  accijiit.  It  receives 
from  all,  and  gives  to  all*. 

The  existence  of  a  centre,  to  which  all  the  sensations  are  carried,  and 
from  which  all  motions  spring,  is  necessary  to  the  unity  of  a  thinking 
being,  and  to  the  harmony  of  the  intellectual  functions.  But  is  this  seat 
of  the  principle  of  motion  and  of  sensation,  circumscribed  within  the  nar- 
row limits  oi'  a  mathematical  point,  or  rather  should  it  not  be  considered 
as  diffused  over  nearly  the  whole  brain  ?  The  latter  appears  to  me  the 
more  probable  opinion;  were  it  otherwise,  what  could  be  the  use  of  those 
divisions  of  the  organ  into  several  internal  cavities;  what  could  be  the 
use  of  those  prominences  all  varying  in  their  form;  and  of  the  arrange- 
ment of  the  two  substances  which  enter  into  their  structure  ?  We  may 
conjecture,  and  with  considerable  probability,  that  each  .perception,  each 
class  of  ideas,  each  faculty,  is  assigned  to  some  peculiar  part  of  the  brain. 
It  is,  indeed,  impossible  to  determine  the  peculiar  functions  of  each  part 
of  the  organ  ;  to  say  what  purpose  is  served  by  the  ventricles,  what  is  the 
use  of  the  commissures,  what  takes  place  in  the  peduncles  ;  but  it  is  im- 
possible to  study  an  arrangement  of  such  combination,  and  to  believe 
that  it  is  without  design,  and  that  this  division  of  the  cerebral  mass,  into 
so  many  parts,  so  distinct,  and  of  such  various  forms,  is  not  relative  to 
the  different  function,  which  each  has  to  fill  in  the  process  of  thought. 
That  ingenious  comparison,  mentioned  in  the  panegyric  of  Mery,  by 
Fontenelle,  is  very  applicable  to  the  brain.  "  We  anatomists,"  he  once 
said  to  me,  4i  are  like  the  porters  in  Paris,  who  are  acquainted  with  the 
narrowest  and  most  distant  streets,  but  who  know  nothing  of  what  takes 
place  in  the  houses."  What  then  are  we  to  think  of  the  system  of  Gall, 
and  of  his  division  of  the  outside  of  the  skull  into  several  compartments, 
•which,  according  to  the  depression  or  projection  of  the  osseous  case,  in- 
dicate the  absence  or  the  presence  of  certain  faculties,  moral  or  intellec- 
tual? I  cannot  help  thinking,  that  this  physiological  doctrine  of  the  func- 
tions of  the  brain,  resting  on  too  few  well  observed  facts,  is  frivolous;  while 
his  anatomical  discoveries  on  the  anatomy  of  this  organ,  and  on  the  ner- 
vous system,  are  of  the  highest  importance,  and  well  founded. 

CLIII.  Analysis  of  the  Understanding.  In  vain  were  the  organs  of 
sense  laid  open  to  all  impressions  of  surrounding  objects ;  in  vain  were 
their  nerves  fitted  for  their  transmission :  these  impressions  were  to  us  as 
if  they  had  never  been,  were  there  not  provided  a  seat  of  consciousness 
in  the  brain.  For  it  is  there,  that  every  sensation  is  felt ;  light  and  sound, 


*  See  APPENDIX,  Note  E  E, 


296 

and  odour,  and  taste,  are  not  felt  in  the  organs  they  impress ;  it  is  the 
sensitive  centre  that  sees,  and  hears,  and  smells,  and  tastes.  You  have 
only  to  interrupt,  by  compression  of  the  nerves,,  the  communication  be- 
tween the  organs  and  the  brain,  and  all  consciousness  of  the  impressions 
of  objects,  all  sensation  is  suspended. 

The  torturing  pains  of  a  whitlow  cease,  if  you  bind  the  arm  so  strongly 
as  to  compress  the  nerve  which  carries  the  sensation  to  the  brain.  A 
living  animal,  under  experiments,  suffers  nothing  from  the  most  cruel 
laceration,  if  you  have  first  cut  the  nerves  of  the  parts  on  which  you  are 
operating.  To  conclude,  the  organs  of  sense,  and  the  nerves  which  com- 
municate between  them  and  the  brain,  shall  have  suffered  no  injury, 
shall  be  in  perfect  state  for  receiving  and  transmitting  the  sensitive  im- 
pression, yet  no  phenomena  of  sensation  can  take  place,  if  the  brain  be 
deceased;  when  it  is  compressed,  for  instance,  by  a  collection  of  fluid,  or 
by  a  splinter  from  the  skull  in  a  wound  of  the  head.  This  organ  is, 
therefore,  the  immediate  instrument  of  sensations,  of  which  impressions 
made  on  the  others  are  only  the  occasional  causes.  This  modification  of 
sensibility,  which  serves  to  establish  the  relations  of  the  living  being,  with 
objects  without,  would  be  correctly  denominated  cerebral  sensibility;  but 
that  even  in  animals  without  brain,  or  distinct  nervous  system,  it  is  very 
manifest.  The  sensibility,  in  virtue  of  which  the  polypus  dilates  his  ca- 
vity, for  the  admission  of  his  prey,  and  contracts  itself  to  retain  it,  is  in 
fact,  quite  distinct  from  that  sensibility  of  nutrition,  by  which  its  substance 
is  enabled  to  take  to  itself  nutritious  juices. 

The  brain,  as  Cabanis  has  well  expressed  it,  acts  upon  the  impression 
transmitted  by  the  nerves,  as  the  stomach  upon  the  aliments  it  receives 
by  the  oesophagus  :  it  does,  in  its  own  way,  digest  them  :  set  in  motion  by 
the  impulse  it  receives,  it  begins  to  re-act;  and  that  re-action  isthe/zer- 
cefitive  sensation,  or  perception.  From  that  moment,  the  impression  be- 
comes an  idea,  it  enters  as  an  element  into  thought  5  and  becomes  sub- 
ject-to the  various  combinations  that  are  necessary  to  the  phenomena 
of  understanding*. 

CLIV.  Our  sensations  are  nothing  but  modifications  of  our  being;  they 
are  not  qualities  of  the  objects  :  no  body  has  colour  to  the  blind  from 
birth:  the  rose  has  lost  its  most  precious  quality  to  him  who  has  lost  his 
smell :  he  knows  it  from  the  anemone,  only  by  its  colour,  its  figure,  8cc. 
We  perceive  nothing  but  within  ourselves.  It  is  only  by  habit,  only  by 
applying  different  senses  to  the  examination  of  the  same  object,  that  we 
are  at  least  able  to  separate  it  from  our  own  existence  ;  to  conceive  of  it 
as  distinct  from  ourselves,  and  from  the  other  bodies  with  which  we  are 
acquainted ;  in  a  word,  to  refer  to  outward  objects  the  sensations  that 
take  place  within  ourselves.  Our  ideas  come  to  us,  only  by  the  senses; 
there  are  none  innate  as  was  imagined  till  the  time  of  Locke,  who  has  al- 
lotted to  the  refutation  of  this  error  a  large  part  of  his  valuable  work  on 
the  Human  Understanding.  The  child  that  opens  its  eyes  to  the  light, 
is  prepared  for  the  acquisition  of  ideas,  by  this  merely,  that  it  has 
senses;  that  it  is  susceptible  of  impressions  from  the  objects  that  sur- 
round it. 

It  is  inaccurate,  however,  to  compare,  as  some  philosophers  have  done, 


*  I  ought  to  observe,  that  the  terms  thought  and  understanding  are,  in  my  opinion, 
synonymous ;  both  are  alike,  an  abridged  expression  of  the  whole  of  the  operations  of 
the  sensitive  centre. — Author's  Note, 


297 

the  brain  of  a  child  new  born  to  a  blank  tablet,  on  which  are  to  be  figured 
all  the  future  acts  of  his  intelligence.  If  sensation  came  only  from  with- 
out, if  the  external  senses  were  the  only  organs  that  could  send  impres- 
sions to  the  cerebral  centre,  the  understanding,  at  the  moment  of  birth, 
had  indeed  been  nothing,  and  the  comparison  of  its  organ  to  a  sheet  of 
white  paper,  or  to  a  slab  of  Parian  marble,  on  which  not  a  character  were 
drawn,  had  been  perfectly  correct.  But  we  are  compelled  to  acknow- 
ledge with  Cabanis,  two  sources  of  ideas  quite  distinct  from  each  other, 
the  external  senses,  and  the  internal  organs.  These  inward  sensations, 
springing  from  functions  that  are  carrying  on  with  us,  ar<*  the  cause  of 
those  instinctive  determinations  by  which  the  new-born  child  seizes 
the  nipple  of  its  mother,  and  sucks  the  milk  by  a  very  complicatedpro- 
cess,  which  directs  the  young  of  animals  the  moment  after  birth,  and 
sometimes  in  the  very  act  of  birth,  while  the  limbs  are  yet  engaged 
in  the  Vagina,  to  seize  upon  the  dug  of  their  dam.  Instinct,  as  the  au- 
thor just  quoted,  has  very  justly  observed,  sfv*ngs  from  impressions 
received  by  the  interior  organs,  whilst  reaso™ng  is  the  produce  of  exter- 
nal sensations;  and  the  etymology  of  the  w->rd  instinct,  composed  of  two 
Greek  words,  signifying  «  to  prick,"  *c-  "within,'*  agrees  with  the 
meaning  we  assign  to  it. 

These  two  parts  of  the  understanding,  reason  and  instinct,  unite  and 
blend  together,  to  produce  the  intellectual  system,  and  the  various  deter- 
minations of  mental  action.  But  the  part  that  each  bears  in  the  genera- 
tion of  ideas,  is  very  different  in  animals,  whose  grosser  external  senses 
allow  instinct  to  predominate;  and  in  man,  in  whom  the  perfection  of 
these  senses,  and  tbt  art  of  signs,  which  perpetrate  the  transient  thought, 
augment  the  power  of  reason,  while  .they  enfeeble  instinct.  It  is  easy  to 
conceive,  that  the  brain,  assailed  by  a  crowd  of  impressions  from  with- 
out, will  regard  less  attentively,  and  therefore  suffer  to  escape  the  greater 
part  of  those  that  result  from  internal  excitation.  Instinct  is  more  vigo» 
rous  in  savage  man,  and  its  relative  perfection  is  his  compensation  for  the 
advantages  which  superior  reason  brings  to  man  in  civilization.  The 
moral  and  intellectual  system  of  the  individual,  considered  at  different 
periods  of  life,  owes  more  to  internal  sensation,  the  less  it  is  advanced; 
for,  instinct  declines  as  reason  is  strengthened  and  enlarged. 

Thus,  though  all  the  phenomeixi  of  understanding  have  their  source  in 
physical  sensibility,  this  sensibi/ity  being  set  in  action  by  two  sorts  of 
impressions,  the  brain  of  an  in/ant  just  born,  has  already  the  conscious- 
ness of  those  which  spring  frojzi  the  internal  motion,  and  it  is  from  these 
impressions  that  it  executes  certain  spontaneous  movements,  of  whieh 
Locke  and  his  followers  coyfd  find  no  explanation  :  accordingly,  thepar- 
tizans  of  innate  ideas,  looked  i,-pon  them  as  the  strongest  confirmation  of 
their  system;  but  these  kleas, anterior  to  all  action  of  outward  objects  on 
the  senses,  are  simple,  few,  and  extending  to  a  very  small  number  of 
wants:  the  child  is  but  a  fevr  hours  old,  and  already  it  expresses  a  multi- 
tude of  sensations,  that  throng  upon  it  from  the  instant  of  its  birth,  sen- 
sations, which  have  passed  to  the  brain,  combined  themselves  there,  and 
entered  into  the  action  of  the  will,  with  a  velocity  which  equals,  if  it  does 
not  surpass,  that  of  light. 

It  U  only,  after  laying  down  between  the  sources  of  our  knowledge,  a 
very  exact  line  of  demarcation,  after  scrupulously  distinguishing  the  ra- 
tional from  the  instinctive  determinations,  acknowledging  that  age,  sex, 
temperament,  health,  disease,  climate,  and  habit,  which  modify  our  phy- 

2  P 


298 

sical  organization,  must,  by  a  secondary  effect,  modify  these  last, that  we 
can  possibly  understand  the  diversity  of  humours,  of  opinions,  of  charac- 
ters, and  of  genius.  He  who  has  well  appreciated  the  effect,  on  the  jWlg- 
ment  and  reason,  of  the  sensations  that  spring  from  the  habitual  state  of 
the  internal  organs,  sees  easily  the  origin  of  those  everlasting  disputes  on 
the  distinction  between  the  sensitive  and  the  rational  soul;  why  some 
philosophers  have  believed  man  solicited  for  ever  by  a  good  or  an  evil  ge- 
nius ;  spirits  which  they  have  personified  under  the  names  of  Oromazes, 
and  Arim'anes,  betwixt  whom  they  imagined  eternal  war;  the  contest  of 
the  soul  with  the  senses,  of  the  spirit  with  the  flesh,  of  the  concupiscent 
and  irascible  with  the  intellectual  principle,  .that  contradiction  which  St. 
Paul  laboured  under,  when  he  said  in  his  Epistle  to  the  Romans,  that  his 
members  were  in  open  war  with  his  reason.  These  phenomena  which 
suggest  the  conception  of  a  two-fold  being  (Homo  duplex,  Buffon,)  are 
nothing  but  a  necK^ary  strife  betwixt  the  determinations  of  instinct  and 
the  determinations  of^^on  5  between  the  often  times  imperious  wants 
of  the  organic  nature,  antN<he  judgment  which  keeps  them  under,  or  de- 
liberates on  the  means  of  SHisfying  them,  without  offending  received 
ideas  of  fitness,  of  duty,  of  relr^on,  &c. 

CLV.  A  being,  absolutely  desr*ute  Of  sensitive  organs,  would  possess 
only  the  existence  of  vegetation:  iiVesense  were  added,  he  would  not 
yet  possess  understanding,  because,  as^qndillac  has  shown,  the  impres- 
sions produced  on  this  only  sense,  wouldN^t  admit  of  comparison  ;  it 
would  end  in  an  inward  feeling,  a  perception ^pxistence,  and  he  would 
believe  the  things  which  affected  him  to  be  a  p^t  of  his  being.  The 
fundamental  truth,  so  completely  made  out  by  mode^  metaphysicians,  is 
found  distinctly  stated  in  the  writings  of  Aristotle  5*  a^d  there  is  room 
for  surprise,  that  that  father  of  philosophy  should  have  merely  recognised 
it,  without  conforming  to  its  doctrines  ;  but,  still  more  that  it  should 
,have  been  for  so  many  ages  disregarded  by  his  successors.  So  absolute- 
ly is  sensation  the  source  of  all  our  knowledge,  that  even  the  measure  of 
understanding  is  according  to  the  number  and  perfection  of  the  organs 
of  sense ;  and  that  by  successively  depriving  them  of  the  intelligent  be- 
ing, we  should  lower,  at  each  step,  his  intellectual  nature  5  whilst  the  ad- 
dition of  a  new  sense  to  those  we  now  possess,  might  lead  us  to  a  multi- 
tude of  unknown  sensations  and  ideas>  would  disclose  to  us  in  the  beings 
we  are  concerned  with,  a  vast  variety  of  new  relations,  and  would  greatly 
enlarge  the  sphere  of  our  intelligence, 

The  impression,  produced  on  any  organ,  by  the  action  of  an  outward 
body,  does  not  constitute  sensation  ;  h  is  farther  requisite,  that  the  im- 
pression be  transmitted  to  the  brain,  that  it  be  there  perceived,  that  is,  felt 
by  that  organ  ;  the  sensation  then  becomes  fitvception,  and  this  first  modi- 
fication supposes,  as  is  apparent,  a  centrak  orgwi,  to  which  the  impres- 
sions on  the  organs  may  be  carried.  The  cerebral  fibres  are,  more  or  less 
disturbed,  by  the  sensations  sent  to  them,  at  once>  from  all  the  organs  of 
sense  5  and  we  should  acquire  but  confused  notions  of  the  bodies  from 
which  they  proceed,  if  one  stronger  perception  did  not  silence,  as  it  were, 
the  rest,  and  fix  the  attention.  In  this  concentration  of  the  soul  upon  a 
single  object,  the  brain  is  feebly  stirred  by  many  sensations  that  leave  no 


*  JVil  est  in  intelleclu,  quod  non  prius  fuerit  in  scnsu  .-—Nisi  intellectus  ipset  as  Leibnitz 
has  Very  justly  added.    See  APPENDIX,  Note  E  E. 


299 

trace  ;  it  is  thus,  that  after  the  attentive  perusal  of  a  book,  we  have  lost 
the  sensations  that  were  produced  by  the  different  colour  of  the  paper  and 
the  letters. 

When  a  sensation  is  of  short  duration,  our  knowledge  of  it  is  so  light, 
that  soon  there  remains  no  remembrance  of  it.  It  is  thus,  that  we  do  not 
perceive,  every  time  we  wink,  that  we  pass  from  light  to  darkness,  and 
from  darkness  to  light.  If  we  fix  our  attention  on  this  sensation,  it  af- 
fects us  more  permanently.  After  occupying  one's  self,  for  a  given  time, 
with  a  number  of  things,  with  but  moderate  attention  to  each;  after  read- 
ing, for  instance,  a  novel,  full  of  events,  each  of  which  in  its  turn  has  in- 
terested us,  we  finish  it  without  being  tired  of  it,  and  are  surprised  at 
the  time  it  has  taken  up.-  It  is  because  successive  and  light  impressions 
have  effaced  one  another,  till  we  have  forgotten  all  but  some  of  the  prin- 
cipal actions.  Time  ought  then  to  appear  to  us  to  have  passed  rapidly, 
for,  as  Locke  has  well  said,  in  his  Essay  on  the  Human  Understanding, 
"  We  conceive  the  succession  of  times  only  by  that  of  our  thoughts." 

This  faculty,  of  occupying  one's  self  long  and  exclusively  with  the 
same  idea,  of  concentrating  all  the  intellectual  faculties  on  one  object,  of 
bestowing  on  the  contemplation  of  it  alone,  a  lively  and  well  supported 
attention,  is  found  in  greater  oi»less  strength  in  different  minds;  an^some 
philosophers  appear  to  me  to  have  explained,  very  plausibly,  the  differ- 
ent capacity  of  different  minds,  the  various  degrees  of  instruction  of 
which  we  are  capable,  by  tbe  degree  of  attention  we  are  a,He  to  give  to 
the  objects  of  our  studies. 

W^ho,  more  than  the  man  of  genius,  pauses  on  the  ^iamination  of  a 
single  idea,  considers  it  with  more  profound  reflection,  under  more  as- 
pects and  relations,  bestows  on  it,  in  short,  more  entire  attention  ? 

Attention  is  to  be  considered  as  an  act  of  the/will?  which  keeps  the 
organ  to  one  sensation,  or  prepares  it  for  that/ensation,  so  as  to  receive 
it  more  deeply.  To  look,  is  to  see  with  alien/on;  to  listen,  is  to  hear  at- 
tentively: the  smell,  the  taste,  in  the  same /ay,  are  fixed  upon  an  odour, 
or  a  flavour,  so  as  to  receive  from  them  tXe  fullest  impression.  In  all 
these  cases,  the  sensation  may  be  involun/ary,  but  the  attention  by  which 
it  is  heightened,  is  an  act  of  the  will.  7"*s  distinction  has  already  been 
well  laid  down  with  regard  to  the  feyiing?  which  is  only  the  touch  ex- 
erted under  the  direction  of  the  vrlW 

According  to  the  strength  or  fastness  of  the  impression  that  a  sensa- 
tion, or  an  idea  (which  is  but  a  ^nsation  operated  upon  by  the  cerebral 
organ,)  has  produced  on  the  fih/es  of  that  organ,  will  be  the  liveliness 
and  permanence  of  the  recolle/uon.  Thus,  we  may  have  reminiscence  of 
it,  or  recall  faintly  that  we  hAve  been  so  affected;  or  memory,  which  is  a 
representation  of  the  object*  with  some  of  its  characteristic  attributes,  as 
colour,  bulk,  &c. 

The  pains  that  appear  to  be  felt  in  limbs  which  we  have  lost,  have  not 
their  place  in  the  part  which  is  left;  the  brain  is  not  deceived,  when  it 
refers  to  the  foot,  the  sufferings  of  which  the  cause  is  in -the  stump,  after 
the  amputation  of  the  leg  or  thigh.  I  have  at  this  moment  before  me,  the 
case  of  a  woman  and  of  a  young  man,  whose  leg  and  thigh  I  took  off  for 
scrophulous  caries,  of  many  years  standing,  and  incurable  by  any  other 
means.  The  wound,  from  the  operation,  is  completely  cicatrised.  The 
stump  has  not  more  sensibility  than  any  other  part  covered  by  integu- 
ments, .since  it  may  be  handled  without  pain.  And  yet,  both  at  intervals, 
and  especially  when  the  atmosphere  is  highly  electrified,  complain  of 


300 

pains  in  the  limbs  which  they  have  lost  some  months  ago.  They  recog- 
nise them,  by  certain  characters,  for  those  of  their  disease.  They,  like 
all  perceptions,  are  manifestly  given  in  charge  to  the  memory,  which 
reproduces  them,  when  the  cerebral  organ  repeats  the  action,  once  occa- 
sioned by  the  impression  of  the  disease. 

Finally,  if  the  brain  is  easy  of  excitation,  and  at  the  same  time,  faith- 
ful in  preserving  the  impressions  it  has  received,  it  will  possess  the 
power  of  bringing  up  ideas  with  all  their  connected  and  collateral  ideas; 
of  reproducing  them,  in  some  sort,  by  recalling  the  entire  object,  whilst 
memory  presents  us  with  a  few  of  its  qualities  only.  This  creative  fa- 
culty is  called  the  imagination.  If  it  sometimes  produces  monsters,  it  is 
that  the  brain,  by  its  power  of  associating,  connecting,  combining  ideas, 
reproduces  them  in  an  order  not  according  to  nature,  gathers  them  un- 
der capricious  associations,  and  gives  occasion  to  many  erroneous  judg- 
ments. 

When  the  mind  brings  together  two  ideas,  when  it  compares  them, 
and  determines  on  their  analogy,  it  judges.  A  certain  number  of  judg- 
ments in  series,  form  a  reasoning.  To  reason,  then,  is  only  to  judge  of 
the  relations  that  exist  among  the  ideas  with  which  the  senses  supply  us, 
or  which  are  produced  by  Imagination. 

It  is,  with  the  faculties  of  the  soul,  as  with  those  of  the  body.  When 
called  into  full  exertion,  the  intellectual  organ  gains  vigour;  it  languishes 
in  too  long  impose.  If  we  exercise  certain  faculties  only,  they  are  greatly 
developed,  to  :,he  prejudice  of  the  rest.  It  is  thus,  that  by  the  study  of 
mathematics,  soundness  of  judgment  is  acquired  and  precision  of  reason- 
ing: to  the  extinction  of  imagination,  which  never  rises  to  great  strength 
without  injury  to  the  judging  and  reasoning  powers.  The  descriptive 
sciences  employ  especially  the  memory,  and  it  is  seldom  that  they  much 
enlarge  the  minds  of  tho^e  who  study  them  exclusively. 

CLVI.  Condillac  has  immortalized  his  name,  by  discovering,  the  first, 
and  by  demonstrating  irrefrtgibly  that  signs  are  as  necessary  to  the  for- 
mation as  to  the  expression  of  ideas;  that  language  is  not  lessvuseful  for 
thinking  than  for  speaking;  th-ut  if  we  could  not  attach  the  notions  once 
acquired  to  received  signs,  they  would  remain  always  unconnected  and 
incomplete;  since  we  should  hav*  no  power  to  associate  and  compare 
them,  and  to  determine  their  relations.  It  is  the  imperfection  or  the  to- 
tal want  of  signs,  for  fixing  their  idt^s,  ttvat  makes  the  infancy  of  the 
lower  animals  perpetual.  It  is  this  tint  makes  it  impossible  for  them 
to  transmit  to  another  generation,  or  evtn  to  Communicate  one  with  ano- 
ther, the  acquisitions  of  individual  expeiience:  which  experience  is  in- 
deed, by  the  same  cause,  restrained  within  /ery  narrow  limits,  and  con- 
fined to  a  few  simple  notions,  a  few  ideas  resting  merely  on  its  wants  and 
on  its  powers.  If  tfcere  were  not  signs  to  preserve  ideas,  and  to  connect 
them,  memory  would  be  nothing,  all  impressions  would  be  effaced,  soon 
after  they  were  felt,  all  collections  of  ideas  would  be  dissolved  as  soon 
as  formed,  (if  they  could  be  formed  at  all)  our  ignorance  would  be  in- 
definitely prolonged,  and  we  should  reach  old  age,  with  a  mind  still  in 
its  infancy. 

When  we  reflect  on  a  subject,  it  is  not  directly  on  the  ideas,  but  on  the 
words  expressing  them,  that  the  mind  operates:  we  should  never  have 
the  idea  of  numbers,  if  we  had  not  assigned  distinct  names  to  numbers, 
whether  single  or  collected.  Locke  speaks  of  some  Americans,  who  had 
no  idea  of  the  number  thousand,  because  the  words  of  their  language 


301 

expressed  nothing  beyond  the  number  twenty.  La  Coadamine  informs 
us,  in  his  narrative*  that  there  are  some  who  count  only  to  three,  and  the 
word  they  employ  to  express  the  number  is  so  complicated,  of  a  pronun- 
ciation so  long  and  difficult,  that,  as  Condillac  observed,  it  is  not  sur- 
prising, that  having  begun  with  a  method  so  inconvenient,  they  have  not 
been  able  to  advance  any  farther.  "  Deny,  (says  this  writer)  to  a  superior 
mind,  the  use  of  letters,  how  much  of  knowledge  you  put  out  of  his 
reach,  which  an  ordinary  capacity  will  attain  to  without  difficulty.  Go 
on,  and  take  from  him  the  use  of  speech,  the  lot  of  the  dumb  will  show 
you,  how  narrow  are  the  limits  within  which  you  confine  him.  Finally, 
take  from  him  the  use  of  all  sorts  of  signs,  let  him  be  unable  to  find  the 
least  sign  for  the  most  ordinary  thought,  and  you  have  an  ideot*." 

We  are  made  acquainted  by  travellers  with  certain  tribes,  so  backward 
in  the  art  of  expressing  their  ideas  by  signs,  that  they  seem  to  serve  as  a 
link  between  civilized  nations  and  certain  species  of  animals,  whose  in- 
stinct has  been  perfected  by  education.  One  might  even  assert,  that 
there  is  less  distance,  in  respect  to  intelligence,  from  a  man  in  that  ex- 
treme abasement,  to  the  higher  animals,  than  there  is  to  a  man  of  supe- 
rior genius,  such  as  Bacon,  Newton,  or  Voltaire. 

In  another  part  of  the  same  work,  afier  having  demonstrated,  that  lan- 
guages are  real  analytic  methods,  that  the  sciences  may  be  reduced  to 
well  constructed  languages,  he  shows  how  powerful  is  their  influence  in 
the  cultivation  of  the  mind.  But  he  shall  speak  himself  with  that  clear- 
ness of  expression,  which  is  the  characteristic  and  the  charm  of  his 
writings.  "  Languages  are  like  the  ciphers  of  the  geometricians;  they 
present  new  views  to  the  mind,  and  expand  it  as  they  are  brought  nearer 
to  perfection,  The  discoveries-  of  Newton  had  been  prepared  for  him, 
by  the  signs  that  had  been  already  contrived,  and  the  methods  of  calcu- 
lation that  had  been  invented.  If  he  had  arisen  sooner,  he  might  have 
been  a  great  man  to  his  own  age;  but  he  would  not  have  been  the  admi- 
ration of  ours.  It  is  the  same  in  other  departments." 

The  most  scanty  languages  have  been  formed  in  the  most  barren  coun- 
tries. The  savage  who  strays  along-  the  desert  shores  of  New  Zealand, 
needs  but  few  signs  to  distinguish  the  small  number  of  objects  that  ha- 
bitually impress  his  senses:  the  sky,  the  earth,  the  sea,  fire,  shells,  the 
fish  that  form  his  chief  food,  the  quadrupeds,  and  the  vegetable,  which 
are  but  few  in  number,  under  this  severe  climate,  are  all  that  he  has  to 
name  and  to  know:  accordingly,  his  vocabulary  is  very  small;  it  has 
been  given  to  us  by  travellers  in  the  compass  of  a  few  pages.  A  copious 
language,  one  capable  of  expressing  a  great  variety  of  objects,  of  sensa- 
tions, and  of  ideas,  supposes  high  civilization  in  the  people  among  whom 
it  is  spoken.  You  hear  complaints  of  the  perpetual  recurrence  of  the 
same  expressions,  the  same  thoughts,  the  same  images,  in  the  poetry  of 
Ossian:  but  living  amidst  the  barren  rocks  of  Scotland,  the  bards  could 
not  speak  of  things,  of  which  nothing,  on  the  soil  they  inhabited,  could 
supply  them  with  the  idea.  The  monotony  of  their  languages  was  in- 
volved in  that  of  their  impressions,  always  produced  by  rocks,  mists, 
winds,  the  billows  of  the  ireful  ocean,  the  gloomy  heath,  and  the  silent 
pine,  Sec.  The  repetition  of  the  same  expressions,  in  the  Scriptures, 
shows  that  civilization  had  not  made  the  same  progress  among  the  He- 


Kssai  sur  POrigine  des  Conuoissances  Humaines,  sec.  4. 


302 

brews,  as  among  the  Greeks  and  Romans.  The  connexion  there  is  be- 
tween the  genius  of  a  language  and  the  character  of  the  people  that 
speak  it,  the  influence  of  climate,  of  government,  and  of  manners  on  lan- 
guage, the  reasons,  why  the  great  writers,  in  every  department,  appear 
together,  at  the  very  time  in  which  a  language  reaches  its  perfection  and 
maturity,  Sec.  these  are  problems  that  suggest  themselves,  and  would 
well  merit  our  endeavours  to  obtain  solution,  did  not  the  investigation 
manifestly  lead  beyond  the  limits  of  our  inquiry. 

Though  Cond iliac  has  said,  repeatedly,  in  his  works,  that  all  the  ope-, 
rations  of  the  soul  are  merely  sensation  variously  transformed,  that  all 
its  faculties  are  included  in  the  single  one  of  sense;  his  analysis  of  thought 
leaves  still  much  doubt  and  uncertainty  on  the  real  character  and  relative 
importance  of  each  of  her  faculties. 

The  merit  of  dispersing  the  mist  which  covered  this  part  of  metaphy- 
sics remained  for  De  Tracy.  His  Elements  of  Ideology*,  leave,  nothing 
to  be  wished  for  on  this  subject:  I  shall  extract  some  of  its  main  results, 
referring  the  reader  for  the  rest  to  the  work. 

To  think  is  only  to  feel;  and  to  (eel,  is,  for  us,  the  same  as  to  exist; 
for  it  is  by  sensation  we  know  of  our  existence.  Ideas,  or  perceptions, 
are  either  sensations,  properly  so  called,  or  recollections,  or  relations 
which  we  perceive,  or,  lastly,  the  desire  that  is  occasioned  in  us  by  these 
relations.  The  faculty  of  thought,  therefore,  falls  in  the  natural  subdi- 
vision of  sensibility,  properly  termed  memory,  judgment,  and  will.  To 
feel,  properly  speaking,  is  to  be  conscious  of  an  impression;  to  remem- 
ber, is  to  be  sensible  of  the  remembrance  of  a  past  impression;  to  judge 
is  to  feel  relations  among  our  perceptions:  lastly,  to  will  is  to  desire 
something.  Of  these  four  elements,  sensations,  recollections,  judgments,  and 
desires,  are  formed  all  compound  ideas.  Attention  is  but  an  act  of  the 
will :  comparison  cannot  be  separated  from  judgment,  since  we  cannot 
compare  two  objects  without  judging  them:  reasoning  is  only  a  repetition 
of  the  act  of  judging:  to  reflect,  to  imagine,  is  to  compose  ideas,  analy- 
zable  into  sensations,  recollections,  judgments  and  desires.  This  sort  of 
imagination,  which  is  only  certain  and  faithful  memory,  ought  not  to  be 
distinguished  from  it. 

Finally,  want,  uneasiness,  inquietude,  desire,  passions,  &c.  are  either 
sensations  or  desires.  There  is  room,  therefore,  to  reproach  Condillac 
with  having  divided  the  human  mind  into  understanding  and  will  only: 
because  the  first  term  includes  actions  too  unlike,  such  as  sensation,  me- 
mory, judgment;  and  with  having  run  into  the  opposite  extreme,  in  the 
too  great  multiplication  of  secondary  divisions. 

CLVII.  Disorders  of  thought.  Philosophers  would  undoubtedly  attain 
to  a  much  profounder  knowledge  of  the  intellectual  faculties  of  man,  if 
they  joined  to  the  study  of  their  regular  and  tranquil  action,  that  of  the 
many  disordered  actions  to  which  they  are  liable.  It  is  not  enough,  if 
we  would  understand  them  aright,  to  watch  their  operation  when  the  soul 
is  undisturbed  and  at  ease:  we  must  follow  it  in  its  perturbations  and 
wanderings :  we  must  see  its  powers,  now  separating  themselves  from 
those  with  which  they  ought  to  act;  now  combining  with  them  under 
false  perceptions :  sometimes,  altogether  drooping,  and  sometimes  start- 
ing into  an  extreme  violence  of  action,  of  which  we  can  neither  mistake 


Elemens  dldeologie,  par  M.  Destutt^Tracy,  senateur,  Membre  de  1'Institut. 


303 

the  importance  nor  the  nature ;  and,  as  the  greater  part  of  our  ideas  are 
derived  from  the  analogies  we  are  able  to  discern  among  the  objects  that 
supply  them,  amidst  these  troubles  of  human  passion  and  human  reason, 
we  learn  to  conceive  more  profoundly  of  their  nature,  than  if  we  had 
been  satisfied  with  observing  them  in  the  calm  of  their  natural  condition. 
The  observation  of  mania  is  yet  too  imperfect  in  the  number,  variety, 
and  precision  of  its  facts,  to  fix  the  classification  of  the  species  of  mental 
alienation,  according  to  the  intellectual  faculty  that  is  disordered  in  each. 
Professor  Pinel  has,'  nevertheless,  ventured  to  ground  his  distinctions  of 
the  species  of  mania  on  the  labours  of  modern  psychologists,  and  shown 
that  all  might  be  referred  to  five  kinds,  which  he  marks  by  the  names  of 
melancholy,  of  mania  without  delirium,  mania  with  delirium,  dementia, 
and  idiotcy*.  In  the  first  four  kinds,  there  is  perversion  of  the  mental  fa- 
culties, which  are  in  languid  or  excessive  action.  We  are  not  to  look 
for  the  cause  of  these  derangements  in  vice  of  original  conformation  ; 
for,  melancholy,  mania  with  or  without  delirium,  and  madness,  scarcely 
ever  appear  before  puberty.  It  is  agreed,  among  observers,  that  almost 
all  maniacs  have  become  so,  between  twenty  and  forty  years  old  :  that 
very  few  have  lost  their  reason  either  before  or  after  this  stormy  period 
of  life,  wherein  men,  yielding,  by  turns,  to  the  torments  of  love  and  of  am- 
bition, of  fear  and  of  hope,  to  the  sweet  illusions  of  happiness,  and  the 
realities  of  suffering,  consumed  with  passions  for  ever  revivings  often  re- 
pressed, and  rarely  satisfied,  feel  their  intellectual  powers  impaired,  an- 
nihilated, or  abused  by  that  tempest  of  the  moral  nature,  which  has  well 
been  compared  to  the  storms  which,  in  their  violence,  lay  desolate  the 
flourishing  earth. 

We  are  compellsd  to  grant,  that  our  acquaintance  with  the  structure 
of  the  brain  and  of  the  nerves  is  too  imperfect,  thai  dissections  of  the 
bodies  of  maniacs  have  been  too  few,  and  those  often  by  physiciansf  too 
little  familiar  with  the  minute  structure  of  the  sensitive  organ,  to  war- 
rant us  in  asserting  or  denying,  that  derangement  of  intellect  depends 
constantly  on  organic  injury;  though  it  is  highly  probable,  many  facts,  at 
least,  collected  by  observers,  who,  like  Morgagni,  deserve  the  utmost 
confidence,  authorise  the  belief,  that  the  consistence  of  the  brain  is  in- 
creased in  some  maniacs  who  are  distinguished  by  the  most  obstinate  and 
unvarying  adherence  to  their  ruling  ideas ;  that  it  is,  on  the  other  hand, 
soft,  watery,  and  in  a  kind  of  incipient  dissolution,  in  some  others,  whose 
incoherent  ideas  after  their  aptitude  for  association,  and  for  transforma- 
tion into  judgments  is  gone,  succeed  one  another  rapidly,  and  seem  to 
pass  away  without  a  trace,  Etc. 

If,  in  the  multitude  of  maniacs,  the  organ  of  the  understanding  suffer 
only  imperceptible  injury,  it  is  very  remarkably  changed  in  idiots.  The 
almost  entire  obliteration  of  the  intellectual  faculties,  which  constitutes 
idiocty,  when  it  is  not  brought  on  by  some  strong  and  sudden  shock,  some 
unexpected  and  overwhelming  emotion  breaking  down  at  once  all  the 
springs  of  thought,  when  it  is  an  original  defect,  always  connected  with 
mal-conformatiori  of  the  skull,  with  the  constraint  of  the  organs  it  en- 
closes. These  defects  of  organization  lie,  as  M.  Pinel  observes,  in  the 


*   For  move  ample  explanation  I  must  refer  to  the  work.     Traite  medico-philosophique 
tnir  r Alienation  mentals  on  la  Manic,  par.  P.  Pinel.     Paris,  1800.—  Copland. 
f  This  censure  is  especially  applicable  to  the  researches  of  Dr.  Greding. — Copland, 


304 

excessive  smalhiess  of  the  head,  to  the  whole  stature,  or  to  the  want  of 
proportion  among  the  different  parts  of  the  skull.  Thus  in  the  idiot, 
whose  head  is  given  in  the  work  on  mania  (pi.  2.  fig.  6.)  it  is  only 
the  tenth  of  the  whole  height,  whilst  it  should  be  something  more  than  a 
seventh,  if  we  take  the  Apollo  of  Belvidere  as  the  type  of  the  ideal  per- 
fection of  the  human  figure.  An  idiot,  whom  I  occasionly  see,  has  the 
occipital  extremity  of  the  head  so  much  contracted,  that  the  large  extre- 
mity of  the  oval  formed  by  the  upper  face,  instead  of  being  placed  at  the 
back,  as  in  other  men,  is,  on  the  contrary,  turned  forwards  and  answers 
to  the  forehead,  which  itself  slopes  towards  the  sinciput.  The  vertical 
diameter  of  the  skull  is  inconsiderable.  The  head,  thus  shortened  from 
above  downwards,  is  much  flattened  on  the  sides.  The  hands  and  feet 
are  very  small,  and  often  cold  $  the  genitals,  on  the  contrary  are  ex- 
tremely large*. 

In  two  other  children,  equally  idiots,  and  now  in  the  Hospital  of  St. 
Louis,  the  skull,  very  large  behind,  ends  in  a  very  contracted  extremity, 
and  the  forehead  is  very  short,  and  not  more  than  two  inches  and  a  half 
wide,  measuring  from  the  semi-circular  process,  which  terminates,  at  the 
upper  part  of  the  temporal  fossa,  to  the  commencement  of  the  same  pro- 
cess on  the  other  side.  The  excessive  growth  of  the  genitals  is  not  less 
conspicuous  ;  they  are,  in  these  two  children,  one  ten,  the  other  twelve 
years  old,  as  well  as  in  the  first  of  whom  I  spoke,  who  is  fourteen,  of 
larger  size  than  is  commonly  seen  after  the  appearance  of  puberty. 
There  is  nothing  to  indicate  that  this  season  is  attained  by  these  three 
idiots. 

The  same  excess  of  growth  is  found,  more  conspicuously  among  the 
cretins  of  the  Valais,  idiots  who  (in  conseqnence  of  a  weak  and  degraded 
organization)  are  prone  to  lascivousness  and  the  most  frequent  onanism. 

This  sort  of  opposition  in  the  relative  energy  of  the  intellectual  organ, 
and  of  the  system  of  reproduction,  in  the  developement  of  the  brain,  and 
that  of  the  parts  of  generation  is  a  phenomenon  which  must  strongly  in- 
terest the  curiosity  and  engage  the  attention  of  physiologists.  Who  is 
there  unacquainted  with  that  enervation  of  the  understanding,  that  in- 
tellectual and  physical  debility,  which  indulgence  in  the  pleasures  of  love 
brings  on,  if  we  exceed  ever  so  little  the  bounds  of  scrupulous  modera- 
tion? Castration  modifies  the  moral  character  of  men  and  animals,  at 
least  as  powerfully  as  their  physical  organization,  as  M.  Cabanis  has 
shown,  in  treating  of  the  influence  of  the  sexes  on  the  origin  and  growth 
of  the  moral  and  intellectual  powers. 

CLVIII.  Our  physical,  therefore,  holds  our  moral  nature  under  a 
strict  and  necessary  dependence  :  our  vices  and  our  virtues,  sometimes 
produced  and  often  modified  by  social  education,  are  frequently,  too,  re- 
sults of  organization.  To  the  conclusive  proofs  which  the  philosopher  I 
have  just  named,  who  is  an  honour  to  his  profession,  brings  forward  of  the 
influence  of  the  physical  on  the  moral  human  being,  I  will  only  add  a  single 
observation.  It  is  not  certainly,  the  first  that  has  been  made  of  the  kind; 
but  none  such,  I  believe,  has  yet  been  published.  The  reader  recollects, 
I  have  no  doubt,  the  old  woman  of  whom  I  have  spoken  in  treating  of  the 


*  As  a  general  rule,  the  intellectual  faculties  are  in  an  inverse  ratio  to  the  magnitude 
of  the  genital  organs.  This  is  particularly  exemplified  in  the  ancient  statuary,  and  » 
supported  by  comparative  anatomy. —  Gadman. 


305 

motions  of  the  brain,  which  an  enormous  caries  of  the  bones  of  the. 
skull  gave  an  opportunity  of  observing  in  her.  I  wiped  off  the  sanious 
matter  which  covered  the  dura  mater,  and  I,  at  the  same  time,  questioned 
the  patient  on  her  situation :  as  she  felt  no  pain  from  (.he  compression  of 
the  cerebral  mass,  I  pressed  down  lightly  the  pledget  of  lint,  and  on  a 
sudden  the  patient,  who  was  answering  my  questions  rationaily,  stopped 
in  the  midst  of  a  sentence,  but  she  went  on  breathing,  and  her  pulse  con- 
tinued to  beat :  I  withdrew  the  pledget ;  she  said  nothing  :  I  asked  her  if 
she  remembered  my  last  question  :  she  said  not.  Seeing  that  the  expe- 
riment was  without  pain  or  danger,  I  repeated  it  three  times,  and  thrice 
I  suspended  all  feeling  and  all  intellect. 

A  man  trepanned  for  a  fracture  of  the  skull,  with  effusion  of  blood  and 
pus  on  the  dura  mater,  perceived  his  intellectual  faculties  going,  the 
consciousness  of  existence  growing  benumbed  and  threatening  to  ceasey 
at  the  interval  of  each  dressing,  in  proportion  as  the  fluid  collected. 

There  are  surgical  observations  on  wounds  of  the  head,  containing  se- 
veral facts  that  may  be  connected  with  the  preceding  observations.  There 
is  no  one  who  has  had  syncope  of  more  or  less  continuance,  but  knows 
that  the  state  is  without  pain  or  uneasiness,  and  leaves  no  consciousness 
of  what  passed  while  it  lasted.  It  is  the  same  after  an  apoplexy,  a  fit 
of  epilepsy,  &c. 

The  history  of  temperament  supplies  us  with  too  many  examples  of 
the  strict  connexion  which  there  is  between  the  physical  organization  and 
the  intellectual  and  moral  faculties,  to  leave  any  necessity  for  dwelling 
longer  on  this  truth,  which  no  one  questions;  but  which  no  philosopher 
has  yet  followed  into  all  its  consequences. 

CLIX.  An  English  writer,  in  a  work  on  the  history  of  mental  aliena- 
tion*, has  traced,  better  than  had  before  been  done,  the  physiological 
history  of  the  passions,  which  he  looks  upon  as  mere  results  of  organiza- 
tion, ranking  them  among  the  phenomena  of  animal  economy,  and  with 
abstraction  of  any  moral  notion  that  might  attach  to  them. 

All  passion  is  directed  to  the  preservation  of  the  individual  or  the  re- 
production of  the  species.  They  may  be  distinguished,  therefore,  like 
the  functions,  into  two  classes!'  In  the  second,  we  should  find  parental 
love,  and  all  the  affections  that  protect  our  kind  through  the  helplessness 
of  its  long  infancy. 

But  Crichton,  with  the  greater  part  of  metaphysicians  and  physiolo- 
gists, appears  to  me  to  have  settled  incorrectly  the  meaning  that  should  be- 
long to  the  word  passion.  When  he  gives  this  name  to  hunger,  an  in- 
ward painful  sensation,  the  source  of  many  determinations  of  many  kinds, 
a  powerful  mover  of  savage  «nd  civilized  man, —  to  the  anxiety  which  at- 
tends the  breathing  an  air  deficient  in  oxygen,-— to  the  impressions  of  ex-' 
cessive  heat  and  cold,— to  the  troublesome  sensations  produced  by  the  ac- 
cumulation of  urine  and  fecal  matter,— to  the  feeling  of  weariness  and 
fatigue  that  is  left  by  violent  exertions, — he  confounds  sensation  with  the 
passions  or  desires  which  may  spring  from  it. 

It  is  to  avoid  extreme  wants,  of  which  a  vigilant  foresight  perceives  afar 
off  the  possibility — it  is  to  satisfy  all  the  factitous  wants  which  society 
and  civilization  have  created,  that  men  condemn  themselves  to  those  agi- 

*  An  Inquiry  into  the  Nature  and  Origin  of  Mental  Derangement— London,  If  98, 
2vols.  8vo.< 
t  See  APPENDIX,  Note  B  £. 

20 


306 

f atlotts,  of  which  honour,  reputation,  wealth  and  power,  are  the  uncertain 
aim.  Our  passions  have  not  yet  been  analyzed  with  the  same  care  as  our 
ideas:  no  one  has  yet  duly  stated  the  differences  there  are,  in  respect  to 
their  number  and  energy,  betwixt  savage  man,  and  man  in  the  midst  of 
civilized  and  enlightened  society. 

As  the  habitual  state  of  the  stomach,  of  the  lungs,  of  the  liver  and 
internal  organs,  is  conncted  with  certain  sets  of  ideas  ; — as  every  vivid  sen- 
sation of  joy  or  distress,  of  pleasure  or  pain,  brings  on  a  feeling  of  anxie- 
ty in  the  prsecordia, — the  ancients  placed  in  the  viscera  the  seat  of  the 
passions  of  the  soul:  they  placed  courage  in  the  heart,  anger  in  the  liver, 
joy  in  the  spleen,  Sec.  Bacon  and  Van  Helmont  seated  them  in  the  sto- 
mach; Lecat  in  the  nervous  plexuses;  other  physiologists  in  the  gang- 
lions of  the  great  sympathetic,  Sec.  But  have  they  not  confounded  the 
effect  with  the  cause?  the  appetite  with  the  passion  to  which  it  disposes? 
The  appetites,  out  of  which  the  passions  spring,  reside  in  the  organs 
they  suppose  only  instinctive  determinations,  whilst  passion  carries  with 
it  the  idea  of  intellectual  exertion.  Thus,  the  accumulation  of  semen  in 
the  vesiculae  which  serve  for  its  reservoirs,  excites  the  venereal  appetite, 
quite  distinct  from  the  passion  of  love,  though  often  its  determining 
cause.  Animals  have  scarcely  more  than  appetite,  which  differs  as  much 
from  passion  as  instinct  from  intelligence.  However,  the  brain  is  not  to 
be  considered  as  the  primitive  seat  of  the  passions*,  as  is  done  by  the 
greater  number  of  philosophers.  Of  all  the  feelings  of  man,  the  most 
lasting,  the  most  sacred,  the  most  passionate,  the  least  susceptible  of  in- 
jury from  all  the  prejudices  of  the  social  state,  maternal  love,  is  surely 
not  the  result  of  any  intellectual  combination,  of  any  cerebral  action:  it 
is  in  the  bowels  (entrailles)  its  source  lies :  thence  it  springs,  and  all  the 
efforts  of  imagination  cannot  attain  it  for  those  who  have  not  been  blevss- 
ed  with  a  mother's  name. 

All  passion  springs  from  desire,  and  supposes  a  certain  degree  of  exalta- 
tion of  the  intellectual  faculties.  The  shades  of  the  passions  are  infi- 
nite: they  might  be  all  arranged  by  a  systematic  scale;  of  which  indif- 
ference would  be  the  lowest  gradation,  and  maniacal  rage  the  highest.  A 
man  without  passion,  is  as  impossible  to  imagine,  as  a  man  without  de- 
sires ;  yet  we  distinguish,  as  passionate,  those  whose  will  rises  power- 
fully towards  one  object  earnestly  longed  for.  In  tne  delirium  of  the 
passions,  we  are  for  ever  making  unconsciously,  false  judgments,  of  which 
the  error  is  exaggeration.  A  man  recovering  from  a  seizure  of  fear,  laughs 
at  the  object  of  his  terror.  Look  at  the  lover  whose  passion  is  extinct! 
freed,  at  last,  from  the  spell  that  enthralled  him,  all  the  perfections  with 
which  his  love  had  invested  its  object  are  vanished  :  the  illusion  has  pass- 
ed away;  and  he  can  almost  believe  that  it  is  she  who  is  no  longer  the 
same,  while  himself  alone  is  changed  :  like  those  maniacs  who,  on  their 
return  to  reason,  wonder  at  the  excesses  of  their  delirium,  and  listen,  in- 
credulously, to  the  relation  of  their  own  actions.  The  ambitious  man 
feeds  on  imaginations  of  wealth  and  power.  He  who  hates,  exaggerates 


*  If  we  analyzed  the  passions  carefully,  it  would  be  right  to  distinguish  those  which 
are  common  to  all  men,  which  appertain  to  our  physical  wants  and  to  our  nature,  from 
certain  caprices  of  the  mind  which  have  been  honoured  with  the  name  of  passion,  as 
Avarice,  ambition,  &c.  which  should  be  referred  to  kinds  of  mental  derangement,  and 
classed  as  species,  of  monomania. 


307 

the  defects  of  theobject  of  his  hatred,  and  sees  crimes  in  his  slightest 
faults. 

The  affections  of  the  soul,  or  the  passions,  whether  they  come  by  the 
sense,  or  some  disposition  of  the  vital  organs  favour  their  birth  and 
growth,  may  be  ranged  in  two  classes,  according  to  their  effects  on  their 
economy.  Some  heighten  organic  activity  ;  such  are  joy,  courage,  hope, 
and  love;  whilst  others  slacken  the  motions  of  life,  as  fear,  grief,  and 
hatred.  And  others  there  are,  that  produce  the  two  effects  alternately, 
or  together.  So  ambition,  anger,  despair,  pity,  assuming,  like  the  other 
passions,  an  infinite  variety  of  shades,  according  to  the  intensity  of  their 
causes,  individual  constitution,  age,  sex,  &c.  at  times  increase,  at  times 
abate,  depress  or  exalt  the  vital  action,  and  exalt  or  depress  the  power  of 
the  organs. 

The  instances  which  establish  the  powerful  influence  of  the  passions  on 
the  animal  economy  are  too  frequent  to  need  reciting.  Writers,  in  every 
department  furnish  such  as  show  that  excess  of  pleasure,  like  excess  of 
pain,  joy  too  lively  or  too  sudden,  as  grief  too  deep  and  too  unexpected, 
may  bring  on  the  most  fatul  accidents  and  even  death.  Without  collect- 
ing in'  this  place*  all  the  observations  of  the  sort  with  which  books  swarm, 
I  shall  content  myself  with  referring  to  those  who  have  brought  together 
the  greatest  number  of  facts  under  one  point  of  view;  as  Haller,  in  his 
Physiology;  Tissot,  in  his  Treatise  on  Diseases  of  the  Nerves;  Lecamus, 
in  his  work  on  Diseases  of  the  Mind;  Bonnefoy,  in  a  paper  on  the  Pas- 
sions of  the  Soul;  inserted  in  the  fifth  volume  of  the  Collection  of  Prizes, 
adjudged  by  the  Academy  of  Surgery. 

The  effects  of  the  passions  are  not,  for  their  uniformity,  the  less  inex- 
plicable. How,  and  why  does  anger  give  rise  to  madness,  to  suppres- 
sion of  urine,  to  sudden  death  ?  How  does  fear  determine  paralysis,  con- 
vulsions, epilepsy,  8cc.  ?  Why  does  excessive  joy,  a  sense  of  pleasure 
carried  to  extremity,  produce  effects  as  fatal  as  sad  and  afflicting  impres- 
sions? In  what  way  can  violence  of  laughter  lead  to  death  ?  Excess  of 
laughter  killed  the  painter  Zeuxis  and  the  philosopher  Chrysippus,  ac- 
cording to  the  relation  of  Pliny.  The  conversion  of  the  reformed  of  the 
Cevennes,  under  Louis  XIV.  was  effected  by  binding  them  on  a  bench, 
and  tickling  the  soles  of  their  feet,  till  overpowered  by  this  torture,  they 
abjured  their  creed  :  many  died  in  the  convulsions  and  immoderate 
laughterj  which  the  tickling  excited*.  A  hundred  volumes  would  be  in- 
sufficient to  detail  all  the  effects  of  the  passions  on  physical  man  ;  how 
many  would  it  take  to  tell  their  history,  in  moral  man,  from  their  dark 
origin,  through  all  their  stages  of  growth,  in  the  infinite  variety  of  their 
characters*  and  in  all  their  evanescent  shades  ! 

The  inquiries  of  Physiology  are  directed  to  the  functions  that  are  car- 
ried on  in  physical  man,  to  the  functions  of  life  :  the  study  of  the  nobler 
parts  of  ourselves,  of  those  wonderful  faculties  which  place  our  kind 
above  all  that  have  motion  or  life  ;  in  a  word  the  knowledge  of  moral  and 
intellectual  man  belongs  to  the  science  known  by  the  name  of  metaphy- 


*  This  instance,  however,  does  not  illustrate  the  influence  of  the  passions  on  the  vital 
functions.  It  showsmerely  the  effects  of  irritation  of  the  extremities  of  nerves  upon  the 
functions  of  other  nerves  either  of  the  same,  or  of  a  different  order,  which  effects  are 
either  produced  by  a  direct  medium  of  communication  with  the  nerves  first  affected,  or 
then  by  means  01' the  nervous  centres. —  Copland. 


308 

sics,  or  psychology,  of  analysis  of  the  understanding,  but  better  described 
by  that  applied  to  it  by  the  writers  of  our  days,  ideology.  On  this  sci- 
ence, you  may  consult  with  advantage,  the  philosophical  works  of  Plato 
and  Aristotle,  among  the  ancients  ;  of  Bacon,  Hobbes,  Locke,  Condillac, 
Bonnet,  Smith,  Reid,  Dugald,  Stewart,  Brown,  Cabanis,  and. Tracy, 
among  the  moderns. 

CLX.  Of  sleep  and  waking.  The  causes  of  excitation  to  which  our 
organs  are  exposed  during  waking,  tend  to  increase  progressively  their 
action  ;  the  pulsations  of  the  heart,  for  instance,  are  much  more  frequent 
in  the  evening  than  in  the  morning,  and  this  motion,  gradually  accelera- 
ted, would  soon  be  carried  to  a  degree  of  activity  incompatible  with  the 
continuance  of  life,  did  not  sleep  daily  temper  this  energy,  and  bring  it 
down  to  its  due  measure.  Fever  is  occasioned  by  long  continued  want  of 
sleep,  and  in  all  acute  diseases,  the  exacerbation  comes  on  towards  even- 
ing, the  night's  sleep  abates  again  the  high  excitation  of  power:  but  this 
state  of  the  animal  economy,  so  salutary  and  so  desirable  in  all  sthenic 
affections,  is  more  injurious  than  useful  in  diseases,  consisting  chiefly  in 
extreme  debility.  Adynamy  shows  itself, almost  always,  in  the  morning,in 
putrid  fevers ;  and  petechiae,  a  symptom  of  extreme  weakness,  break  out 
during  sleep.  This  state  is,  likewise  favourable  to  the  coining  on  and  to 
the  progress  of  gangrene,  and  this  is  a  pathological  fact  well  ascertained. 
In  all  the  cases  I  have  mentioned,  sleep  does  not  improve  the  condition 
of  the  patients ;  a  thing  easy  to  conceive,  since  it  only  adds  to  accidental 
debility,  the  essential  characteristic  of  the  disease,  weakness  which  is  al- 
so its  principal  characteristic. 

Sleep,  that  momentary  interruption  in  the  communication  of  the  senses 
with  outward  objects,  may  be  defined  the  repose  of  the  organs  of  sense, 
and  of  voluntary  motion.  During  sleep,  the  inward  or  assimilating  func- 
tions are  going  on  :  digestion,  absorption,  circulation,  respiration,  secre- 
tion, nutrition,  are  carried  on;  some  as  absorption  and  nutrition*  with 
more  energy  than  during  waking,  whilst  others  are  evidently  slackened. 
During  sleep,  the  pulse  is  slower  and  weaker,  inspiration  is  less  frequent, 
insensible  perspiration,  urine,  and  all  other  humours  derived  from  the 
blood,  are  separated  in  smaller  quantity.  Absorption  is,  on  the  contra- 
ry, very  active  :  hence  the  danger  of  falling  asleep  inithe  midst  of  a  noxi- 
ous air.  It  is  known  that  the  marshy  effluvia,  which  make  the  Com- 
pagna  di  Roma  so  unhealthy,  bring  on,  almost  inevitably,  intermittent 
tevers,  when  the  night  is  passed  there,  whilst  travellers,  who  go  through 
•without  stopping,  are  not  affected  by  itf. 


*  Nutrition  is  evidently  more  active  during1  sleep,  in  early  life,  especially  in  childhood; 
and,  in  many  constitutions  and  habits  of  body,  it  appears  equally  active,  during  this 
state,  through  the  middle  stages  of  life  ;  but  as  soon  as  the  period  of  decay  approaches, 
absorption  appears  to  predominate,  while  on  the  contrary,  nutrition  gradually  languishes 
more  and  more,  during  sleep,  as  age  advances.  In  the  middle  periods  of  existence  it  is 
difficult  to  determine  whether  absorption  or  nutrition  is  augmented  during  this  state  : 
the  difference  cannot  always  be  correctly  appreciated ;  but  we  generally  find  that  when 
the  one  is  increased  the  other  is  generally  diminished,  both  functions  being  seldom  aug- 
mented or  impaired  at  the  same  time. —  Copland. 

f  Tins  is  quite  as  much  the  result  of  the  low  state  of  the  nervous  and  vital  energies 
of  the  system  during  sleep.  The  vital  powers  at  that  time  are  not  under  the  impression 
of  the  excitements  communicated  through  the  medium  of  the  nerves  of  sensation  and 
motion ;  the  operations,  indeed,  of  this  part  of  the  nervous  system  are  for  a  time  suspend- 
ed, and  consequently  the  vital  functions  lose  part  of  their  energy,  and  are  open  to  the 


809 

-  The  human  body  is  a  tolerable  representation  of  the  centripetal  and 
centrifugal  powers  of  ancient  physics.  The  motion  of  many  of  the  sys- 
tems which  enter  into  its  structure  is  directed  from  the  centre  to  the  cir- 
cumference :  it  is  a  real  exhalation  that  carries  out  the  result  of  the  per- 
petual destruction  of  the  organs ;  such  is  the  action  of  the  heart,  of  the 
arteries,  and  of  all  the  secretory  glands.  Other  actions,  on  the  contrary, 
take  their  direction  from  the  circumference  to  the  centre ;  and  it  is  by 
their  means  that  we  are  incessantly  deriving  from  the  food  we  take  into 
the  digestive  passages,  from  the  air  which  penetrates  the  interior  of  the 
lungs,  and  covers  the  surface  of  the  body,  the  elements  of  its  growth,  and 
repair.  These  two  motions,  in  opposite  directions,  continually  balance 
each  other,  prevailing  by  turns,  according  to  the  age,  the  sex,  the  state  of 
sleep  or  waking.  During  sleep,  the  motions  ten'd  from  the  periphery  to 
the  centre,  (Hipp.)  and  if  the  organs  that  connect  us  with  outward  objects 
are  in  repose,  the  inward  parts  are  in  stronger  exertion.  Somnus  labor  vi- 
sceribus  (Hipp.)  A  man,  aged  forty  years,  taken  with  a  kind  of  imbecili- 
ty, remained  about  a  year  and  a  half  at  the  Hospital  of  St.  Louis,  for  the 
cure  of  some  scrophulous  glands :  all  that  long  time  he  remained  con- 
stantly in  bed,  sleeping  five  sixths  of  the  day,  tortured  with  devouring 
hunger,  and  passing  his  short  moments  of  waking  in  eating  5  his  diges- 
tion was  always  quick  and  easy;  he  kept  up  his  plumpness,  though  the 
muscular  action  was  extremely  languid,  the  pulse  very  weak  and  very 
slow.  In  this  man,  who,  to  use  the  expression  of  Bordeu,  lived  under 
the  dominion  of  the  stomach,  the  moral  affections  were  limited  to  the  de- 
sire of  food  and  of  repose.  Oppressed  with  irresistible  sloth,  it  was  ne- 
ver without  great  difficulty  that  he  could  be  brought  to  take  the  slight- 
est exercise. 

Waking  may  be  looked  upon  as  a  state  of  effort  and  of  considerable 
expenditure  of  the  sensitive  and  moving  principle,  by  the  organs  of  sen- 
sation and  of  motion.  This  principle  would  have  been  soon  exhausted 
by  this  uninterrupted  effusion,  if  long  intervals  of  repose  had  not  favoured 
its  restoration.  This  interruption  in  the  exercise  of  the  senses  and  of 
voluntary  motion,  is  of  duration  corresponding  to  that  of  their  exertion. 
I  have  already  said,  that  there  are  functions  of  such  essential  importance 
to  life,  that  their  organs  could  be  allowed  but  short  moments  of  repose^ 
but  that  these  intervals  are  brought  so  close  to  each  other,  that  their  time 
is  equally  divided  between  activity  and  repose.  The  functions  which 
keep  up  our  connexion  with  outward  objects,  could  not  be  without  the 


influence  of  such  causes  of  disease  as  generally  invade  them  during1  states  of  debility 
and  exhaustion,  or  when  they  are  not  otherwise  acted  on  eitheir  by  external  or  internal 
stimuli. 

It  may  be  justly  asserted  that  the  operations  of  the  system  languish  in  a  degree  pro. 
pprtionate  to  that  in  which  they  are  deprived  of  their  natural  excitements,  whether  these 
excitements  are  food,  air,  exercise,  amusement,  8cc. — whether  they  are  coporeal  or 
mental — or  whether  they  are  external  or  internal  with  respect  to  their  modes  of  exist- 
ence, and  to  their  manner  of  operation  on  the  body.  When,  therefore,  the  system  is 
deprived  of  apart  of  these  excitements, — of  the  influence  of  the  mental  operations,  and 
of  the  excitements  of  sensation  and  voluntary  motion,  as  it  is  during1  sleep,  its  operations 
are  necessarily  more  languid  and  weak,  and  consequently  it  is  more  ready  impressed  by 
many  during-  the  waking  state.  The  condition  of  the  night  air,  in  respect  to  tempera- 
ture, and  the  concentration  of  the  moisture  and  of  the  terrestrial  exhalations  in  the  low- 
er regions  of  the  atmosphere,  especially  in  particular  situations,  also  contribute  to  the 
effect  mentioned  in  the  text.  —  Copland. 


310 

capacity  of  continuing,  for  a  certain  time,  in  a  state  of  equal  activity;  for 
it  is  easy  to  see  how  imperfect,  relations  interrupted  at  every  moment, 
would  have  been:  their  reposej  which  constitutes  sleep,  is  of  equal  dura- 
tion. 

The  duration  of  sleep  is  from  a  fourth  to  a  third  of  the  day:  few  sleep 
less  than  six  hours,  or  more  than  eight.  Children,  however,  require 
longer  sleep;  the  more,  the  nearer  they  are  to  the  period  of  their  birth. 
Old  men,  on  the  contrary,  have  short  sleep,  light,  and  broken;  as  if,  says 
Grimaud,  according  to  Stahl's  notions,  children  foresaw  that  in  the  long 
career  before  them,  there  were  time  enough  for  performing,  at  leisure, 
all  the  acts  of  life,  while  old  men  near  to  their  end,  felt  the  necessity  of 
hurrying  the  enjoyment  of  a  good  already  about  to  escape. 

If  the  sleep  of  a  child  is  long,  and  deep,  and  still,  it  is  the  wonderful 
activity  of  the  assimilating  functions  that  makes  it  so,  and  perhaps  the 
habit  itself  of  sleep,  in  which  he  has  passed  the  first  nine  months  of  his 
life,  or  all  the  time  before  his  birth.  In  advanced  age,  the  internal  func- 
tions grow  languid;  their  organs  no  longer  engage  the  action  of  the  prin- 
ciple of  life;  and  the  brain  is  moreover  so  crowded  with  ideas,  that  it  is 
almost  always  kept  awake  by  them.  Carnivorous  animals  sleep  longer 
than  graminivorous,  because  during  waking  they  are  more  in  motion, 
and  perhaps,  too,  because  the  animal  substances  on  which  they  subsist, 
yielding  them  more  nutritious  particles,  from  the  same  bulk,  they  have 
need  of  less  time  for  devouring  their  food  and  providing  for  their  sub- 
sistence*. 

Sleep  is  a  state  essentially  different  from  death,  to  which  some  authors 
have  erroneously  likened  itf.  It  merely  suspends  that  portion  of  life> 
which  serves  to  keep  up  with  outward  objects  an  intercourse  necessary 
to  our  existence.  One  may  say,  that  sleep  and  waking  call  each  other, 
and  are  of  mutual  necessity.  The  organs  of  sense  and  motion,  weary  of 
acting,  rest ;  but  there  are  many  circumstances  favouring  this  cessation 
of  their  activity.  A  continual  excitation  of  the  organs  of  sense  would 
keep  them  continually  awake;  the  removal  of  the  material  causes  of  our 
sensations  tends,  therefore,  to  plunge  us  into  the  arms  of  sleep:  where- 
fore we  indulge  in  it  more  voluptuously  in  the  gloom  and  the  stillness  of 
nightj:.  Our  organs  fall  asleep  one  after  the  other;  the  smell,  the  taste, 
and  the  sight  are  already  at  rest,  when  tke  hearing  and  the  touch  still 
send  up  faint  impressions.  The  perceptions,  awhile  confused,  in  the  end 
disappear;  the  internal  senses  cease  acting;  as  well  as  the  muscles  al- 
lotted to  voluntary  motion,  whose  action  is  entirely  subject  to  that  of  the 
brain. 

*  Probably,  their  more  powerful  digestion  of  a  more  nutritious  food,  bringing  into 
the  system  a  more  sudden  accession  of  blood,  oppresses  them  with  sleep  : — a  sleep  and 
a  fullness  of  blood  required  to  recruit  the  powers  that  have  been  exhausted  by  the  la- 
borious quest  of  food,  and  by  the  long  continued  endurance  of  hunger. 

Animal  food,  according  to  the  extent  to  which  it  is  indulged  in,  or  the  length  of  the 
intervals  between  its  use,  produces  either  absolute  or  relative  vascular  plethora,  both 
which  states  dispose  to  sleep. 

•}-  To  say  that  sleep  is  the  image  of  death,  that  vegetables  sleep  always,  is  to  use  an 
inaccurate  and  unmeaning  expression.  How  can  plants,  without  brain  or  nerves,  with- 
but  organs  of  sense,  motion,  or  voice,  sleep ;  when  sleep  is  nothing  but  the  repose  of 
these  organs  ? 

t  The  tissue  of  the  eye-lids  is  not  so  opake  but  we  may  distinguish  through  them  light 
from  darkness :  accordingly,  a  lighted  torch  in  the  room,  hinders  us  from  sleeping.  For 
the  same  reason,  day  succeeding  to  night  awakens  us. 


311 

Sleep,  is  a  state,  if  not  altogether  passive,  in  which,  at  least,  the  activity 
of  most  of  the  organs,  is  remarkably  diminished,  and  that  of  some  of 
them  are  completely  suspended.  It  is  erroneously  then,  that  some  au- 
thors have  viewed  it  as  an  active  phenomenon,  and  a  function  of  the 
living  economy:  it  is  only  a  mode  or  manner  of  being.  It  is  to  no  pur- 
pose they  have  maintained,  that  to  sleep  required  some  measure  of 
strength.  Excessive  fatigue  hinders  sleep,  merely  by  a  sense  of  pain  in. 
all  the  muscles,  a  pain  that  excites  anew  the  action  of  the  brain,  which 
it  keeps  awake,  till  it  is  itself  overpowered  by  sleep. 

It  has  been  attempted  to  show  the  proximate  cause  of  sleep.  Some 
have  said  that  it  depends  on  the  collapse  of  the  lamina  of  the  cerebellum, 
which,  as  they  conceive,  are  in  a  state  of  erection  during  waking;  and 
they  argue  from  the  experiment  in  which,  by  compressing  the  cerebel- 
lum of  a  living  animal,  sleep  is  immediately  brought  on.  This  sleep, 
like  that  produced  by  compression  of  any  other  part  of  the  cerebral 
mass,  is  really  a  state  of  disease;  and  no  more  natural  than  apoplexy. 
Others,  conceiving  sleep,  no  doubt,  analogous  to  this  affection,  ascribe 
it  to  the  collection  of  humours  upon  the  brain  during  waking.  This  or- 
gan, say  they,  compressed  by  the  blood  which  obstructs  its  vessels,  falls 
into  a  state  of  real  stupor.  An  opinion  as  unsupported  as  the  other.  As 
long  as  the  humours  flow  in  abundance  towards  the  brain,  they  keep  up 
in  it  an  excitement  winch  is  altogether  unfavourable  to  sleep.  Do  we 
not  know,  that  it  is  enough  that  the  brain  be  strongly  occupied  by  its 
thoughts,  or  vividly  affected  in  anyway,  to  repel  sleep?  Coffee,  spiritu- 
ous liquors,  in  small  quantities,  will  produce  sleeplessness,  by  exciting 
the  force  of  circulation,  and  determining  towards  the  brain  a  more  con- 
siderable afflux  of  blood.  All,  on  the  other  hand,  that  may  divert  this 
fluid  towards  another  organ,  as  copious  bleedings,  pediluvium,  purges, 
digestion,  copulation,  severe  cold,  or  whatever  diminishes  the  force  with 
which  it  is  driven  towards  it,  as  inebriation,  general  debility,  tends  power- 
fully to  promote  sleep.  In  like  manner,  it  is  observed,  that  while  it  lasts, 
the  cerebral  mass  collapses:  a  sign  that  the  flow  of  blood  into  it  is  re- 
markably lessened. 

The  organs  of  the  senses,  laid  asleep,  in  succession,  awake  in  the  same 
manner.  Sounds  and  light  produce  impressions,  confused  at  first,  on  the 
eyes  and  ears;  in  a  little  time  these  sensations  grow  distinct;  we  smell, 
we  taste,  we  judge  of  bodies  by  the  touch.  The  organs  of  motion  prepare 
for  entering  into  action,  and  begin  to  act,  at  the  direction  of  the  will*. 
The  causes  of  waking  operate  by  determining  a  greater  flow  of  blood 
into  the  brain :  they  include  all  that  can  affect  the  senses,  as  the  return 
of  light  and  of  noise  with  the  rising  of  the  sun;  at  times,  they  act  within 
us.  Thus,  urine,  fecal  matter,  other  fluids  accumulated  in  their  reser- 
voirs, irritate  them,  and  send  up,  towards  the  brain,  an  agitation  which 
assists  in  dispelling  slumber.  Habit,  too,  acts  upon  this  phenomenon, 
as  on  all  those  of  the  nervous  and  sensitive  system,  with  most  remarka- 
ble influence.  There  are  many  that  sleep  soundly  amidst  noises  which, 
at  first,  kept  them  painfully  awake.  Whatever  need  he  may  have  of 
longer  repose,  a  man  that  has  fixed  the  daily  hour  of  his  awaking,  will 
awake  every  morning  to  his  hour.  It  is  as  much  under  the  controul  of 
the  will.  It  is  enough  to  will  it  strongly,  and  we  can  awake  at  any  hour 
we  choose. 

*  See  tbp  CHAPTER  on  Motion,  Art.  CLXXII. 


312 

CLXI.  Of  dreams  and  somnambulism.  Although  sleep  implies  the  per- 
fect repose  of  the  organs  of  sensation  and  of  motion,  some  of  these  or- 
gans persist  in  their  activity*;  which  obliges  us  to  acknowledge  inter- 
mediate states  between  sleep  and  waking,  real  mixed  situations,  which 
belong,  more  or  less,  to  one  or  to  the  other.  Let  us  suppose,  for  instance, 
that  the  imagination  reproduces,  in  the  brain,  sensations  it  has  formerly 
known,  the  intellect  works,  associates,  and  combines  ideas,  often  dis- 
cordant, and  sometimes  natural,  brings  forth  monsters,  horrible,  fantastic, 
or  ridiculous ;.  raises  joy,  hope,  grief,  surprise,  or  terror ;  and  all  these 
fancies,  all  these  emotions,  are  recollected  more  or  less  distinctly,  when 
we  are  again  awake,  so  as  to  allow  no  doubt  but  that  the  brain  has  been 
really  in  action,  during  the  repose  of  the  organs  of  sense  and  motion. 
Dreams  is  the  name  given  to  these  phenomena.  Sometimes  we  speak 
in  sleep,  and  this  brings  us  a  little  nearer  to  the  state  of  waking,  since 
to  the  action  of  the  brain  is  added  that  of  the  organs  of  speech.  Finally, 
all  the  relative  functions  are  capable  of  action,  excepting  the  outward 
senses.  The  brain  acts,  and  determines  the  action  of  the  organs  of  mo- 
tion or  speech,  only  in  consequence  of  former  impressions ;  and  this  state, 
which  differs  from  waking,  only  by  the  inaction  of  the  senses,  is  called 
somnambulism. 

On  this  head  we  meet  with  surprising  relations.  Somnambulists  have 
been  seen  to  get  up,  dress,  go  out  of  the  house,  opening  and  shutting 
carefully  all  the  doors,  dig,  draw  water,  hold  rational  and  connected  dis- 
course, go  to  bed  again,  and  awake  without  any  recollection  of  what 
they  had  said  and  done  in  their  sleep.  This  state  is  always  very  perilous. 
For  as  they  proceed  entirely  upon  former  impressions,  somnambulists 
have  no  warning  from  their  senses,  of  the  dangers  they  are  near.  Ac- 
cordingly, they  are  often  seen  throwing  themselves  out  at  a  window,  or 
falling  from  roofs,  on  which  they  have  got  up,  without  being  on  that  ac- 
count more  dexterous  in  balancing  themselves  there,  as  the  vulgar  believe 
in  their  fondness  for  the  marvellous. 

Sometimes,  one  organ  of  sense  remains  open  to  impression,  and  then 
you  can  direct,  at  pleasure,  the  intellectual  action.  Thus,  you  will  make 
him  that  talks  in  his  sleep,  speak  on  what  subject  you  choose,  and  steal 
from  him  the  confession  of  his  most  secret  thoughts.  This  fact  may  be 
cited  in  proof  of  the  errors  of  the  senses, "and  of  the  need  there  is  to  cor- 
rect them  by  one  another. 

The  conditions  of  the  organs  influences  the  subject  of  the  dreams.  The 
superabundance  of  the  seminal  fluid  provokes  libidinous  dreams;  those 
labouring  under  pituitary  cachexies  will  dream  of  objects  of  a  hue  like 
that  of  their  fluids.  The  hydropic  dreams  of  waters  and  fountains, 
whilst  he  who  is  suffering  with  an  inflammatory  affection,  sees  all  things 
tinged  red,  that  is,  of  the  colour  of  blood,  the  predominant  fluid. 

Difficult  digestion  disturbs  sleep.  If  the  stomach,  over-filled  with  food, 
hinders  the  falling  of  the  diaphragm,  the  chest  dilates  with  difficulty,  the 
blood,  which  flows  through  the.  lungs,  stagnates  in  the  right  cavities  of 
the  heart,  and  a  painful  sensation  comes  on,  as  if  an  enormous  weight  lay 

*  The  individual  who  even  enjoys  the  most  profound  sleep,  seldom  wakens  in  the 
same  position  as  that^in  which  he  was  at  the  moment  of  falling  asleep  :  it  is  changed 
frequently  during  the  time,  owing,  perhaps,  to  certain  obscure  sensations  giving  rise 
to  movements  analogous  to  those  of  the  foetus  in  utero,  although  more  perfect,  and 
seemingly  influenced  by  habit,  &c. 


313 

upon  the  chest,  and  were  on  the  point  of  producing  suffocation:  we  awake 
with  a  start,  to  escape  from  such  urgent  danger:  this  is  what  we  call 
night-mare,  an  affection  that  may  arise  from  other  causes,  hydrothorax, 
for  instance,  but  which  always  depends  on  the  difficult  passage  of  blood 
through  the  lungs. 

The  intellectual  faculties  which  act  in  dreams,  may  lead  us  to  certain 
orders  of  ideas,  which  we  have  not  been  able  to  compass  while  awake. 

Thus,  mathematicians  have  accomplished  in  sleep,  the  most  complex 
calculations,  and  resolved  the  most  difficult  problems.  It  is  easily  under- 
stood, how,  in  the  sleep  of  the  outward  senses,  the  sensitive  centre  must 
be  given  up  altogether  to  the  combination  of  ideas  in  which  it  must  work 
with  more  energy.  It  is  seldom  that  the  action  of  imagination  on  the 
genital  organs,  during  waking,  goes  the  length  of  producing  emission: 
nothing  is  more  common  in  sleep. 

The  human  species  is  not  the  only  one,  that  in  sleep  is  subject  to  agita- 
tions, which  are  generally  comprehended  under  the  name  of  dreams: 
they  occur  in  animals,  and  most  in  those  whose  nature  is  most  irritable 
and  sensible.  Thus,  the  clog  and  horse  dream  more  than  the  ruminating 
kinds;  the  one  barks,  and  the  other  neighs  in  sleep.  Cows  that  are 
suckling  their  calves,  utter  faint  lowings ;  bulls  and  rams  seem  goaded 
by  desires,  which  they  express  especially,  by  peculiar  motions  of  their 
lips. 

After  what  has  l^een  said  of  sleep  and  dreams,  it  will  not  be  difficult  to 
explain,  why  there  is  so  little  refreshment  of  the  powers,  from  sleep  that 
is  harassed  by  uneasy  dreams.  We  often  awake,  exceedingly  fatigued 
by  the  distress  of  imaginary  dangers,  and  the  efforts  we  have  made  to 
escape  them. 

We  have  seen  the  relations  of  man,  with  the  external  world,  esta- 
blished by  means  of  peculiar  organs,  which,  through  the  intervention  of 
the  nerves,  all  centre  in  one,  the  chief  and  essential  seat  of  the  functions 
of  which  this  chapter  treats.  As  the  phenomena  of  the  sensations  are 
brought  about  by  the  intervention  of  an  unknown  agent,  and  as  like 
those  of  electricity  and  magnetism,  they  appear  not  to  be  subject  to  the 
ordinary  laws  of  matter  and  motion,  they  have  thrown  open  the  widest 
field  to  the  conjectures  of  ignorance,  and  the  inventions  of  quackery.  It 
is  for  their  explanation,  that  the  greatest  abundance  of  theories,  and  the 
wildest,  have  been  devised. 

Ott  the  23d  of  December,  it  is  not  said  in  what  year,  a  physician  of 
Lyons,  M.  Petetin,  was  called  in  to  a  young  lady  of  nineteen,  sanguine 
and  robust.  She  was  cataleptic.  The  doctor  employed  various  reme- 
dies; and  among  others,  one  day  bethought  himself  of  pushing  over  the 
patient  on  her  pillow:  he  himself  fell  with  her,  half  stooping  upon  the 
bed,  and  this  led  him  to  the  "  discovery  of  the  transport  of  the  senses  in 
the  epigastrium,  to  the  extremities  of  the  fingers  and  of  the  toes."  I  use 
his  own  pompous  and  barbarous  expressions,  in  announcing  his  discovery. 
Our  doctor  goes  on  to  tell  with  all  gravity,  how  putting  »  bun  on  the 
epigastrium  of  the  patient,  she  perceived  the  taste,  which  was  followed 
by  motions  of  deglutition  :  if  his  word  is  to  be  taken,  hearing,  smell, 
taste,  sight,  and  touch,  were  all  there :  the  outward  senses,  being,  for 
the  time,  completely  laid  asleep.  To  give  an  air  of  credibility  to  the  mat- 
ter, he  adds,  that  she  saw  the  inside  of  her  body,  guessed  what  was  in 
the  pockets  of  bystanders,  made  no  mistake  in  the  money  in  their  purses; 
but  the  miracle  was  over,  the  moment  they  lapped  the  objects  in  a  silk 

2R 


314 

stuff,  a  coat  of  wax,  or  interposed  any  other  non-conductor.  Finally, 
to  put  to  proof  the  wfcole  power  of  faith  in  his  readers,  M.  Petetin  ex- 
claims, «  Oh  prodigy  beyond  conception  !  was  a  thought  formed  in  the 
brain  without  any  sign  of  it  in  words,  the  patient  was  instantly  acquaint- 
ed with  it"*.  Further  details  of  so  incredible  a  story  would  be  altoge- 
ther superfluous. 

I  should  not  have  disturbed  the  book  of  M.  Petetin,  from  its  peaceful 
slumber,  among  the  innumerable  pamphlets  which  Mesmerism  has 
brought  into  the  world,  if  a  writer  on  physiology  had  not  been  the  dupe 
of  this  mystification,  and  had  not  proceeded  from  it,  to  write  a  long  chap- 
ter on  the  metastases  of  sensibility. 

If  we  should  be  so  unfortunate  as  to  be  reproached  by  the  lovers  of  the 
marvellous,  with  pushing  scepticism  too  far,  we  must  make  answer,  that 
M.  Petetin  is  the  sole  witness  of  his  miracle  ;  that  it  is  impossible,  from 
his  relation,  to  know  when  or  on  whom  the  prodigy  took  place  5  and  that 
this  zealot  of  magnetism  might  have  invented  this  story  to  confound  the 
unbelievers  who  ventured  to  turn  into  ridicule,  his  system  of  electricity 
and  of  the  human  bodv. 


CHAPTER    VIII. 

OF  MOTION. 


CLXII.  THIS  Chapter  will  treat  only  of  the  motions  performed  by  the 
muscles  under  the  influence  of  the  will ;  they  are  called  muscles  of  loco- 
motion, as  it  is  by  means  of  them,  that  the  body  changes  its  situation, 
moves  from  one  spot  to  another,  a\oicls  or  seeks  surrounding  objects, 
draws  them  towards  itself,  grasps  them,  or  repels  them.  The  internal, 
involuntary,  and  organic  motions,  by  means  of  which  each  function  is  per- 
formed, have  already  been  investigated  separately. 

The  organs  of  motion  may  be  distinguished  into  active  and  fiassajj&  the 
former  are  the  muscles,  the  latter  the  bones,  and  all  the  parts  by  which 
they  are  articulated.  In  fact,  when  in  consequence  of  an  impression  re- 
ceived by  the  organs  of  sense,  we  wish  to  approach  towards  the  object 
that  produced  it,  or  to  withdraw  from  it,  the  muscular  organs,  called  in- 
to action  by  the  brain,  contract  $  while  the  bones,  which  obey  this  action, 
perform  only  a  secondary  part,  are  passive,  and  may  be  looked  upon  as 
levers  absolutely  inert. 

The  muscles  consist  of  bundles  of  fibres,  always,  to  a  certain  degree, 
red  in  man :  ihis  colour,  however,  is  not  essential  to  them,  since  it  may 
be  removed,  and  the  muscular  tissue  blanched  by  maceration,  or  by  re- 
peated washing. 

Whatever  may  be  the  situation,  the  length,  the  breadth,  the  thickness, 
the  form,  or  the  direction  of  a  muscle,  it  is  formed  of  a  collection  of  se- 


*  Electricite  animate,  1  vol.  8vo.  Lyon,  81 


315 

veral  fasciculi  of  fibres,  enveloped  in  a  cellular  sheath  similar  to  that 
which  covers  the  muscle  itself,  and  separates  it  from  the  surrounding 
parts.  Each  fasciculus  is  formed  of  the  union  of  a  multitude  of  fibres, 
so  delicate,  that  anatomy  cannot  reduce  them  to  their  ultimate  division, 
and  that  the  smallest  distinguishable  fibre  is  still  formed  by  the  juxta  po- 
sition of  numerous  fibrilhe  of  incalculable  minuteness.  As  the  last  divi- 
sions of  the  muscular  fibre  completely  elude  our  means  of  investigation, 
it  would  be  very  absurd  to  attempt  to  explain  their  minute  structure,  and, 
after  the  example  of  Muys,  to  write  a  voluminous  work  on  this  obscure 
part  of  physiology.  Shall  we  say,  with  the  above  author,  that  each  dis- 
tinguishable fibre  is  composed  of  three  fibrillse  progressively  decreasing 
in  size;  with  Leeuwenhoek,  that  the  diameter  of  this  elementary  fibre  is 
only  the  hundred  thousandth  part  of  a  grain  of  sand ;  with  Swamrfter- 
dam,  de  Heyde,  Cowper,  Ruysch,  and  Borelli,  that  this  primitive  fibre 
consists  of  a  series  of  globular,  rhomboidal  molecules;  with  Lecat,  that 
it  is  nervous;  with  Vieussens  and  Willis,  that  it  is  formed  by  the  extreme 
ramifications  of  arteries;  with  others,  that  it  is  cellular,  tomeritous,  8cc. 
How  is  it  possible  to  speak,  with  any  degree  of  certainty,  of  the  nature 
of  the  parts  of  a  whole,  which,  from  its  extreme  minuteness,  eludes  our 
most  accurate  investigations.  To  explain  the  phenomena  of  muscular 
action,  it  is  inefficient  to  conceive  each  fibre  as  formed  of  a  series  of  mo- 
lecules of  a  peculiar  nature,  united  together  by  some  unknown  medium, 
whether  that  be  oil,  gluten,  or  any  other  substance,  but  whose  cohesion 
is  manifestly  kept  up  by  the  vital  power,  since  the  muscles  yield,  after 
death,  to  efforts  by  which,  during  life,  they  would  not  have  been  torn  5 
and  such  is  their  tenacity,  that  they  are  very  seldom  ruptured*. 

These  fibres,  which,  when  irritated,  possess,  in  the  highest  degree,  the 
power  of  shortening  themselves — of  contracting,  however  minute  one  may 
suppose  them,  are  supplied  with  vessels  and  nerves.  In  fact,  though  they 
are  neither  vascular  nor  nervous,  as  may  be  readily  ascertained  by  com- 
paring the  vessels  and  nerves  which  enter  into  the  structure  of  the  mus- 
cles, with  that  of  these  organs,  and  by  attending  to  the  difference  of  their 
properties;  each  fibre  receives^  the  power  of  contracting,  from  the  blood 
brought  to  it  by  the  arteries,  and  from  the  fluid  transmitted  from  the 
brain,  along  the  nerves.  A  cellular  sheath  surrounds  these  fibrillae  (and 
the  nerves  and  vessels  perhaps  terminate  within  it)f,  others  unite  them 

*  "  M.  BATTEH,  by  the  assistance  of  his  powerful  microscope,  discovered  muscular 
fibres  to  be  chains  of  globules,  and  he  conceived  that  they  may  be  constructed  from  the 
globules  of  fibrine  arranged  in  lines.  —  Copland. 

\  The  majority  of  anatomists  suppose  that  the  muscular  fibre  itself  is  beyond  the 
circuit  of  the  circulation,  and  this  appears  in  some  points  of  view  the  correct  opinion,  if 
we  attend  to  the  form  and  size  of  the  fibres,  and  to  their  connexions  with  the  cellular 
tissue ;  but  although  we  may  grant  that  the  red  globules  of  the  blood  do  not  circulate 
through  the  muscular  fibres  themselves,  and  that  these  globules  pervade  only  the  capil- 
laries of  the  connecting  cellular  substance,  still  we  must  allow  that  they  are  formed  and 
afterwards  supported,  either  by  the  vessels  conveying  red  blood,  assimilation  taking 
place,  in  the  manner  of  a  deposit  from  them,  without  any  continuity  of  texture,  or  by 
the  medium  of  a  direct  communication  and  admixture  of  a  particular  series  of  capillary 
terminations  of  vessels  with  the  muscular  fibres,  into  which  the  red  globules  cannot 
enter  owing  to  the  great  tenuity  of  these  capillaries.  If  we  choose  the  former  alter- 
native, which  appears,  however,  the  least  probable,  we  may  conceive  that  the  nervous 
terminations,  in  muscular  parts,  soften  into  an  invisible  pulp,  and  unite  intimately  with 
the  capillary  vessels,  and  with  the  cellular  texture,  which  connects  the  individual  fibres; 
and  that  the  chain  of  globules,  of  which  the  fibres  are  composed,  being  acted  on  by  the 
influence  resulting  from  the  action  of  the  nervous  on  the  vascular  terminations  in  the 


316 

together ;  the  fasciculi  of  fibres  are  inclosed  in  common  sheaths,  and 
these  unite,  in  the  same  manner,  into  masses  varying  in  size,  and  the 
union  of  which  forms  the  muscles;  fat  seldom  accumulates  in  the  cellu- 
lar tissue  which  connects  together  the  smallest  fasciculi;  it  collects,  in 
small  quantity,  in  the  interstices  of  the  more  considerable  fasciculi;  last- 
ly, it  is  in  rather  greater  quantity,  around  the  muscle  itself.  A  lympha- 
tic and  aqueous  vapour  fills  these  cells,  maintains  the  suppleness  of  the 
tissue,  and  promotes  the  action  of  the  organ,  which  a  fluid  01  more  con- 
sistence would  have  impeded. 

The  greater  number  of  muscles  terminate  in  bodies,  in  general  round, 
of  a  brilliant  white  colour,  that  forms  a  striking  contrast  with  the  red  co- 
lour of  the  muscular  flesh,  in  which  one  of  their  extremities  is  imbedded, 
while  the  other  extremity  is  attached  to  the  bone  and  is  lost  in  the  peri- 
osteum, though  the  tendons  are  quite  distinct  from  it.  The  tendons  are 
formed  by  a  collection  of  longitudinal  and  parallel  fibres  ;  their  structure 
is  more  compact  than  that  of  the  muscles,  they  are  harder  and  apparently 
receive  neither  nerves  nor  vessels;  they  consequently  possess  but  a  very 
inferior  degree  of  vitality;  hence  they  are  frequently  ruptured  by  the  ac- 
tion of  the  muscles.  The  muscular  fibres  are  implanted  on  the  surface  of 
the  tendinous  cords,  without  being  continuous  with  the  filaments  forming 
the  latter;  they  join  them  in  a  different  manner,  and  at  angles  more  or 
less  obtuse. 

The  tendons,  in  penetrating  into  the  fleshy  part  of  the  muscles,  expand, 
become  thinner,  and  form  thus  the  internal  aponeuroses.  The  external 
aponeuroses,  independent  of  the  tendons,  though  the  same  in  structure, 
differ  from  them  only  in  the  thinness  and  greater  surface  of  the  planes 
formed  by  their  fibres.  At  one  time,  they  cover  a  portion  of  the  muscle 
to  which  they  belong;  at  another,  they  surround  the  whole  limb,  furnish- 
ing points  of  insertion  to  the  muscles;  they  prevent  the  muscles  and  their 
tendinous  cords  from  being  displaced;  in  a  manner,  direct  their  action, 
and  increase  their  power,  in  the  same  way  as  a  moderately  tight  girdle 
adds  to  the  power  of  an  athletic. 


enveloping  cellular  snbstance,  experience  in  consequence  a  contraction  in  proportion 
to  the  nervous  excitement.  In  this  case  we  must  suppose  a  certain  influence  to  emanate 
from  the  connecting  medium  to  the  muscular  fibre,  without  any  other  communication 
than  that  of  contact  or  contiguity.  If,  on  the  other  hand,  we  adopt  the  latter  alternative, 
and  believe  that  an  order  of  capillary  vessels  of  great  tenuity  enter  into  the  structure 
of  the  muscular  fibre,  and  that  the  voluntary  and  organic  nerves  which  blend  with  the 
capillary  vessels  also  proceed  to,  and  terminate  in  this  structure,  we  may  further  con- 
clude— and,  indeed,  the  conclusion  will  necessarily  follow, — that  the  muscular  fibre  is 
composed  of  a  certain  order  of  capillary  vessels,  and  of  the  terminations  of  the  ganglial 
nerves  (which  nerves  we  must  suppose  to  supply,  and  to  terminate  with  these  capilla- 
ries, as  they  are  found  to  envelope,  and  to  be  distributed  to  the  muscular  and  internal 
coats  of  the  larger  ramifications  or  trunks  of  the  vessels  whence  the  capillaries  are  sent 
off)  with  the  extremities  of  voluntary  nerves  which  are  so  abundantly  supplied  to  mus- 
cular parts.  Having  considered  that  the  muscular  fibre  is  formed  from  this  combination, 
me  have  not  data  whence  we  can  farther  infer  its  intimate  nature,  or  the  extent  to 
which  each  of  these  systems  contributes  to  its  formation  in  the  voluntary  muscles.  We 
may  suppose,  however,  that  the  functions  of  these  textures  differ  according  as  either  of 
the  constituents  which  we  have  now  assigned  them  predominate  in  their  constitution, 
(see  Note  at  p.  17.)  The  observations  of  Mr.  Bauer,  we  may  state,  seem  to  support  the 
view  we  have  now  offered. —  Copland. 

See  APPENDIX,  Note  F  F,  for  further  observations  on  this  subject,  and  on  Irrita- 
bility. 


.317 

We  cannot  admit,  with  Pouteau,  that  the  muscles  of  the  limbs,  though 
applied  to  the  bones  by  aponeurotic  coverings,  can  become  displaced,  so 
as  to  form  herniae.  When  they  contract  in  a  wrong1  position,  some  fib- 
rillce  are  torn,  and  this  gives  rise  to  most  of  those  momentary  and  very 
sharp  pains  called  cramp.  I  have,  at  present,  before  me,  the  case  of  a 
young  girl,  in  whom  the  aponeurosis  of  the  leg,  exposed  in  conse- 
quence of  an  extensive  ulceration,  exfoliated  from  the  middle  and  fore 
part  of  the  limb  to  the  instep.  This  exfoliation  was  accompanied  by  a 
displacement  of  the  tibialis  anticus  of  the  extensors  of  the  toes;  the  leg 
is  become  deformed,  the  motions  of  extension  of  the  foot  and  toes  are  per- 
formed with  difficulty,  and  will  soon  become  impossible,  when  the  exfoli- 
ation of  the  tendons  follows  that  of  the  aponeurosis  which  protected  them 
from  the  air. 

CLXIII.  When  a  muscle  contracts,  its  fibres  are  corrugated  trans- 
versely, its  extremities  are  brought  nearer  to  each  other,  then  recede,  and 
again  approach  towards  one  another.  These  undulatory  oscillations, 
which  are  very  rapid,  are  followed  by  a  slighter  degree  of  agitation  ;  the 
body  of  the  muscle,  swollen  and  hardened  in  its  decurtation,  has  acted  on 
the  tendon  in  which  it  terminates ;  the  bone  to  which  the  latter  is  connect- 
ed is  set  in  motion,  unless  other  agents,  more  powerful  than  the  muscle 
which  is  in  action,  prevent  its  yielding  to  that  impulse.  Such  are  the 
phenomena  exhibited  by  the  muscles  exposed  in  a  living  animal  or  in 
man,  when  their  contractions  are  brought  on  by  the  application  of  a  sti- 
mulus. But  these  contractions,  determined  by  external  causes,  are  never 
so  strong  or  instantaneous,  as  those  which  are  determined  by  the  will,  in 
a  powerful  arid  sudden  manner.  When  an  athletic  man  reduced  by  ill- 
ness, powerfully  contracts  the  biceps  muscle  of  the  arm,  this  muscle  is 
seen  to  swell  suddenly,  to  stiffen  and  to  continue  motionless  in  that  state 
of  contraction,  as  long  as  the  cerebral  influence,  or  the  act  of  the  will, 
which  determines  it,  lasts. 

Though  the  muscles  manifestly  swell  in  contracting,  and  though  the 
limbs  are  confined  by  the  ligatures  applied  round  them,  the  whole  bulk 
of  the  contractile  organ  diminishes:  it  loses  in  length,  more  than  it  gains 
in  thickness  This  is  proved  by  Glisson's  experiment  which  consists  in 
immersing  the  arm  in  a  vessel  filled  with  a  fluid,  which  sinks  when  the 
muscles  act.  We  cannot,  however,  estimate  the  diminution  of  bulk,  by 
the  degree  in  which  the  fluid  sinks,  since  that  effect  is,  in  part,  owing  to 
the  collapse  of  the  layers  of  the  adipose  tissue,  which  is  compressed  in  the 
muscular  interstices. 

A  sound  state  of  the  vessels  and  nerves  distributed  to  muscles  is  indis- 
pensible  to  their  contraction.  If  the  free  circulation  of  the  blood  or  of 
the  nervous  fluid  is  prevented,  by  tying  the  arteries  or  nerves  ;  if  the  re- 
turn of  the  blood,  along  the  veins,  is  prevented,  by  applying  a  ligature  to 
these  vessels,  the  muscles  will  be  completely  palsied.  By  dividing  or  ty- 
ing the  nerves,  the  action  of  the  muscles  to  which  they  are  distributed, 
is  suddenly  interrupted.  The  same  effect  may  be  produced  by  intercept- 
ing the  course  of  the  arterial  blood,  though  in  a  less  rapid  and  instanta- 
neous manner;  and  it  is  very  remarkable,  that  it  is  equally  necessary  that 
the  veins  should  be  as  sound  as  the  arteries,  to  enable  muscular  action  to 
take  place.  Kaaw  Boerhaave  ascertained,  by  actual  experiment,  that  when 
a  ligature  is  applied  to  the  vena  cava,  above  the  lilacs,  paralysis  of 
the  lower  extremities  is  brought  on,  as  when  the  aorta  is  tied,  as  was 


318 

done  by  Steno  in  the  same  situation*.  And  this  is  a  further  proof  of  what 
we  have  said  elsewhere,  of  the  stupifying  qualities  of  the  blood  which 
flows  in  the  veins. 

The  irritability  of  the  muscles  destined  to  voluntary  motions  is  propor- 
tioned to  the  size  and  number  of  the  nerves  and  arteries  which  are 
distributed  to  their  tissuef.  The  tongue,  which  of  all  the  contractile 
organs  receives  the  greatest  number  of  cerebral  nerves,  is,  likewise,  that 
which,  of  all  those  under  the  controul  of  the  will,  has  most  extent,  most 
freedom,  and  most  variety  of  motions!.  The  muscles  of  the  larynx,  and 
the  intercostals,  receive  nearly  as  many,  considering  the  smallness  of 
these  parts§. 

CLXIV.  Of  all  the  hypothesis  applied  to  the  explanation  of  the  phe- 
nomena of  muscular  contraction,  that  appears  to  me  the  most  ingenious 
and  the  most  probable,  which  makes  it  to  depend  on  the  combinations 
of  hydrogen,  of  carbon,  of  azote,  and  other  combustible  substances  in 
the  fleshy  part  of  the  muscle,  with  the  oxygen  conveyed  with  the  blood 
by  the  arteries. 

To  effect  this  combination,  it  is  necessary,  not  only  that  the  muscle  be 
supplied  with  arterial  blood,  and  that  oxygen  come  in  contact  with  the 
substances  which  it  is  tooxydize,  but  it  is  required,  that  a  stream  of  nerv- 
ous fluid  should  penetrate  through  the  tissue  of  the  muscle,  and  determine 
the  decompositions  which  take  place,  as  the  electrical  spark  gives  rise  to 
formation  of  water  by  the  combination  of  the  two  gases  of  which  it  con- 
sists. According  to  this  theory,  first  proposed  by  Girtanner,  all  the 
changes  which  take  place,  during  the  contraction  of  a  muscle,  theturges- 
cence,  the  decurtation  and  the  induration  of  its  tissue,  its  change  of  tem- 
perature depend  on  this  reciprocal  action  of  the  elements  of  the  muscular 
fibre,  and  of  the  oxygen  of  arterial  blood. 

Muscular  flesh  is  harder,  firmer,  and  more  oxydized,  according  as  the 
animaltakes  much  exercise.  We  well  know,  what  a  difference  there  is, 
between  the  flesh  of  wild  and  of  the  domestic  animals  ;  between  the  flesh 
of  our  common  fowl  and  that  of  birds  accustomed  to  remain  long  on  the 


*  Ligature  of  the  aorta  may  be  conceived  to  produce  paralysis,  owing  chiefly  to  the 
stop  it  puts  to  the  circulation  of  arterial  blood  in  that  part  of  the  spinal  cord,  and  in  the 
neurilema  of  the  nerves,  below  where  the  ligature  is  placed. 

I  See  APPENDIX,  Note  F  F. 

$  It  is  scarcely  necessary  to  repeat,  that  I  am  not  speaking  of  those  motions,  more  or 
less  involuntary,  performed  by  muscles  which  receive  tiie  nerves,  in  part  or  wholly, 
from  the  great  sympathetics.  Though  the  particular  nature  of  these  nerves  has  a  re- 
markable influence  on  the  organs  to  which  they  are  distributed,  we  find  that  the  general 
rule  is  almost  without  exception,  for  the  heart  and  diaphragm  which  hold  the  first  rank 
among  the  parts  endowed  with  irratibility,  receive  a  considerable  number  of  vessels  and 
nerves. — Authur's  Note. 

§  The  disposition  of  the  muscles  to  contract  is  different  from,  and  even  opposite  to, 
their  energy  of  contraction.  The  feeble  muscles  of  an  hysterical  female  contract  so 
readily  and"  so  frequently  from  the  slightest  irritation,  as  nearly  to  appear  involuntary 
in  their  actions ;  while,  on  the  contrary,  the  powerful  muscles  of  the  athlet  act  only 
from  energetic  stimuli  and  from  fully  expressed  volition.  Thus  we  observe  in  feeble  in- 
dividuals  a  certain  mobility  of  muscular  parts  and  organs,  which  does  not  exist  in  the 
robust,  as  if  the  irritability  of  such  parts  were  excited  with  a  facility  in  proportion  to 
the  deficiency  of  energetic  action.  The  disposition  of  muscles  to  contract  differs  also 
according  to  the  age  of  the  animal,  and  it  bears  even  some  relation  to  organization  of 
the  muscle  itself. —  Copland. 

See  APPENDIX,  Note  F  F,  for  remarks  on  the  period  at  which  the  voluntary  muscles 
are  formed,  find  on  their  appearances  and  constitution,  at  the  different  periods  of  life. 


319 

wing;  in  the  former,  it  is  white,  tender  and  delicate,  while,  in  the  latter, 
it  is  tough,  stringy,  dark-coloured,  carbonaceous,  and  of  a  very  strong- 
smell.  Respiration,  of  which  the  principal  use  is  to  impregnate  arterial 
blood*  with  the  oxygen  necessary  to  the  contractions  of  the  muscular 
fibre,  is  more  complete,  decomposes  the  greater  quantity  of  atmospheri- 
cal air,  in  those  animals  that  are  naturally  destined  to  most  exertion. 
Those  birds  which  support  themselves  in  the  air  by  powerful  and  fre- 
quent motions,  have  likewise,  the  most  active  respiration.  Athletes,  who 
astonish  us  by  the  developement  of  their  muscular  organs,  and  by  the 
powerful  efforts  of  which  they  are  capable,  all  have  a  very  ample  chest, 
a  powerful  voice,  and  very  capacious  lungsf.  In  running,  as  there  is  a 
considerable  consumption  of  the  principle  of  motion,  we  pant,  that  is, 
we  breathe  in  a  hurried  manner,  that  there  may  be  the.  greatest  possible 
quantity  of  blood  oxydized  to  perform  the  contractions  necessary  to  the 
exercise  of  running. 

CLXV.  Of  the  preponderance  of  the  flexors  over  the  extensors\.  The  ex- 
tensor muscles  are,  generally,  weaker  than  the  flexors;  hence  the  most 
natural  position,  that  in  which  all  the  powers  are  naturally  in  equilibrio, 
that  which  our  limbs  assume  during  sleep,  when  the  will  ceases  to  deter- 
mine the  vital  influx  to  the  parts  under  its  controul,  that  in  which  we  can 
continue  longest  without  fatigue,  is  a  medium  between  flexion  and  exten- 
sion, a  real  state  of  semi-flexion. 

Attempts  have  been  made  to  discover  the  cause  of  this  preponderance 
of  the  flexor  muscles  over  their  antagonists.  According  to  Borelli,  the 
flexors  being  shorter  than  the  extensors  of  the  same  articulation,  and  con- 
tracting equally^,  the  former  must  occasion  a  more  extensive  motion  of 
the  limbs,  and  determine  them  towards  a  state  of  flexion.  But  it  is,  in 
the  first  place,  incorrect  to  say,  that  the  flexors  are  shorter  than  the  ex- 
tensors; and,  in  the  next  place,  if  we  are  to  estimate,  by  the  length  of  a 
muscle,  the  extent  of  motion  that  may  be  produced  by  its  action,  we  ought 
not  to  measure  the  whole  of  the  fleshy  part,  nor  to  include  in  the  calcula- 
tion, the  tendinous  cord  which  terminates  it,  but  UTconsider  the  length 
of  its  fibres,  on  which  depends  entirely  the  extent  of  motion  produced  by 
its  contractions. 

The  degree  of  decurtation  of  which  a  muscle  is  capable,  is  always  pro- 
portioned to  the  length  of  its  fleshy  fibres,  as  is  the  power  of  contraction 
to  the  number  of  the  fibres.  Now,  if  the  fibres  of  the  flexors  are  in  greater 
number  than  those  of  the  extensors,  it  follows  as  a  necessary  conse- 
quence, that  the  limbs  will  be  brought  into  a  state  of  flexion,  when 
the  principle  of  motion  shall  be  distributed  to  them  in  an  equal  quantity^ 
and  even  though  the  number  of  fibres  should  be  the  same  in  the  flex- 


*  See  APPENDIX,  Note  W. 

f  I  never  saw  a  very  strong1  man  that  had  not  broad  shoulders,  which  indicates  a  con- 
siderable developement  of  the  cavity  of  respiration.  If  there  be  individuals  that  seem 
to  be  exceptions  to  this  general  law,  it  is  that  by  frequent  exercise,  and  by  a  laborious 
life,  they  have  increased  the  natural  power  of  their  muscles.  This  increase  is  seldom 
universal,  but  almost  always  limited  to  certain  parts  which  have  been  most  employed ; 
as  the  arms,  the  legs,  or  the  shoulders. — Author's  Note. 

t  The  theory  of  the  preponderance  of  the  flexors  is  entirely  my  own,  and  was  first 
proposed  by  me,  in  the  collection  of  Memoirs  of  the  Medical  Society  of  Paris,  for  the 
year  VII.  of  the  Republic  (1799.)— Author's  JVote. 

§  Musculi  flexores  ejusdem  articuli  breviores  sunt  extensoribus,  et  utrique  jcque  con- 
trabuntur  Prop.  180,  de  motu  animalium. 


320 

ftrs  and  extensors,  the  limbs  would  still  be  in  a  state  of  flexion,  if  the 
fibres  of  the  former  being  longer,  they  made  the  parts  move  through  a 
greater  space. 

*tf  we  examine  the  different  parts  of  the  body,  the  articulations  of  the 
limbs,  and  especially  of  the  knee,  the  knowledge  of  which  is  of  the  high- 
est importance  in  understanding  the  theory  of  standing,  it  will  be  seen 
that  the  flexor  muscles  exceed  the  extensors,  in  the  number  and  length 
of  their  fleshy  fibres.  If  we  compare  the  biceps  cruris,  the  semi  tendi- 
nosus,  the  serni  membranosus,the  rcctus  internus,  the  sartorius,  the  ge- 
melli,  the  plantaris,  and  the  popliteus,  which  all  concur  in  the  flexion  of 
the  leg,  to  the  triceps  cruris  and  to  the  rectus,  which  extend  the  leg,  we 
shall  readily  understand  that  the  fibres  of  these  last  are  much  shorter,  and 
in  smaller  number.  Those  of  the  sartorius  and  rectus  internus  are  the 
longest  of  all  the  muscles  employed  in  voluntary  motion ;  the  fibres  of 
the  posterior  muscles  of  the  limb  are  not  inferior  in  length  to  the  fibres 
of  the  muscles  at  the  fore  part. 

Besides,  the  flexor  muscles  are  inserted  into  the  bones  which  they  are 
to  move  farther  from  their  centre  of  motion.  In  fact,  if  the  insertion  of 
the  semi  membranosus  is  situated  nearly  at  the  same  height,  the  sartorius, 
the  rectus  internus,  the  semi  tendinosus,  the  biceps,  and  the  popliteus, 
are  inserted  lower  than  the  extensors  of  the  leg.  But  this  difference  is 
particularly  observable  in  the  plantaris  and  gemelli,  which  terminate  at 
the  greatest  possible  distance  from  the  centre  of  motion,  and  which  act 
with  a  very  long  lever*;  lastly  most  of  these  muscles  depart  much  more 
than  the  extensors,  from  a  parallel  direction  to  the  bones  of  the  leg.  We 
all  know  the  curved  line  of  the  course  of  the  sartorius,  of  the  rectus  in- 
ternus, and  semi  tendinosus,  by  which  the  angle  of  their  insertion  becomes 
more  favourable. 

The  flexor  muscles  which,  on  their  being  first  called  into  action,  are 
nearly  parallel  to  the  levers  which  they  are  to  move,  tend  to  become 
perpendicular  to  them,  in  proportion  as  the  motion  of  flexon  is  carried  on. 
Thus,  the  brachialis,  the  biceps  brachii,  and  the  supinator  longus,  the 
main  line  of  direction  of  which  is  nearly  parallel  to  that  of  the  bones  of 
the  fore  arm,  when  the  flexion  of  this  limb  commences,  become  oblique, 
then  perpendicular  to  this  bone,  and  at  last  form  with  it  the  angle  most 
favourable  their  action.  The  same  applies  to  the  flexors  of  the  leg;  the 
angle  of  their  insertion  becomes  greater  the  more  it  bends  on  the  thigh. 
The  extensors,  on  the  contrary,  are  in  the  most  favourable  state  for  ac- 
tion, at  the  moment  when  their  contraction  begins,  in  proportion  as  the  ex- 
tension goes  on,  they  have  a  tendency  to  become  parallel  to  the  levers 
which  they  sei  in  motion;  their  action  even  ceases  before  the  parallelism 
is  complete,  at  the  elbow  by  the  resistance  of  the  olecranon,  and  at  the 
knee  by  the  numerous  ligaments  and  by  the  tendons  situated  towards  the 
posterior  part  of  the  articulation. 

The  flexor  muscles  have,  therefore,  fibres  of  greater  length  and  more 
numerous  than  those  of  the  extensors.  They  are  inserted  into  the  bones, 


*  We  may,  in  this  respect,  compare  the  gemelli  to  the  supinator  longus,  the  use  of 
which  is  not  limited,  as  was  shown  by  Heister,  to  the  supination  of  the  hand ;  but  which 
is,  likewise,  a  flexor  of  the  fore  arm,  and  acts  the  more  powerfully,  as  its  inferior  insertion 
is  at  a  greater  distance  from  the  elbow  joint,  and  as  its  fibres  are  the  longest  of  all  those, 
of  the  muscles  of  the  upper  extremity.— Copland, 


321- 

at  a  greater  distance  from  the  centre  of  their  motion,  at  an  angle  less 
acute,  and  which  increases  in  size,  as  the  limbs  bend.  The  union  of 
these  causes  gives  to  the  limbs  their  superior  power,  and  the  greater 
range  of  motion  in  these  muscles,  is  a  consequence  of  the  arrangement 
of  the  articulating  surfaces,  which  almost  all  incline  towards  the  side  of 
flexion. 

This  preponderance  of  the  flexor  muscles,  varies  according  to  the  dif- 
ferent periods  of  life ;  in  the  foetus,  the  parts  are  all  bent  very  consider- 
ably; this  convolution  of  the  young  animal  may  be  perceived  from  the 
earliest  period  of  gestation,  when  the  embryo,  of  the  size  of  a  French 
bean,  and  suspended  by  the  umbilical  cord,  floats  in  the  midst  of  the  liquor 
amnii,  in  a  cavity  of  which  it  is  more  and  more  confined,  as  it  approaches 
to  the  period  of  its  birth.  This  excessive  flexion  of  the  parts,  which  was 
required  to  enable  the  produce  of  conception  to  accomodate  itself  to  the 
elliptical  shape  of  the  uterus,  concurs  in  giving  to  the  muscles  which  pro- 
duce it,  the  superiority  which  they  retain  during  the  remainder  of  their 
life.  The  new-born  child  preserves,  in  a  very  remarkable  manner,  the 
habits  of  gestation ;  but,  in  proportion  as  it  grows,  it  straightens  its  body, 
and,  by  frequent  attempts  to  stretch  itself,  shows  that  a  just  proportion  is 
about  to  take  place  between  the  muscular  powers.  When  the  child  be- 
comes capable  of  standing  erect,  abandoned  to  its  own  powers,  all  its  parts 
are  in  a  state  of  semi  flexion,  it  staggers  and  is  unsteady  on  its  feet.  To- 
wards the  middle  of  life,  the  preponderance  of  the  flexors  over  the  ex- 
tensors, becomes  less  apparent;  a  man  enjoys  fully  and  completely  his 
power  and  locomotion;  but,  as  he  advances  in  years,  this  power  forsakes 
him;  the  extensor  muscles  gradually  return  to  the  state  of  comparative 
debility  of  infancy,  and  become  incapable  of  supporting  the  body,  in  a 
fixed  and  permanent  manner. 

CLXVI.  The  state  of  our  limbs,  during  sleep,  approaches  to  that  of 
the  foetus,  which  according  to  Buffon,  may  be  considered  to  be  in  a  pro- 
found slumber.  The  cessation  of  sleep  is  attended  in  man,  as  well  as  in 
most  animals,  by  frequent  stretchings.  We  extend  our  limbs  forcibly, 
to  give  to  the  extensors,  the  tone  which  they  require  during  the  state 
of  waking*. — Barthez  accounts,  in  the  same  way,  for  the  manner  in 
which  the  cock  announces  his  waking,  by  crowing  and  flapping  his 
wings. 

It  may  happen  in  consequence  of  a  morbid  determination  of  the  vital 
principle,  that  our  limbs  may  remain  in  a  state  of  extension  during  sleep. 
Hence  Hippocrates  recommends,  that  the  state  of  the  limbs  be  carefully 
attended  to,  while  the  patient  sleeps,  for,  as  he  observes,  the  farther  that 
condition  is  from  the  natural  state,  the  greater  the  danger  to  be  appre- 
hended of  the  patient's  life.  In  certain  nervous  diseases  characterized 
by  a  manifest  aberration  in  the  distribution  of  the  vital  power,  a  continued 
state  of  extension  must  be  considered  a  symptom  highly  dangerous ;  I 
have  had  several  times  occasion  to  observe,  that  in  cases  of  wounds  at- 
tended with  convulsions  and  tetanus,  these  alarming  affections  were  an- 
nounced by  the  permanent  extension  of  the  limbs  during  sleep,  before  a 


*  Haller  thinks,  that  these  extensions  are  intended  to  relieve  the  uneasy  sensations 
occasioned  by  a  long  continued  flexion,  J\nnc  quidem  homines  et  animalia  extendunt  artus 
quodiis  fere  con/lexis  dormiant,  etex  eo  pei^petuo  situ,  in  musculis  sensus  incommodes  oriatur, 
quern  extensione  t ollunt,  (phenomena  ejcpergiscentium,}  Elementa-physiologx,  torn.  V.  p.  621, 

2  S 


322 

difficulty  of  moving  the  jaw  could  give  rise  to  any  apprehension  of  their 
approach. 

Disease  and  excesses  of  all  kinds,  occasion  in  the  extensor  muscles  a 
relative  weakness  that  is  very  remarkable,  hence  we  see  convalescents,  and 
those  who  have  been  addicted  to  voluptuousness,  walk  with  bending  knees, 
the  more  so  as  their  debility  is  greater,  and  as  the  force  of  the  extensors 
is  more  completely  exhausted.  The  flexion  of  the  knees  is  then  limited 
by  that  condition  in  which  the  tendons  of  the  extensors  of  the  leg  acton 
the  tibia,  at  an  angle  sufficiently  great  to  make  up  for  their  diminished 
energy.  There  exists  a  condition  of  the  animal  economy,  in  which  all 
the  muscular  organs  appear  wearied  with  exertion,  and  the  limbs  assume 
indifferently  any  position.  In  this  state,  which  is  always  a  very  serious  one, 
as  it'indicates  an  almost  complete  want  of  action  in  a  system  of  organs 
whose  functions  are  absolutely  essential  to  life,  a  state  to  which  physici- 
ans have  given  the  name  of  prostration*,  the  limbs  if  unsupported,  fall  of 
their  own  weight,  as  if  they  were  palsied;  the  trunk  is  motionless,  and 
supine.  The  patient  is  incapable  of  changing  his  attitude,  and  yielding 
to  the  weight  of  his  body,  sinks  on  the  inclined  plane  formed  by  the  bed, 
and  seems  very  heavy  to  those  who  may  attempt  to  raise  him,  because 
from  his  helplessness,  he  requires  to  be  moved  as  an  inert  substance. 


*  It  is  from  a  knowledge  of  the  strength  of  his  patient,  that  the  physician,  in  the  treat- 
ment of  disease,  deduces  the  most  instructive  indications.  It  seems  to  me,  that  we  ought 
to  endeavour  to  characterize,  by  specific  terms,  the  different  states  of  animal  adynamia 
in  different  diseases.  Our  language,  less  fruitful  in  imagery  than  the  ancient  languages, 
will  not  easily  furnish  these  characteristic  denominations,  so  useful  in  a  science  which 
should  paint  objects  in  their  truest  colours,  in  terms  most  approaching  to  nature.  It  will, 
therefore,  be  necessary  to  have  recourse  to  the  Greek  and  Latin  languages,  and  perhaps 
to  give  the  preference  to  the  latter,  which  is  generally  understood  by  those  who  prac- 
tise the  art  of  healing.  The  application  of  this  principle  to  the  dirk-rent  kinds  of  fever, 
will^rove  its  utility,  and  will,  doubtless,  be  an  inducement  to  extend  it  to  all  the  classes 
of  morbid  derangements. 

In  febre  infhimmatoria  sen  synocho  simplici  (angeiotenicu)  Opp-ressio  virium. 

In  febre  biliosa  sen  ardente  (meningo-gastrica.)  Fracturu  virium. 

In  febre  pituitosa,  seu  morbo  mucoso  (aclenomeningea)  Languor  virium. 

In  febre  putrida  (adynamica)  Prosiratio  viriitm. 

In  trebribus  malignis  seu  atactis  Jltaxia  virium. 

In  febre  pestilentiali  (adeno-ncrvosa)  Sideratio  virium. 

The  first  term  which  is  easily  turned  into  French,  expresses,  with  much  precision,  that 
condition  in  which  the  living  system,  far  from  being  deficient  in  strength,  is  encumbered 
by  its  excess,  and  is  oppressed  by  its  own  powers.  It  might,  with  slight  modifications, 
be  applied  to  all  the  kinds  of  plegmasias  and  active  hemorrhages. 

The  second  denomination,  not  so  easily  translated,  expresses  the  sense  of  general 
confusion  and  bruise,  of  patients  labouring  under  bilious  fever  (meuingo-gastricu)  com- 
plain all  over  their  limbs. 

This  sensation  is  b'kewise,  it  is  true,  experienced  in  pituitary  fever;  but  this  is  more 
particularly  chcaracterized  by  languor  and  loss  of  strength.  The  same  is  to  be  observed 
in  many  patients  of  a  phlegmatic  temperament. 

The  prostration,  which  is  so  remarkable  a  character  of  putrid  fever,  and  in  conse- 
quence of  which  they  are  called  adynamic,  is  easily  recognized  by  tiie  total  cessation, 
or  by  an  impaired  condition  of  all  the  functions  performed  by  in u scalar  organs,  as  volun- 
tary motion,  respiration,  circulation,  digestion,  the  excretion  of  urine,  &c. 

The  disordered  condition  of  the  vital  powers  characterizes  the  ataxiae;  there  is  con- 
siderable irregularity  in  these  fevers,  with  a  very  anomalous  course  of  symptoms.  In 
this  point  of  view,  one  might  compare  it  to  several  kinds  of  nervous  disorders. 

Lastly,  the  word  sideration  appears  to  me  to  express,  very  forcibly,  that  sudden  and 
deep  stupor  which  overwhelms  patients  seized  with  the  plague  of  the  East. — Author's 
Note. 


323 

CLX  VII.  Of  the  fiower  of  the  muscles;  of  the  mode  of  estimating  thatjiower. 
The  actual  power  of  the  muscles  is  immensely  great,  seems  to  grow  in 
proportion  to  the  resistance  which  it  meets  with,  and  can  never  be  esti- 
mated with  precision.  Borelli  was  guilty  of  a  serious  mistake,  in  esti- 
mating the  force  of  a  muscle  by  its  weight,  compared  to  that  of  another 
muscle,  for  muscles  may  contain  cellular  tissue,  fat,  tendinous  parts,  and 
aponeuroses,  without  being  the  more  powerful.  Their  strength  is  al- 
ways proportioned  to  the  number  of  their  fleshy  fibres;  hence,  Nature  has 
multiplied  those  fibres  in  the  muscles  which  are  intended  for  powerful 
action.  And  in  order  that  this  great  number  of  muscular  fibres  might 
not  add  too  much  to  the  bulk  of  the  limbs,  they  are  made  shorter,  by 
bringing  near  to  each  other  their  insertions,  which  occupy  extensive  sur- 
faces, whether  aponeurotic  or  osseous.  We  may,  in  general,  judge  of  the 
power  of  a  muscle,  by  the  extent  of  the  surfaces  to  which  its  fleshy  fibres 
are  attached  ;  thus,  the  gamelli  and  the  soleus  have  short  compressed 
fibres,  and  lie  obliquely  between  two  large  aponeuroses. 

If  the  force  with  which  a  muscle  contracts,  is  proportioned  to  the 
number  of  its  fibres,  the  degree  of  decurtation  of  which  it  is  capable,  and 
consequently,  the  range  of  motions  which  it  can  communicate  to  the 
limbs,  are  proportioned  to  the  length  of  the  same  fibres*.  Thus,  the  sar- 
torius,  whose  fibres  are  longer  than  any  in  the  human  body,  is  also  capa- 
ble of  most  contraction,  and  performs  the  most  considerable  motions  of 
the  leg.  It  is  impossible  to  fix  any  precise  limits  to  the  decurtation  of 
every  particular  muscular  fibre  ;  for,  if  the  greater  part  of  the  long  mus- 
cles of  limbs  lose  little  more  than  a  third  of  their  length,  in  contracting, 
the  circular  fibres  of  the  stomach,  which,  in  its  greatest  dilatation,  form 
circles  nearly  a  foot  in  diameter,  may  contract,  to  such  a  degree,  when 
this  organ  has  been  long  empty,  as  to  form  rings  of  scarcely  an  inch  in 
circumference.  In  cases  of  extreme  elongation  or  constriction,  does  the 
change  that  take  place,  affect  the  molecules  that  form  the  muscular  fibre, 
or  the  substances  which  connect  them  together,  or  does  it  affect,  at  once, 
both  the  fibre  and  the  parts  by  which  these  fibres  are  united  together? 

However  great  the  power  of  the  muscles  may  be,  a  great  part  of  this 
power  is  lost,  from  the  unfavourable  disposition  of  ourorgans  of  motion; 
the  muscular  powers,  almost  always  parallel  to  the  bones  which  they  are 
to  move,  act  with  the  more  disadvantage  on  these  levers,  as  the  main 
line  of  their  direction  is  further  from  the  perpendicular,  and  is  nearly 
parallel  to  them. 

The  greater  part  of  the  muscles  are,  besides,  inserted  in  the  bones, 
very  near  the  articulations  or  the  centre  of  motion,  and  move  them  as 
levers  of  the  third  kind,  that  is,  are  always  placed  between  the  fulcrum 
and  the  resistance;  by  multiplying  thus,  in  the  animal  machine,  the  levers 
of  the  third  kind,  Nature  has  lost  in  power,  but  has  gained  in  strength, 
for,  in  this  kind  of  lever,  the  power  moves  through  a  very  small  space,  but 
makes  the  resistance  most  through  a  very  considerable  one.  Besides,  the 
fleshy  fibres,  in  shortening  themselves,  do  not  act  directly  on  the  tendon 
in  which  the  muscle  terminates,  these  fibres  generally  join,  in  an  ob- 


*  Besides  these  data,  \ve  should  take  into  consideration  the  energy  of  the  nervous 
impulse,  under  which  voluntary  muscles  contract.  We  perceive  nearly  as  great  differ- 
ences, in  the  activity,  the  intensity,  the  frequency,  and  the  continuance  of  muscular 
contraction,  result  from  the  state  of  the  nervous  system,  even  in  health,  as  may  be  im- 
puted to  the  form  and  size  of  the  muscles  themselves,  unless  the  difference  of  their  con- 
stitution or  size,  be  very  considerable. —  Copland. 


324 

lique  direction,  the  aponeurotic  expansion  formed  by  the  tendinous  cord, 
as  it  penetrates  into  the  muscular  mass;  now  their  action  being  exerted 
in  a  direction  more  or  less  oblique,  is  decomposed  and  none  is  advanta- 
geously employed,  but  that  which  takes  place  in  the  direction  of  the  ten- 
don. The  muscles  frequently  pass  over  several  articulations,  in  their 
way  to  the  bone  which  they  are  to  move  ;  a  part  of  their  power  is  lost,  in 
the  different  degrees  of  motion  on  each  other,  of  the  parts  on  which 
the  bone  rests  into  which  the  muscles  are  inserted.  All  these  organic 
imperfections  are  attended  with  an  enormous  misapplication  of  power 
and  with  a  waste  of  the  greater  part  of  it.  It  has  been  reckoned,  that 
the  deltoid  muscle  employs  a  power  equal  to  2568  pounds  to  overcome  a 
insistence  of  50.  We  are  not  to  imagine,  however,  that  there  is  a  Ijss 
of  2518  pounds  ;  for  the  deltoid  muscle  acting  both  on  the  shoulder  and 
on  the  arm,  about  one  half  of  its  power  is  employed  on  each  of  these 
parts  ;  hence  it  is  said,  that  in  estimating  the  whole  power  of  a  muscle, 
one  should  double  the  effect  produced  by  its  contraction,  its  action  being 
applied,  at  the  same  time,  both  on  the  weight  which  it  raises,  or  on  the 
resistance  which  it  overcomes,  and  on  the  fixed  point  to  which  its  other 
extremity  is  inserted. 

If  the  muscles  were  quite  parallel  to  the  bones,  they  would  be  incapable 
of  moving  them,  in  any  direction.  On  this  account  Nature  has,  as  much 
as  possible  corrected  the  parallelism,  by  removing,  as  we  shall  see,  in 
speaking  of  the  osseous  system,  the  tendons  from  the  middle  line  of  di- 
rection of  the  bones,  and  by  augmenting  the  angles  at  which  they  are  in- 
serted into  them,  either  by  placing,  along  the  course,  bones  which  alter 
their  direction,  as  the  patella  and  the  sesamoid  bones;  by  increasing  the 
size  of  the  articular  extremities  of  the  bones,  or  by  pullies,  over  which 
the  tendons  or  the  muscles  themselves  are  reflected,  more  or  less  com- 
pletely, as  is  the  case  with  the  circumflexus  palati  and  the  obturator  in- 
ternus. 

Nature  has  not,  therefore,  neglected  mechanical  advantages  as  much 
as  one  might  be  led  to  imagine,  on  a  slight  examination  of  the  organs  of 
motion.  And  if  it  be  considered,  that  in  the  different  conditions  of  life, 
we  do  not  require  strength  so  much  as  rapidity  of  motion,  that  the  power 
might  be  gained  by  increasing  the  number  of  fibres,  while  it  was  impos- 
sible to  obtain  velocity,  by  any  other  means  than  by  employing  a  parti- 
cular kind  of  lever,  and  that,  in  short,  to  give  our  limbs  the  most  advan- 
tageous form,  it  was  necessary  that  the  muscles  should  be  applied  to  the 
bones,  it  will  be  confessed,  that  in  the  arrangement  of  these  organs,  Na- 
ture, in  frequently  sacrificing  power  to  quickness  of  motion,  has  conci- 
liated, as  much  as  possible,  these  two  almost  irreconcileable  elements. 

Though  the  lever  of  the  third  kind  is  that  most  frequently  employed  in 
the  animal  economy,  the  two  other  kinds  of  lever  are  not  altogether  ex- 
cluded from  it ;  there  are  even  limbs  which  represent  different  levers,  ac- 
cording to  the  muscles  which  set  them  in  motion  ;  thus,  if  we  take  the 
foot  as  an  instance,  it  will  present  us  with  levers  of  every  kind.  The 
foot,  when  raised  from  the  ground  and  held  up  and  raised  towards  the 
leg,  form,s  a  lever  of  the  first  kind;  the  fulcrum  is  in  the  articulation  and 
separates  the  power,  which  is  at  the  heel,  from  the  resistance  which  is 
at  the  tip  of  the  foot  that  points  downwards ;  if  this  end  of  the  foot  rest 
on  the  ground,  and  if  we  stand  on  tip-toe,  they  are  changed  into  levers  of 
the  second  kind  ;  the  power  continues  at  the  heel,  but  the  fulcrum  is  re- 
moved to  the  other  extremity  of  the  lever,  and  the  resistance  to  the  mid- 
dle; and  this  resistance  is  very  considerable,  since  the  whole  weight  of 


325 

the  body  rests  on  the  articulation  of  the  foot  with  the  leg.  In  standing 
on  tip-toe,  the  muscles  of  the  calf  of  the  leg  become  prodigiously  fatigued, 
though  their  action  is  assisted  by  the  most  favourable  lever*,  adapted  to 
the  greatest  resistance  which  Nature  can  oppose  to  herself.  Lastly,  the 
foot  moves  as  a  lever  of  the  third  kind,  when  we  bend  it  on  the  leg. 

CXLVIII.  What  is  called  the  fixed  point,  in  the  action  of  muscular 
organs,  does  not  always  deserve  that  name.  Thus,  though  it  may  bo  said, 
very  correctly,  that  the  greatest  part  of  the  muscles  of  the  thigh  have 
their  fixed  points  in  the  bones  of  the  pelvis,  to  which  their  upper  extre- 
mity is  attached,  and  though  they  move  the  femur  on  th.1  ilia  which  are 
less  moveable ;  when  the  thigh  is  fixed  by  the  action  of  other  muscles, 
these  move  the  pelvis  on  the  thigh,  and  that  which  was  the  fix?d  point, 
becomes  moveable.  The  same  applies  to  the  other  muscles  of  the  body, 
so  that  the  fixed  point  is  merely  that  which,  generally,  is  a  fulcrum  to 
the  muscular  action.  This  necessary  fixed  state  of  one  of  the  bones,  to 
which  is  attached  one  of  the  extremities  of  a  muscle  which  we  wish  to 
contract,  renders  it  necessary,  in  performing  the  slightest  motion,  thai 
several  muscles  should  be  called  into  action,  which  implies  a  very  com- 
plicated mechanism.  Nothing  is  easier  to  prove.  Suppose  a  man  stretched 
on  the  ground  or  lying  on  his  back;  if  he  wish  to  raise  his  head,  it  will 
be  necessary  that  this  chest  become  the  fixed  point  of  action  of  thesterno 
cleido  mastoidei,  whose  office  it  is  to  perform  this  motion.  Now,  in  order 
that  the  pieces  forming  this  osseous  structure  may  remain  motionless,  it 
will  be  required,  that  the  chest  should  be  fixed  by  the  action  of  the  abdo- 
minal muscles  which,  on  the  other  hand,  have  their  fixed  point  in  the 
pelvis  that  is  itself  fixed  in  its  place,  by  the  contraction  of  the  glutaei 
muscles.  It  was  on  this  principle  that  Winslovv  first  suggested,  that  in 
reducing  a  hernia,  the  patient  should  be  laid  in  an  horizontal  posture^, 
•with  injunctions  not  to  raise  his  head,  that  the  abdominal  muscles  being 
relaxed,  their  different  openings  might  yield  more  easily  to  the  reduction 
of  the  parts. 

In  case  the  two  opposite  points  to  which  the  extremities  of  a  muscle 
are  attached,  are  equally  moveable,  they  approach  towards  each  other, 
during  the  contraction  of  the  muscle,  by  making  them  move  through 
equal  spaces.  These  spaces  would  not  be  equal,  if  the  mobility  were 
different.  Each  muscle  has  its  antagonist,  that  is,  another  muscle  whose 
action  is  directly  opposed  to  it.  Thus,  the  flexors  balance  the  action  of 
the  extensors,  the  adductors  perform  motions  different  from  those  of  the 
abductors.  When  two  antagonizing  muscles  of  equal  power  act,  at  the 
same  time,  on  a  part  equally  moveable,  in  every  direction  on  the  oppo- 
site powers,  neutralize  each  other,  and  the  part  remains  motionless.  If 
there  is  a  difference  in  the  degree  of  contraction,  the  part  is  directed  to- 
wards the  muscle  whose  contraction  is  the  most  powerful  :  if  the  opposi- 
tion is  not  direct,  the  part  follows  a  middle  direction,  between  the  two 
powers  which  move  it.  Thus,  the  rectus  externus  muscle  of  the  eye  is 
not  antagonized  by  the  rectus  inferior ;  hence  when  these  two  muscles 
come  to  contract,  at  the  same  time,  the  eye  is  not  carried  downward  or 
outward,  but  at  once  downward  and  outward  ;  it  is  then  said  to  mote  in 


*  Of  levers  with  arms  of  unequal  length,  that  of  the  second  kind  is  the  most  favoura^ 
ble,  since  the  arm  of  the  power  is  uniformly  longer  than  that  of  the  resistance.  Cop- 
land. 


the  diagonal  of  a  parallelogram  of  which  the  sides  are  represented  by  the 
muscles  in  action. 

CLXIX.  Of  the  nature  of  muscular  flesh.  I  shall  not  speak,  at  present, 
of  the  manner  in  which  the  muscles  receive  nourishment,  by  retaining 
within  the  meshes  of  their  tissue,  the  fibrina  which  the  blood  conveys  to 
them  in  such  quantity,  that  several  among  the  ancients  and  moderns  have 
called  the  blood,  "  liquid  flesh ;"  an  expression  at  once  forcible  and  cor- 
rect, since  all  the  organs  are  repaired  and  grow,  by  the  solidification  of  its 
different  parts.  Haller  first  observed  that  most  of  the  muscular  arteries 
were  very  tortuous  in  their  course  to  the  muscles.  This  disposition, 
which  cannot  fail  to  slacken,  very  considerably,  the  course  of  the  blood, 
favours  the^  formation  and  the  secretion  of  the  fibrous  element  which  the 
muscles  appropriate  to  their  own  substance,  and  to  which  it  bears  so 
strong  an  affinity.  Motion  influences,  in  a  very  remarkable  manner,  this 
nutritive  secretion.  The  muscles  that  are  most  in  action,  uniformly 
acquire  the  greatest  size  and  strength ;  if  left  in  a  state  of  complete  inac- 
tion, they  become  exceedingly  reduced  in  size,  from  the  suspended  secre- 
tion of  the  fibrinous  principle.  Muscular  motion  promotes,  very  remark- 
ably, the  circulation  and  the  distribution  of  all  the  fluids.  The  flow  of 
venous  blood,  after  bleeding,  is  never  copious,  unless  the  muscles  of  the 
fore  arm  are  made  to  contract,  by  making  the  patient  hold  the  lancet  case, 
and  desiring  him  to  move  it  round  his  hand.  , 

The  chemical  nature  of  the  muscular  fibre  is  nearly  the  same  as  that  of 
the  fibrina  obtained  from  the  blood*.  Like  the  latter,  it  contains  a  great 
quantity  of  azote,  and  is,  consequently,  very  much  animalized  and  ex- 
ceedingly putrescent.  It  is  from  muscular  flesh,  that  M.  Berthollet  ob- 
tained, in  considerable  quantity,  the  peculiar  animal  acid,  called  by  that 
chemist,  the  zoonic  acid^.  Lastly,  the  element  of  the  blood,  by  means  of 
which  the  muscular  flesh  is  repaired,  fibrina,  is  already  imbued  with  vital 
properties,  even  while  it  yet  flows  in  a  state  of  combination  with  the  other 
parts  of  the  fluid.  This  fibrina,  extracted  from  the  blood  and  subjected 
to  the  galvanic  influence,  is  distinctly  seen  to  quiver  and  contract  under 
that  influence.  At  what  period  does  this  substance  acquire  the  power  of 
contracting-?  It  is,  doubtless,  at  the  moment  when  it  becomes  organized, 
in  passing  from  the  fluid  to  the  solid  state.  What  relation  does  there 
exist,  between  the  organization  of  matter  and  the  vital  properties  with 
which  it  is  endowed?  This  question  cannot  be  answered,  in  the  present 
state  of  our  physiological  knowledge:}:. 

CLXX.  Galvanism.  A  Professor  of  Anatomy  in  the  University  of 
Bologna,  Galvani,  was  one  day  making  experiments  on  electricity.  In 
the  laboratory,  not  far  from  the  machine,  lay  some  skinned  frogs,  of  which 

*  Nothing1  can  prove,  in  a  more  complete  manner,  the  essential  difference  between 
the  fleshy  parts  of  muscles  and  their  tendinous  and  aponeurotic  parts,  than  the  chemical 
analysis  of  these  organs.  The  tendons  and  aponeuroses  may  be  completely  resolved 
into  g-elatine,  by  long  boiling1,  which,  on  the  contrary,  parches  the  muscular  flesh,  by 
exposing1  the  fibrina,  in  consequence  of  the  melting  of  the  fat  of  the  cellular  tissue,  and 
of  the  albuminous  juices  in  which  it  is  enveloped. — See  the  Chapter  at  the  end  of  the 
APPKSBIX,  on  the  Chemical  Constitution  of  the  Animal  Textures  and  Secretions. 

j"  Another  secretion  which  is  obtained  abundantly  from  muscular  tissues,  and  denomi- 
nated osmazome  by  modern  chemists,  may  be  noticed.  It  appears  to  be  a  species  of 
animal  extract,  of  a  brown  colour,  aromatic,  and  very  nutritious.  It  gives  soup  its  savour, 
and  forms  a  great  proportion  of  the  gravy  of  meat.  Although  osmazome  is  an  animal 
product,  it  is  found  on  analysis  in  some  species  of  mushrooms. 

T  See  APPENDIX,  Note  F  F. 


327 

the  limbs  were  convulsed  every  time  a  spark  was  taked.  Galvani,  struck 
with  the  phenomenon,  made  it  a  subject  of  inquiry,  and  found  that  metals? 
applied  to  the  nerves  and  to  the  muscles  of  these  animals,  determined 
quick  and  strong  contractions,  when  they  were  disposed  in  a  certain  man- 
ner. He  gave  the  name  of  Animal  Electricity  to  this  set  of  new  pheno- 
mena, from  the  analogy  he  thought  he  perceived  between  its  effects  and 
those  of  electricity.  The  discovery  was  made  public:  many  scientific 
men,  chiefly  those  of  Italy,  and  Volta  among  others,  were  eager  to  make 
additions  to  the  labour  of  the  inventor.  The  Medical  Society  of  Edin- 
burgh thought  it  right  to  take  this  point  of  physiology  as  the  subject  of 
one  of  its  annual  prizes,  which  was  adjudged  to  the  work  of  Professor 
Creve  of  Mentz,  in  which  the  term  metallic  irritation  (irrllamentum  me- 
lallorum}  is  substituted  for  that  of  animal  electricity.  This  new  expres- 
sion is  essentially  bad,  since  it  implies  that  irritation  by  metals  can  alone 
determine  the  galvanic  phenomena,  when  charcoal,  water,  and  many  other 
substances,  produce  them  as  well.  The  term  of  animal  electricity  has 
been  also  laid  aside,  notwithstanding  the  great  analogy  between  the  effects 
of  electricity  and  those  of  galvanism,  and  this  last  name  has  been  pre- 
ferred, which,  applying  equally  to  the  whole  of  the  phenomena,  immor- 
talizes the  name  of  the  first  observer*. 

To  produce  the  galvanic  phenomena,  it  is  necessary  to  establish  a 
communication  between  two  points  of  a  series  of  nervous  and  muscular 
organs.  In  this  way  there  is  formed  a  circle,  of  which  one  arc  is  com- 
posed of  the  animal  parts  that  are  subjected  to  the  experiment;  while  the 
other  arc  is  represented  by  the  instruments  of  excitation,  which  consist 
commonly  of  several  pieces,  some  of  them  placed  under  the  animal  parts, 
and  called  supports,  and  the  others,  by  which  the  communication  with 
these  is  established,  called  communicators. 

To  form  a  complete  galvanic  circle,  take  the  thigh  of  a  frog  stripped  of 
its  skin,  detach  the  crural  nerve  down  the  knee,  and  apply  it  on  a  plate 
of  zinc;  let  the  muscles  of  the  leg  lie  on  a  plate  of  silver,  then  complete 
the  arc  of  excitation  and  the  galvanic  circle,  by  establishing  a  communi- 
cation between  the  two  supports  with  an  iron  wire,  or  copper,  tin,  or 
lead:  at  the  moment  of  touching  the  two  supports  with  the  conductor, 
a  part  of  the  animal  arc  formed  by  the  muscles  of  the  leg,  will  be  con- 
vulsed. Although  this  arrangement  of  the  animal  parts,  and  of  the  gal- 
vanic instruments,  is  the  one  most  favourable  to  the  production  of  these 
phenomena,  there  is  room  for  varying  a  good  deal  the  composition  of  the 
animal  arc  and  the  arc  of  excitation.  Thus,  you  obtain  contractions,  by 
placing  the  two  supports  under  the  nerve,  and  leaving  the  muscles  with- 

*  SUI.ZF.H,  in  the  Memoirs  of  the  Academy  of  Berlin,  and  in  his  "  General  Theory  of 
Pleasure"  a  work  published  in  1757,  and  inserted  in  1769,  in  a  collection  published  by 
Bouillon,  under  the  title  of  the  "  Temple  du  Honheur,"  tome  III.  p.  124,  had  mentioned, 
that  two  plates  of  different  metals  being  placed  one  above  and  another  below  the 
tongue,  and  inclined  towards  each  other  at  their  extremities,  at  the  moment  when  they 
touched  each  other,  he  felt  a  sharp  taste,  which  was  frequently  accompanied  by  a  pecu- 
liar faint  light.  COTUGNO  had  related  in  a  Journal  published  at  Bologna,  in  1786,  that 
a  student  of  medicine,  while  dissecting  a  living- mouse,  was  surprised  to  observe  an  elec- 
tric movement  of  its  limbs  whenever  the  scalpel  touched  one  of  its  nerves.  It  was  not 
until  1789,  that  GALVANI  commenced  his  experiments.  But  he  cannot  be  the  less  con- 
sidered as  the  discoverer  of  this  class  of  phenomena,  even  supposing  that  he  knew  the 
experiments  we  have  noticed,  for  their  authors  drew  no  conclusion  from  them ;  while, 
on  the  contrary,  Galvani  repeated,  varied,  and  multiplied  them,  and  was  the  first  to. 
contend  for  a  species  of  electricity  in  the  animal  economy. 


328 

out  the  galvanic  circle;  which  proves,  that  the  nerves  essentially  consti- 
tute the  animal  arc.  To  conclude,  the  galvanic  circle  may  be  entirely 
animal:  for  this  purpose,  take  a  very  lively  frog,  that  is  to  say,  .me  en- 
joying strong  contractility:  after  insulating  the  lumbar  nerves,  present 
these  nerves  to  the  thigh  of  the  frog ;  at  the  moment  of  contact,  the  limb 
will  be  convulsed.  Professor  Aldini  is  the  first  author  of  this  experiment, 
which  is  really  one  of  the  most  curious,  as  it  leads  more  directly  to  the 
explanation  of  the  influence  of  nerves  on  muscular  organs. 

There  is  no  need  that  the  nerves  be  untouched  to  allow  the  contrac- 
tions, they  are  observed  when  these  organs  are  tied  or  cut,  provided  there 
be  simple  contiguity  between  the  two  ends  made  by  the  section.  This 
shows  that  no  rigorous  conclusions  must  be  drawn  from  what  happens  in 
galvanic  phenomena,  to  what  takes  place  in  muscular  action;  since  it  is 
enough  that  a  nerve  in  man  be  cut  or  compressed  by  a  ligature,  to  take 
from  the  muscles  to  which  if.  is  sent,  the  faculty  of  moving.  I  have, 
however,  observed,  that  disorganizing,  by  strong  contusion,  the  nerve 
which  forms  the  whole  or  merely  a  part  of  the  animal  arc,  interrupts,  or 
at  least  greatly  impedes,  the  galvanic  current. 

The  epidermis  obstructs  galvanic  action;  which  always  is  faint  in  parts 
so  covered.  When  it  is  moist,  thin,  and  delicate,  the  interruption  is  not 
complete;  and  hence  the  possibility  is  inferred  of  making  on  one's  self  the 
following  experiments. 

Lay  upon  the  tongue  a  plate  of  silver,  and  a  plate  of  zinc  beneath;  let 
their  edges  touch,  and  you  will  feel  a  sharp  t?,ste  with  a  slight  quivering. 
Apply  upon  the  eyes  two  pieces  of  different  metals;  make  them  commu- 
nicate, and  you  will  perceive  sparks.  Put  apiece  of  silver  in  your  mouth, 
and  a  piece  of  tin  into  your  anus,  or  copper,  or  any  other  metal;  connect 
them  with  an  iron  wire:  the  long  hollow  muscle,  which,  reaching  from 
the  mouth  to  the  anus,  forms  the  base  of  the  digestive  canal,  feels  a  con- 
siderable shock:  this  has  been  carried  to  the  length  of  exciting  a  gentle 
purging,  accompanied  with  slight  cholic.  Humboldt,  after  detaching  the 
epidermis  from  the  nape  of  the  neck,  and  the  back,  by  two  blisters,  had 
metals  applied  to  the  parts  laid  bare;  and  felt  in  each  sharp  prickings, 
accompanied  with  a  sero-sanguineous  excretion,  at  the  moment  of  com- 
munication. 

You  may  construct  the  arc  of  excitation  with  three  kinds  of  metal,  or 
two,  or  even  one;  with  alloys,  amalgams,  or  other  metallic  and  mineral 
combinations;  with  carbonaceous  substances,*  Sec.  and  it  is  observed,  that 
metals,  which  are  in  general  the  most  powerful  exciters,  provoke  con- 
tractions with  the  greater  success  the  larger  surface  they  present.  The 
metals  have  more  or  less  power  of  excitation:  thus  it  is  found  that  zinc, 
gold,  silver,  and  tin,  hold  the  first  rank;  then  copper,  lead,  nickel,  anti- 
mony, &c.  without  any  apparent  relation  between  their  different  degrees 
of  exciting  power,  and  their  physical  properties,  as  their  weight,  malle- 
ability, Sec. 

CLXXI.  Galvanic  susceptibility  is  like  muscular  irritability;  it  is  ex- 
hausted by  too  long  exertion;  and  returns  when  the  parts  are  left  for  a 
time  to  repose.  Dipping  the  nerves  or  muscles  in  alcohol  or  opiate 
solutions,  weakens  and  even  will  extinguish  this  susceptibility,  in  the 
same  manner,  no  doubt,  as  in  the  living  man,  the  immoderate  use  of  the 

*  1  employed  successfully,  in  the  winter  of  the  year  1800,  pieces  of  ice,  both  as  sup- 
ports and  as  communicators. 


same  substances  benumbs  and  paralyzes  the  muscular  action.  Immer- 
sion in  oxygenated  muriatic  acid  restores  to  the  exhausted  parts  the 
power  of  being  affected  by  the  stimulus.  Humboldt  has  observed,  that 
the  season  of  spring,  as  well  as  the  youth  of  the  frog,  was  favourable  to 
the  production  of  the  phenomena:  and  that  the  fore  feet  of  these  creatures 
with  which  the  male  fixes  himself  on  the  back  of  the  female,  by  pressing 
her  sides,  are  more  excitable  than  the  hind  feet;  whilst  in  the  other  sex, 
it  is  the  hind  feet  that  are  the  most  susceptible.  Halle  ascertained,  by 
experiments  made  at  the  School  of  Medicine  in  Paris,  that  the  muscles 
of  animals  killed  by  repeated  shocks  of  an  electrical  battery,  receive  an 
increase  of  galvanic  susceptibility;  that  this  property  subsists,  without 
alteration,  in  animals  dead  of  asphyxia,  or  killed  by  immersion  in  mer- 
cury, pure  hydroden  gas,  carbonated  hydrogen,  oxygenated  muriatic 
acid,  and  sulphureous  acid  gases,  by  strangulation,  by  privation  of  air  in 
an  exhausted  receiver;  that  it  is  weakened  after  suffocation  by  drowning, 
by  sulphurated  hydrogen,  azote,  and  ammoniacal  gas,  and  absolutely  de~ 
stroyed  by  suffocation  in  the  vapour  of  charcoal.  Spring  is  the  season 
in  which  galvanic  experiments  succeed  best;  an  excess  of  life  seems,  at 
that  time,  to  animate  all  beings:  it  is  accordingly  at  this  epoch,  that  the 
greater  part  of  them  are  employed  in  the  reproduction  of  their  kind. 

CLXXII.  Galvanic  susceptibility  disappears  in  the  muscles  of  warm' 
blooded  animals,  as  the  vital  warmth  goes  off.  Sometimes  even,  when 
their  life  has  ended  in  convulsions,  their  contractility  is  gone,  though 
there  be  still  warmth,  as  if  this  vital  property  were  exhausted  by  the  con- 
vulsions of  death.  In  the  cold-blooded,  susceptibility  is  more  permanent: 
long  after  separation  from  the  body,  and  even  to  the  moment  when  pu- 
trefaction begins,  the  thighs  of  frogs  are  affected  by  galvanic  excitation; 
no  doubt,  because,  in  these  animals,  irritability  is  less  intimately  con- 
nected with  respiration,  because  life  is  less  one,  is  more  divided  among 
different  organs  which  have  less  need  of  action  on  each'  other  to  produce, 
its  phenomena. 

Contractility  is  then,  as  I  have  shown  in  another  work,  too  fleeting  in 
the  human  body*,  to  enable  us  to  derive  from  galvanic  experiments  on 
it  after  death,  any  light  on  the  greater  or  less  weakening  of  this  vital 
property  in  different  diseases.  Those  authors  who  have  maintained  that 
galvanic  susceptibility  is  sooner  extinct  on  the  bodies  of  those  that  die  of 
scorbutic  affections,  than  of  those  that  die  of  inflammatory  diseases,  have 
suggested  a  probable  conjecture,  which  cannot,  however,  be  established' 
on  experiment. 

Dr.  Pfaff,  Professor  in  the  University  of  Kiel,  who,  next  to  Humboldt, 
of  all  the  scientific  men  of  Germany,  has  attended  most  successfully  to 
experiments  on  galvanism,  has  had  the  goodness  to  communicate  to  me 
the  following  facts. 

The  galvanic  chain  produces  sensible  actions,  that  is  to  say,  contrao 
tions,  only  at  the  moment  in  which  it  is  completed,  by  establishing  a 
communication  among  its  parts.  After  it  is  made,  that  is,  during  the 
time  that  the  communication  remains,  all  appears  tranquil;  yet  the  gal- 
vanic action  is  not  suspended.  In  fact,  excitability  appears  singularly- 
increased  or  diminished  in  the  muscles  that  have  been  left  long  in  the 
galvanic  chain,  according  to  the  variations  of  the  reciprocal  situation  of 

the  new"born  or  Ver7  y°un£  info"**  almost  immediately 


330 

the  associated  metals.  If  the  silver  have  been  applied  to  the  nerves, 
and  the  zinc  to  the  muscles,  the  irritability  of  these  is  increased,  in  pro- 
portion to  the  time  they  have  remained  in  the  chain.  By  this  means, 
you  may  revivify,  in  some  sort,  frogs'  thighs,  which  will  after  wards  obey 
an  influence  that  was  no  longer  sufficient  to  excite  them.  By  allotting 
the  metals  differently,  applying  the  zinc  to  the  nerves,  and  the  silver  to 
the  muscles,  the  opposite  effect  takes  place,  the  muscles  which  were  in- 
troduced into  the  chain  with  the  liveliest  irritability,  seem  entirely  para- 
lyzed, if  they  have  remained  long  in  that  situation. 

This  difference  depends,  very  evidently,  on  the  direction  of  the  galvanic 
fluid,  determined  towards  the  nerves  or  towards  the  muscles,  according 
to  the  arrangement  of  the  metals.  It  is  of  importance  to  be  known  for 
the  application  of  galvanism  to  the  treatment  of  disease.  Where  the  ob- 
ject is  to  revive  enfeebled  irritability,  it  is  better  to  employ  the  tranquil 
and  permanent  influence  of  the  closed  galvanic  chain,  by  distributing  the 
silver  and  zinc,  so  that  the  silver  shall  be  nearest  to  the  origin  ot%  the 
nerves,  and  the  zinc  upon  the  muscles  of  which  it  is  wished  to  re-excite 
the  torpid  or  suspended  action,  than  to  employ  that  sudden  influence, 
\vhich  in  an  instant,  excites  and  is  gone.  Professor  Pfafi°  told  me,  he  had 
treated  successfully  a  hemiplegia,  by  placing  silver  within  the  mouth, 
and  a  plate  of  zinc  on  the  paralyzed  arm;  at  the  end  of  twenty-four  hours 
of  uninterrupted  communication,  the  limb  could  already  exert  some  slight 
motions.  To  diminish,  on  the  other  hand,  the  irritable  energy  in  many 
spasmodic  affections,  you  must  invert  the  application  of  the  metals,  place 
the  zinc  as  near  as  possible  to  the  central  extremity  of  the  nerves,  and 
the  silver  on  their  superficial  terminations. 

CLXXIII.  Apparatus  of  Volta,  or  galvanic  pile.  Curious  to  ascertain 
the  relation  apprehended  by  several  natural  philosophers,  between  elec- 
tricity and  galvanism,  Volta  invented  the  following  apparatus,  which  is 
described,  as  well  as  the  effects  it  produces,  in  a  memoir  presented  by 
him  to  the  Royal  Society  of  London.  These'  effects  show  the  most 
striking  analogy  between  these  two  orders  of  phenomena,  as  will  be  seen 
by  a  succinct  view  of  them.  Raise  a  pile,  by  laying  successively,  one 
above  another,  a  plate  of  zinc,  a  piece  of  moistened  paste-board,  a  plate 
of  silver;  then  a  second  plate  of  zinc,  Sec.  till  the  pile  is  several  feet  high; 
for  the  effects  are  stronger  the  higher  it  is:  then  touch  at  once  the  two 
extremities  of  the  pile  with  the  same  iron  wire:  at  the  instant  of  contact, 
a  spark  is  seen  at  the  extremities  of  the  pile,  and  often,  at  the  same  time, 
luminous  points,  at  different  heights,  in  places  where  the  zinc  and  silver 
touch.  Tried  by  the  electrometer  of  Coulomb,  the  extremity  of  the  pile, 
which  answers  to  the  zinc,  appears  positively  electrified;  that  which  is 
formed  by  the  silver,  gives,  on  the  contrary,  indications  of  negative  elec- 
tricity. 

If,  after  wetting  both  hands,  by  clipping  them  in  water,  or  still  better 
in  a  saline  solution,  you  touch  the  two  extremities  of  the  pile,  you  feel  in 
the  joints  of  your  fingers  and  elbow,  a  shock  followed  by  an  unpleasant 
pricking. 

This  effect  may  be  felt  by  several  persons  holding  hands,  as  in  the  Ley- 
den  experiment;  it  is  the  more  sensible,  the  composition  of  the  chain  be- 
ing in  other  respects  the  same,  as  the  chain  consists  of  fewer  people,  and 
a£  they  are  better  insulated. 

Notwithstanding  this  great  resemblance  of  the  effects  of  galvanism  to 
those  of  electricity,  it  differs  from  it  essentially  in  this,  that  the  voltaic 


331 

pile  is  constantly  electrifying  itself  spontaneously,  that  its  effects  seem  in- 
creased, the  more  they  are  excited,  and  are  speedily  renewed  in  greater 
strength,  whilst  the  Leyden  phial,  once  discharged,  requires  to  be  elec- 
trified anew.  This  loses,  moreover,  by  damp,  its  electrical  properties, 
whilst  those  of  the  pile  remain  the  same,  though  water  is  running  on  all 
side,  and  are  quenched  only  by  an  entire  immersion  in  that  fluid. 

If  you  introduce  into  a  tube  filled  with  water,  and  hermetically  closed 
•with  two  corks,  the  extremities  of  two  wires  of  the  same  metal,  which, 
at  the  other  extremity,  are  in  contact,  one  in  the  summit  and  one  with 
the  base  of  the  galvanic  pile,  these  two  ends,  when  brought  within  the 
distance  of  a  few  lines,  undergo  manifest  changes,  at  the  moment  of  touch- 
ing the  extremities  of  the  pile.  The  wire  in  contact  with  the  extremity 
which  answers  to  the  zinc,  becomes  covered  with  bubbles  of  hydrogen 
gas;  that  which  touches  the  extremity  formed  by  the  silver,  becomes 
oxydized.  If  the  ends  of  the  wire  dipping  into  the  water,  are  brought  into 
contact,  all  effect  ceases:  there  is  no  disengaging  of  bubbles  on  one  side, 
no  oxydizement  on  the  other.  The  plates  of  zinc  and  silver  become  alike 
oxydized  in  the  pile,  but  only  on  the  surfaces  which  touch  the  moisten- 
ed pasteboard,  and  very  little,  or  not  at  all,  on  the  opposite  surfaces,  &c. 

Facts  so  singular  could  not  but  awaken  the  attention  of  all  natural 
philosophers.  Accordingly,  there  was  a  great  eagerness,  every  where, 
to  repeat  and  verify  these  first  experiments,  to  vary  and  to  extend  them, 
and  to  rectify  the  errors  into  which  their  authors  might  have  fallen. 
Lastly,  it  has  been  attempted  to  explain  the  manner  in  which  the  apparatus 
acts  in  the  production  of  hydrogen  gas  and  in  oxydizement. 

M.  Fourcroy  ascribes  this  phenomenon  to  the  decomposition  of  water 
by  the  galvanic  fluid,  which  abandons  the  oxygen  to  the  wire  that  touches 
the  positive  extremity  of  the  apparatus,  then  conducts  the  other  gas,  in 
an  invisible  manner,  to  the  extremity  of  the  other  wire,  where  it  allows 
it  to  escape  ;  and  this  opinion,  supported  by  many  experiments,  detailed 
in  a  Memoir  presented  to  the  National  Institute,  is  the  most  probable  of 
^11  that  have  hitherto  been  suggested*. 

The  galvanic  pile  has  been  employed,  with  effect,  to  produce  witli 
more  energy,  muscular  contraction.  If  you  place  in  the  mouth  of  an  ani- 
mal, fresh  killed,  a  conductor  attached  to  one  of  the  poles  or  extremities 
of  the  pile,  and  insert  into  the  rectum,  the  conductor  connected  with  the 
other  extremity,  you  observe  contractions  so  strong,  that  the  whole  body 
of  the  animal  quivers  and  is  agitated,  the  eyes  roll  in  their  socket*,  the 
jaws  strike  against  each  other,  and  the  tongue  is  thrust  out.  The  same 
effects  take  place  after  decapitation  of  the  animal.  These  experiments 
have  been  repeated  on  the  bodies  of  persons  executed  by  the  guillotine  : 
by  applying  to  the  neck,  the  head  that  had  been  separated  from  it,  and 
applying  to  both  conductors  connected  with  the  pile,  effects  have  been 
produced,  which  seemed  at  first  miraculous.  There  are  fewrauscies  that  re- 
tain, longer  than  the  diphragm,  their  sensibility  to  the  galvanic  action; 
in  the  heart,  and  in  the  intestines,  it  is  the  same.  I  know  not  why  the 
internal  muscles  have  been  held  by  many  authors  to  be  insensible  to  this 
kind  of  excitation.  I  have  seen  them  constantly  obey  it,  and  many  ex- 


*  It  is  unnecessary  to  refer  to  the  brilliant  discoveries  which  have  been  made*  in  chemi- 
cal science  by  means  of  galvanism. 


332 

periments  made  publicly  in  my  lectures,  have  ahvay  afforded  me  this  re- 
sult*. 

CLXXIV.  In  the  first  edition  of  this  work,  the  article  galvanism  prid- 
ed here*  Since  its  publication,  there  has  been  an  accession  of  new  facts 
to  those  already  known.  Volta  came  to'Paris:  he  gave  an  exposition  of 
his  doctrine,  in  several  Memoirs  read  before  the  National  Institute  of 
France,  and  he  repeated  before  acommitee,  the  principal  experiments  on 
which  it  is  founded*  They  have  appeared  so  conclusive,  that  the  theory 
of  this  illustrious  philosopher  has  been  unanimously  adopted,  and  at  this 
day,  all  men  of  science  admit  the  entire  identity  of  the  phenomenon  of 
galvanism,  and  those  of  electricity.  Certain  bodies,  therefore,  in  nature, 
and  especially  metals  possess  the  property  of  electrifying  themselves, 
that  is  to  say,  of  producing  the  greater  part  of  the  phenomena  which 
denote  the  accumulation  of  electricity  in  a  body,  such  as  shocks,  sparks, 
irritations,  Sec.  merely  by  contactf. 

It  maybe  thought  that  galvanism*  being  only  a  new  form  of  electrical 
action,  ought  to  be  confined  to  books  of  natural  philosophy;  and  in  fact, 
in  the  present  state  of  things,  it  belongs  rather  to  the  physico-chemical 
sciences,  than  to  those  of  the  animal  economy.  However  the  galvano- 
electric  irritation  produces  on  our  organs,  effect  more  decided  than  the 
ordinary  effect  of  electricity.  It  seems  to  have  more  intimate  relations 
•with  them:  accordingly,  it  has  been  endeavoured  to  bring  it  into  use  in 
the  treatment  of  disease,  The  experiments  made  by  M.  M.  Halle  and 
Thillaye,  prove  that  the  effects  of  the  pile  penetrate,  and  effect  the  nerv- 
ous and  muscular  organs,  more  deeply  than  the  common  electrical  appa- 
ratus; that  they  provoke  lively  contractions  strong  sensations  of  pricking 
and  burning,  in  parts  which  disease  renders  insensible  to  electrical  sparks, 
or  even  shocks.  A  man  whose  muscles  of  the  left  side  of  his  face  were 
all  paralyzed,  found  no  effect  from  the  electric  shock.  He  was  exposed 
to  the  action  of  a  pile  of  50  plates,  by  communications,  through  chains 
and  metalic  exciters,  of  the  two  extremities  of  the  pile,  with  different 
points  of  the  cheek  affected,  At  the  moment  of  contact,  all  the  muscles 
of  the  face  became  convulsed  with  heat*  pain,  Sec.  These  endeavours 
repeated,  during  more  than  six  months,  have,  by  degrees,  brought  back 
the  parts  to  their  natural  state. 

Dr.  Alibert  has  applied  galvanism  with  still  more  decided  success,  to 
a  priest  attacked  with  hemiplegia.  This  patient,  who  lay  in  the  wards  of 
the  Hospital  of  St.  Lewis,  has  recovered  the  use  of  the  palsied  side,  suf- 
ficiently to  walk,  almost  without  assistance,  and  to  use  his  right  arm  ,as 
he  wants  it.  The  treatment  has  gone  on  for  several  months:  the  pile 
employed  consisted  of  fifty  plates  of  zinc  and  copper,  I  am  trying  the 
same  apparatus  upon  a  Swedish  officer,  for  incomplete  deafness,  which 
has  hitherto  resisted  all  known  applications,  administered  in  different 
parts  of  Germany,  Strong  electrical  shocks,  recommended  by  Hufeland, 
had  dispelled  in  great  measure,  the  hardness  of  hearing;  but  this  amend- 
ment was  only  temporary:  it  ceased  with  the  application  of  the  remedy. 
The  first  trial  of  galvanism  was  attended  with  the  same  effect.  The  ex- 


*  See  the  Note  in  the  APPENDIX  ort  the  subject  of  galvanism,  for  some  observations 
as  to  the  effects  of  this  agent  on  some  of  the  animal  textures. 

j  See  APPENDIX,  Note  G  G  for  an  account  of  some  receftt  views  respecting  the  rela- 
tions and  agencies  of  galvanism,  &c. 


333 

tremity  of  a  conductor  being  placed  in  the  exterior  auditory  duct  of  the 
right  side  (moistened  with  a  solution  of  muriate  of  ammonia,  as  well  as 
the  pieces  of  cloth  which  made  part  of  the  pile)  the  left  hand,  dipped  in 
the  same  liquid,  touched  a  conductor  placed  at  the  copper  pole:  imme- 
diately an  irritation,  followed  by  painful  prickings,  was  felt  in  the  ear, 
the  outer  part  of  which  became  very  red.  The  brain  partook  in  the  ex- 
citement, the  eyes  flashed,  and  the  effect  was  such,  that  after  remaining 
a  few  minutes  in  the  closed  galvanic  circle,  the  patient  was  taken  with  a 
sort  of  inebriation.  I  propose  to  direct,  as  has  been  done  at  Berlin,  a 
more  immediate  irritation  of  the  right  ear,  which  is  the  deafest,  by  intro- 
ducing behind  the  velum  palati,  on  the  guttural  orifice  of  the  eustachian 
tube,  the  button  which  is  at  the  end  of  the  conductor  of  the  zinc  pole;  or 
else  to  make  this  extremity  correspond  with  a  denuded  surface,  by  a  blis- 
ter behind  the  diseased  ear. 

To  use  galvanism  in  paralysis  of  the  bladder,  it  would  be  necessary  to 
place  the  conductor  of  the  zinc  pole  in  the  rectum,  that  of  the  other  pole 
answering  to  a  blister  applied  above  the  pubis,  or  else  to  the  upper  part 
of  the  thigh.  In  women,  the  vagina  would  be  preferable  to  the  rectum  ; 
the  soft  parts  which  perform  the  part  of  moist  conductors  fulfilling  that 
office  the  better,  the  thinner  they  are.  Galvanism  is  therefore  an  ener- 
getic stimulant  of  the  vital  powers;  it  may  be  employed,  with  great  ad- 
vantage, in  all  palsy,  both  of  sensation  and  of  motion.  It  acts  as  a  sti- 
mulant, reddening  the  skin  where  it  is  applied,  by  determining  thither 
the  flow  of  blood,  with  heat.  Monro  could  make  his  nose  bleed  at  plea- 
sure, by  applying  it  to  the  pituitary  membrane.  I  have  made  various 
experiments,  having  in  view  to  establish  the  efficacy  of  galvanism,  in 
white  swelling  of  the  joints,  and  in  ulcers  which  require  excitement;  such 
as  those  which  are  attended  with  a  scorbutic  affection,  Sec.  in  all  these 
cases,  it  acts  as  a  resolvent,  and  as  a  ionic.  I  shall  communicate,  in  my 
Surgical  Nosography,  the  results  of  these  attempts.  Cases  of  Asphyxia 
are  those  in  which  the  greatest  good  may  be  hoped  from  galvanism, 
provided  the  application  be  made  before  all  the  vital  heat  be  extinct*. 

Those  who  wish  fuller  details  on  galvanism,  and  on  its  possible  appli- 
cation to  the  treatment  of  disease,  will  do  well  to  consult  the  Complete 
History  of  Galvanism,  by  Professor  Sue,  the  eulogium  of  Galvani,  by  Dr. 
Alibert,  in  the  beginning  of  the  fourth  volume  of  the  Memoirs  of  the 
Medical  Society  of  Emulation,  and  the  work  of  Dr.  Aldini,  nephew  to 
the  celebrated  author  of  the  discoveryf. 

CLXXV.  General  view  of  the  osseous  system.  Man,  as  well  as  the  other 
red-blooded  animals,  (the  mammiferae,  birds,  reptiles,  and  fishes,)  has  an 
internal  skeleton,  formed  of  a  great  number  of  bones  articulated  together, 
and  set  in  motion  by  the  muscles  with  which  they  are  covered.  The 
white-blooded  animals  have  no  internal  skeleton,  and  are  enveloped,  in 
hard,  scaly,  or  stony  parts,  forming  what  is  called  their  outer  skeleton. 


*  Dr.  PHILIP  is  of  opinion  that,  in  those  diseases  in  which  the  original  cause  of  de- 
rangement is  in  the  nervous  ramifications,  or  spinal  cord,  only,  where  the  sensorial 
functions  are  entire,  and  the  vessels  healthy,  and  the  po\vcr  of  secretion  is  alone  in 
fault,  galvanism  will  oiten  prove  a  valuable  means  of  relief.  He  has  frequently  em- 
ployed  it  in  hab'tual  asthma,  «  and  almost  uniformly  with  relief."  He  aho  recommends 
this  active  agent  in  a  torpid  state  of  the  biliary  functions,  and  In  indigestion.  See  a 
Treatise  on  Indigestion,  by  Dr.  Philip,  3d  edition,—  Copland. 

t  Se«  APPENDIX,  Note  G  G. 


334 

Some  animals  are  entirely  destitute  of  hard  parts:  this  is  the  case  with  the 
zoophytes,  some  worms  and  insects.  The  internal  structure  of  bones  is 
composed  of  nearly  the  same  materials  in  all  animals:  viz.  gelatine  and 
salts  containing-  a  calcareous  basis.  The  external  skeleton  of  white-blood- 
ed animals  bears  a  much  greater  resemblance  to  the  epidermis  than  to 
the  osseous  system  of  the  red-blooded  animals.  Like  the  epidermis,  it 
undergoes  changes  of  decomposition  and  renovation.  Thus,  the  lobster 
parts  with  its  shell,  every  year,  when  the  body  of  this  crustaceous  animal 
increases  in  size,  and  it  is  replaced  by  a  new  envelope,  which  is,  at  first, 
very  soft,  and  which  gradually  acquires  the  same  consistence  as  the 
former.  Lastly,  the  skeleton  of  birds  differs  from  that  of  all  other  ani- 
mals, in  having  its  principal  bones  pierced  by  openings  communic'iting 
with  i he  lungs,  and  always  filled  with  an  air  rarified  by  the  vital  heat, 
winch  greatly  assists  in  giving  to  them  that  specific  lightness  so  essential 
to  their  peculiar  mode  of  existence. 

The  osseous  system  serves  as  a  foundation  to  the  animal  machine, 
yields  a  firm  support  to  all  its  parts,  determines  the  size  of  the  body,  its 
proportion,  its  form  and  attitude.  Without  the  bones,  the  body  would 
have  no  permanent  form,  and  could  not  easily  move  from  one  place  to 
another.  When,  from  the  loss  of  the  calcareous  earth  to  which  they  owe 
their  hardness,  these  organs  become  soft,  the  limbs  deformed,  standing, 
and  the  different  motions  of  progression,  become  after  a  time  impossible. 
Such  are  the  effects  of  rachitis,  a  disease  of  which  the  nature  is  well 
understood,  though  we  are  not  the  better  informed  with  regard  to  the 
manner  in  which  its  causes  operate,  or  the  medicines  which  it  requires. 

The  vertebral  column  forms  the  truly  essential  aud  fundamental  part 
of  the  skeleton;  it  may  be  considered  as  the  base  of  the  osseous  edifice, 
as  the  point  in  which  all  their  efforts  terminate,  as  the  centre  on  which 
all  the  bones  rest  in  their  various  motions;  since  every  effort  or  shock,  in 
any  way  considerable,  is  felt  there.  Moreover,  it  contains  in  the  canal 
with  which  it  is  perforated,  the  cerebral  prolongation,  which  furnishes 
most  of  the  nerves  in  the  body. 

In  order  that  it  may  support  all  the  different  parts  and  at  the  same  time, 
protect  the  delicate  organ  which  it  contains*,  and  adapt  itself  to  the  va- 
rious attitudes  required  by  the  wants  of  life,  it  was  necessary  that  the 
vertebral  column  should  possess,  besides  great  solidity,  a  sufficient  degree 
of  mobility;  it  possesses  both  these  advantages,  and  owes  the  former  to 
the  breadth  of  the  surfaces  by  which  its  bones  are  articulated  together, 
to  the  size,  the  length,  the  direction,  and  the  strength  of  their  processes, 
and  to  the  great  number  of  muscles  and  ligaments  connected  with  it:  it 
owes  its  freedom  of  motion  to  the  great  number  of  bones  of  which  it  is 
formed.  Each  single  vertebra  has  but  a  slight  degree  of  motion,  but  as 
they  all  have  the  power  of  moving  at  once,  the  sum  of  their  individual 
motion  added  together,  gives  as  the  result  a  general  motion  which  is 


'*  The  peculiar  manner  in  which  the  vertebree  grow,  is  itself  accommodated  to  the 
delicacy  of  the  spinal  marrow;  consisting-,  for  a  considerable  length  of  time,  of  several 
pieces  divided  by  cartilages,  the  circumference  of  the  opening  in  these  bones,  becomes 
enlarged,  with  the  enlargement  of  the  spinal  marrow,  as  we  grow  older.  The  circum- 
ference of  the  foramen  of  the  occipital  bone  and  that  of  the  first  vertebra  which  cor- 
respond to  the  thickest  part  of  the  spinal  marrow,  is,  on  thai,  account,  formed  of  four 
distinct  pieces  separated  by  cartilages  in  the  first  of'  these  bones,  and  of  five  pieces  in  the 
other.— ^Author'*  J\"otp. 


335 

considerable,  and  which  is  estimated  by  multiplying  the  single  motion 
by  the  number  of  vertebrae. 

The  centre  of  the  motions,  by  which  the  spine  is  extended  or  bends  for- 
ward or  backward,  is  not  situated  in  the  articulation  of  the  oblique  pro- 
cesses, as  it  is  maintained  by  Winslow,  in  the  Memoirs  of  the  Academy 
of  Sciences  for  the  yeur  1730,  nor  in  the  invertebral  substance.  The  exten- 
sion and  flexion  of  the  vertebrae  are  not  performed  in  two  centres  of  mo- 
tion, the  one  in  the  intervertebral  substance,  the  other  in  the  articulation 
of  the  articulating  processes,  as  was  imagined  by  Cheselden  and  Barthez, 
but  on  an  axis  crossing  the  bone  between  its  body  and  its  great  aperture. 
The  anterior  part  of  the  bone  and  its  spinous  process  perform,  around 
this  imaginary  axis,  motions  forming  part  of  a  circle,  and  whirh  though 
limited,  are  not  the  less  marked  ;  and  in  these  motions,  the  articulating 
surfaces  separated  by  the  intervertebral  substance  are  brought  into  close 
contact,  and  this  substance  is  compressed,  while  the  oblique  processes 
move  on  one  another,  and  tend  to  part  from  one  another:  this  is  what 
happens  in  bending  the  trunk,  while,  in  straightening  it,  the  anterior  sur- 
faces are  removed  from  each  other,  the  posterior  surfaces  approach,  come 
closer  and  closer  together,  and  finally  touch  throughout  the  whole  of 
their  extent,  when  the  extension  of  the  trunk  is  carried  as  far  as  the  spi- 
nous processes  will  allow. 

The  use  of  the  ridge  of  projections  which  arise  from  the  posterior  part 
of  the  vertebrae,  is  to  limit  the  bending  of  the  trunk  backwards,  and  to 
enable  the  muscles  which  straighten  it,  to  act  with  a  more  powerful  lever. 
When,  from  the  habit  of  an  habitually  erect  posture,  these  processes  have 
been  prevented  from  growing  in  their  natural  direction,  the  trunk  may  be 
bent  backward  to  such  a  degree,  that  the  body  forms,  in  that  direction, 
an  arc  of  a  circle.  It  is  thus,  that  they  train,  from  the  earliest  infancy, 
the  tumblers  who  astonish  us  by  the  prodigious  suppleness  of  their  loins, 
in  bending  backward  so  as  to  change  the  natural  direction  of  their  spinal 
processes. 

It  was  of  consequence,  that  the  motions  of  the  vertebral  column  should 
take  place,  at  once,  in  a  great  number  of  articulations,  as  the  curvatures 
are  thus  less  sharp,  and  thus  the  organization  of  the  spinal  marrow, 
•which  is  very  delicate,  is  not  injured.  Thefibro-cartalaginous  substances 
which  connect  together  the  bodies  of  the  vertebrae,  between  which  they 
lie,  possess  a  remarkable  degree  of  elasticity,  like  all  bodies  of  the  same 
kind,  and  support,  in  a  favourable  manner,  the  weight  of  the  body.  When 
the  pressure  which  they  experience  is  long  continued,  they  somewhat 
yield,  and  diminish  in  thickness,  and  this  effect  taking  place,  at  the  same 
time,  in  all  the  intervertebral  substance,  our  stature  is  sensibly  lowered.  The 
body  is,  on  that  account  always  shorter  in  the  evening  than  in  the  morn- 
ing, and  this  difference  maybe  considerable,  as  is  mentioned  by  Buffon  to 
have  been  the  case  in  several  instances.  The  son  of  one  of  his  most 
zealous  coadjutors  (M.  Gueneua  de  Montbeillard,  to  whom  is  due  the 
greatest  part  of  the  natural  history  of  birds,)  a  young  man  of  tali  stature, 
five  foot  nine  inches  when  he  had  reached  his  complete  growth,  once  lost 
an  inch  and  a  half,  after  spending  a  whole  night  at  a  ball.  This  differ- 
ence in  the  stature  depends,  likewise,  on  the  condensation  of  the  cellular 
adipose  tissue  at  the  heel,  which  forms,  along  the  whole  of  the  sole  of 
the  foot,  a  pretty  thick  layer. 

The  thigh  bone  is  longer  in  man  than  in  quadrupeds,  and  this  relative 


336 

length  of  the  thigh,  gives  him  exclusively  the  power  of  resting  his  body 
by  sitting. 

The  tibia  is  the  only  one  of  the  bones  of  the  leg  which  affords  a  support 
to  the  body.  The  fibula,  situafed  at  its  outer  part,  too  thin  and  slender  to 
support  the  weight  of  the  body,  is  of  use  merely  with  regard  to  the  arti- 
culation of  the  foot,  on  the  outside  of  which  it  lies.  It  supports  the  foot, 
and  prevents  its  starting  outward  by  too  powerful  an  abduction.  The 
foot,  in  this  motion,  is  forced  against  the  fibula  which  is  bent  outwardly, 
the  more  so  when  the  person  is  advanced  in  years,  and  has,  therefore, 
called  into  frequent  action  this  force  of  resistance.  Animals  that  climb, 
as  the  squirrels  whose  feet  are  in  a  continual  state  of  abduction,  have  a 
rvery  large  and  strongly  curved  fibula*. 

The  number  of  the  parts  which  form  the  feet,  besides  giving  to  these 
parts  a  greater  solidity,  is  further  useful  in  preventing  the  foot  from 
being  too  violently  shaken  by  striking  the  ground,  in  our  various  motions 
of  progression.  In  leaping  from  a  height,  we  endeavour  to  fall  on  our 
toes,  that  the  force  of  the  fall  may  be  broken,  by  being  communicated  to 
the  numerous  articulations  of  the  tarsus  and  the  metatarsus,  and  may  not 
affect  the  trunk  and  head  with  a  painful  and  even  dangerous  concussion. 
It  is  well  known,  that  when,  in  falls,  the  whole  soal  of  the  foot  strikes 
against  the  ground,  fracture  of  the  neck,  of  the  thigh  bones,  and  concus- 
sion of  the  brain  and  other  organs,  is  not  an  unlikely  consequence. 

CLXXVI.  Structure  of  the  bones.  Whatever  difference  there  may  at 
first  sight,  seem  to  exist,  between  a  bone  and  another  organ,  their  compo- 
sition is  the  same.  Its  structure  consists  of  parts  that  are  perfectly  si- 
milar, with  the  exception  of  the  saline  inorganic  matter  which  is  deposi- 
ted in  the  cells  of  its  tissue,  which  gives  it  hardness  and  that  solidity 
which  constitutes  the  most  striking  difference  that  distinguishes  it  from 
the  soft  parts.  This  earthy  substance  may  be  separated,  by  immersing  the 
bone  in  nitrie  acid  diluted  in  a  sufficient  quantity  of  water.  It  is  then 
found,  that  it  is  a  phosphate  of  lime  which  is  decomposed,  by  yielding 
to  the  nitric  acid  its  calcareous  base.  The  bone,  thus  deprived  of  the 
principle  to  which  it  owes  its  consistence,  becomes  soft,  flexible,  and  re- 
sembles a  cartilage,  which  is  resolvable,  by  long  maceration,  into  a  cel- 
lular tissue  similar  to  that  of  the  other  parts.  This  tissue  contains  a 
considerable  number  of  arteries,  veins,  and  lymphatics.  The  bones 
are,  therefore,  mere  cellular  parenchymas  whose  areolse  contain  a  crys- 
tallized saline  substance,  which  they  separate  from  the  blood,  and  with 
which  they  become  incrusted,  by  a  power  inherent  in  their  tissue,  and 
peculiar  to  it.  The  same  result  may  be  obtained  by  inverting  the  analy- 
sis. If  a  bone  be  exposed  to  boiling  heat,  for  a  few  hours,  in  Papin's  di- 
gester, all  its  organized  parts  become  dissolved,  melt  and  furnish  a  quan- 
tity of  gelatine,  after  which  there  remains  only  an  inorganic  saline  con- 

•  This  curvature  is  well  marked  in  the  chief -d'ceuvre  of  antique  sculpture,  and  gives 
to  the  lower  part  of  the  leg,  in  our  most  beautiful  statues,  a  thickness  which  does  not 
at  all  agree  with  our  present  notions  of  elegance  of  form.  This  seems  to  me  to  prove, 
that  the  beautiful  is  not  invariable,  as  has  been  asserted  by  many  philosophers  ;  and 
that  ideal  perfection  is  not  precisely  the  same  in  all  ages,  in  nations  equally  civilized. 
The  truth  of  this  observation  may' be  proved  by  the  Apollo  Belvidere  ;  his  knees  are 
rather  large  and  close  tog-ether,  and  this  form  is  the  most  beautiful  representation  of 
Nature,  which  gives  to  the  femur  an  obliquity  inwards,  the  knees  not  being  perfectly 
straight,  and  without  any  disproportion  between  the  calf  and  the  thin  part  of  the  leg. — 
Author's  Note. 


337 

cretion  ;  which  may,  likewise,  be  obtained  in  a  separate  state,  calcining 
the  osseous  part.  The  different  proportions  of  the  saline  to  the  organized 
part,  vary  considerably  at  different  periods  of  life  :  the  bones  of  the  em- 
bryo are,  at  first,  quite  gelatinous.  At  the  period  of  birth,  and  during  the 
first  years  of  life,  the  organic  part  of  the  bone  is  in  greater  proportion  ; 
the  bones  are  less  apt  to  break,  more  flexible,  possessed  of  more  vitality, 
and,  when  fractured,  are  more  speedily  and  more  easily  consolidated,  In 
youth,  the  two  constituent  parts  are  nearly  in  equal  quantities;  in  adults, 
the  calcareous  earth*  alone  forms  two  thirds  of  the  osseous  substance. 
At  last,  gradually  increasing  in  quantity,  it  displaces,  in  old  people,  the 
part  that  is  organized  :  hence  their  bones  are  weaker,  more  liable  to  frac- 
ture, and  unite  less  readily.  One  may  therefore  say,  that  the  quantity  of 
phosphate  of  lime  deposited  in  the  bones,  is  in  the  direct  ratio  of  the  age; 
and  that,  on  the  contrary,  the  energy  of  the  vital  faculties  of  these  or- 
gans, their  flexibility,  their  electricity,  their  aptitude  to  become  conso- 
lidated, when  their  continuity  is  destroyed  by  accidents,  are  in  an  inverse 
ratio. 

Anatomists  distinguish  in  bones  three  substances,  which  they  term 
compact,  spongy,  and  reticular.  The  first,  which  is  the  hardest,  collect- 
ed in  the  centre  of  the  long  bones,  where  the  greatest  stress  of  the  efforts 
applied  to  their  extremities  rests,  gives  to  the  bone  the  strength  which  it 
required.  Its  formation  has  been  explained,  in  various  ways;  some  have 
maintained  that  it  owed  its  hardness  to  the  pressure  applied  to  its  middle 
part  by  the  tv/o  extremities  of  the  bone  ;  in  the  same  manner  as  the  stalk 
and  the  roots  press  against  the  collet^  of  a  plant.  Haller  thinks  it  is  caused 
by  the  pulsations  of  the  nutritious  arteries  which  penetrate  into  the  long 
bones,  at  their  middle  part;  why  then  is  their  structure  different  at  their 
extremities  where  they  receive  arteries  equally  large  and  more  numerous? 
In  the  process  of  ossification,  this  substance  appears  first  in  the  centre  of 
the  longbonesj;  and  this  confirms  the  assertion  of  Kerkringius,  whosays, 
that  our  long  bones  begin  to  ossify,  in  those  points  where  they  have  to 
resist  the  greatest  pressure. 

The  spongy  substance  is  found  within  the  short  bones,  and  at  the  ex- 
tremities of  the  long  ones,  where'its  accummulation  is  attended  with  two 
advantages,  that  of  giving  to  the  bone,  without  increasing  its  weight,  a 
considerable  size,  by  which  it  may  be  articulated  with  the  neighbouring 
bones,  by  wide  surfaces,  so  as  to  give  firmness  to  their  connexions;  this 
confirmation  is  attended  with  another  advantage,  that  of  avoiding  the  pa- 
rallelism of  the  tendons  which  pass  over  the  joints,  in  order  to  enlarge 
the  angle  of  their  insertion  in  the  bones,  and  to  give  more  efficacy  to  mus- 
cular action.  The  mechanical  hypotheses  proposed  by  Haller  and  Du- 
hamel,  to  explain  the  formation  of  this  spongy  substance,  are  very  unsatis- 
factory, especially  if  it  be  considered,  that  in  the  gelatinous  bones  of  the 
embryo,  the  place  that  is  to  be  occupied  by  the  spongy  substance,  viz. 
the  extremities  of  the  long  bones,  of  which  the  rudiments  begin  to  ap- 


*  By  chemical  analysis  of  the  bones,  there  have  been  discovered  several  other  saline 
substances  mixed  with  the  phosphate  of  lime  ;  but  as  this  salt  alone  constitutes  the 
greatest  part  of  the  substance  which  gives  to  the  bones  their  hardness,  it  has  been  par- 
ticularly adduced.     For  an  account  of  the  chemical  constitution  of  the  osseous,  texture, 
see  the  Chapter  at  the  end  ot  the  APPENDIX — Copland. 

f  The  part  where  the  stem  joins  the  root. — Trans. 

*  See  APPENDIX,  Note  H  H 

2  U 


338 

pear,  are  larger  than  any  other  part.  All  the  cells  of  this  spongy  sub- 
stance communicate  with  one  another,  they  are  lined  by  a  very  fine  mem- 
brane, and  contain  the  medullary  fluid.  The  lamina  which  cross  each 
other,  in  various  directions,  and  which  form  the  parietes  of  the  cells,  be- 
come fewer  in  number,  and  thinner;  the  spongy  tissue  expands  in  ap- 
proaching the  middle  part  of  the  bones,  and  forms  (within  the  medullary 
canal,  of  the  compact  substance)  a  reticular  tissue,  the  use  of  which  is 
to  support  the  membranous  tube  containing  the  marrow. 

These  three  substances,  notwithstanding  their  unequal  denstiy,  are,  in 
reality,  but  one  and  the  same  substance  differently  modified.  The  reticu- 
lar and  spongy  differ  from  the  compact,  in  containing  less  phosphate  of 
lime,  and  in  having  rarer  and  more  expanded  tissue.  In  other  respects, 
those  changes  in  the  osseous  tissue  which  constitute  the  laminated  exos- 
toses,  the  conversion  of  the  bones,  by  acids,  into  a  flexible  cartilage, 
which,  by  maceration,  may  be  reduced  into  cellular  tissue,  prove  that  these 
three  substances  are  truly  identical,  and  differ  from  each  other  only  by 
the  degrees  of  closeness  of  their  texture  and  the  quantity  of  calcareous 
phosphate  deposited  in  the  meshes  of  their  tissue. 

The  compact  substance  appears  to  consist  of  concentric  lamina  strong- 
ly united  together,  and  to  be  formed  of  fibres,  arranged  longitudinally, 
and  in  juxta  position.  In  proof  of  this  arrangement,  it  is  usual  to  men- 
tion the  exfoliation  of  bones  to  the  air;  but  these  lamina  detached  from 
an  exfoliating  bone,  merely  prove  that  the  action  of  the  disease,  the  air, 
heat,  or  any  other  agent,  by  applying  itself  successively  to  the  different 
layers  of  bone,  produces  between  a  separation  which  did  not  exist  in 
health,  and  determines  their  falling  off  in  succession.  Certain  parts,  in 
which  this  lamellated  structure  does  not  exist,  may,  in  like  manner,  un- 
dergo the  same  kind  of  decomposition.  Thus,  Lassone  saw  a  piece  of 
human  skin  that  had  been  preserved,  for  a  considerable  length  of  time 
in  a  vault,  separate  into  layers  of  extreme  minuteness. 

The  vital  principle  which  exists,  in  a  smaller  degree,  in  the  bones  than 
in  other  parts,  seems  to  animate,  to  a  certain  degree,  their  different  sub- 
stances. Proportioned  to  the  number  of  vessels  which  arc  distributed 
to  it,  life  is  more  active  in  the  spongy  tissue;  hence,  in  fracture  of  this 
part,  fleshy  granulations  and  callus  form  more  quickly.  Caries,  like- 
wise advances  more  rapidly,  and  it  is  more  difficult  to  interrupt  its 
progress. 

CLXXVII.  Of  the  uses  vf  the  jieriosteum  and  of  the  medullary  juices. 
Whatever  be  the  situation,  the  size,  the  shape^  and  the  composition  of 
bones,  they  are  all  eveloped  by  the  periosteum,  a  whitish,  fibrous,  dense 
and  compact  membrane,  to  which  are  distributed  the  vessels  which  pe- 
netrate into  their  substance.  The  periosteum  is  a  membrane  perfectly 
distinct  from  the  other  soft  parts,  and  from  the  bone  itself,  to  which  it 
adheres  by  means  of  vessels  and  of  cellular  tissue,  which  pass  from  the 
one  to  the  other,  the  more  closely,  as  we  are  advanced  in  years.  The 
cellular  and  vascular  fibres  which  penetrate  into  the  substance  ofthe  bone, 
establish  a  very  close  sympathetic  connexion  between  its  periosteum  and 
the  very  delicate  membrane  that  lines  its  internal  cavity,  which  secretes 
the  marrow,  and  is  called  the  internal  periosteum.  On  destroying  the 
internal  medullary  membrane,  by  introducing  a  stylet  within  the  cavity 
of  the  bone,  its  external  layers  swell,  are  detached  from  the  inner  ones, 
and  form,  as  it  were,  anew  bone  around  the  sequestra.  The  new  bone  is 
not  formed  by  the  ossification  of  the  periosteum,  as  was  maintained  by 


339 

Troja.  This  membrane  has  no  more  to  do  with  the  formation  of  the 
new  bone,  in  necrosis,  than  with  that  of  the  callus  in  fracture*.  The  pe- 
riosteum, covering  a  bone  affected  with  necrosis,  does  not  become  thick- 
er, and  does  not  acquire  more  consistence  ;  nor  is  there  formed  around 
the  ends  of  a  fractured  bone,  a  ring  to  keep  them  cemented,  as  was  the 
opinion  of  Duhamel ;  an  opinion  recently  brought  forward  in  a  work  in 
which  the  author  seems  to  delight  in  reviving  errors  that  have  been  aban- 
doned for  ages.  Destitute  of  nourishment,  (lead  and  dried  up  in  this  ar- 
tifical  necrosis,  the  sequestra  moves  in  the  centre  of  the  new  osseous 
production,  from  which  it  may  be  extracted  by  a  perforation  made  for 
that  purpose.  It  is  owing  to  the  same  sympathy,  that  the  dull  noc- 
turnal pains  which  are  occasioned  by  the  warmth  of  the  bed,  in  patients 
in  the  last  stages  of  the  venereal  affection,  and  which  appear  to  have  their 
seat  in  the  centre  of  the  long  bones,  occasion  a  swelling  of  these  bones 
and  of  the  periosteum. 

The  use  of  the  periosteum  is  to  regulate  the  distribution  of  the  nutri- 
tious juices  of  bones,  since,  whenever  it  is  removed,  granulations  arise, 
in  an  irregular  manner,  on  the  spot  that  is  bared.  This  quality  is,  be- 
sides, common  to  all  fibrous  membranes  whose  destruction  is  followed  by 
excrescences  from  the  organs  which  they  cover.  The  same  take  place, 
whenever  trees  are  partially  stripped  of  their  bark.  It  has  been  errone- 
ously believed,  that  the  periosteum,  in  the  same  way  as  the  bark  of  plants, 
contributes  to  the  growth  of  the  bones,  by  the  successive  induration  of 
its  internal  lamina. 

The  marrow  which  tills  the  central  cavity  of  the  long  bones  ;  and  the 
medullary  fluid  contained  in  the  cells  of  the  spongy  substance,  bear  the 
greatest  analogy  to  adeps,  both  in  their  chemical  composition  and  in  their 
uses  (CVI.)  The  proportion  of  these  two  fluids  is  uniformly  relative.^— 
In  very  thin  people,  the  bones  contain  a  marVow  that  is  thin  and  watery, 
and  though  this  fluid  always  fills  the  internal  cavities  of  these  .organs, 
whose  solid  parietes  cannot  collapse,  it  contains  much  fewer  particles  in 
the  same  bulk  ;  and  its  quantity  like  that  of  the  fat,  is  in  fact  diminished. 
It  is  the  product  of  arterial  exhalation,  and  does  not  serve  to  the  imme- 
diate nutrition  of  the  bone,  as  was  thought  by  the  ancients  ;  at  least,  it 
does  not  answer  the  purpose  solely,  for,  in  the  numerous  class  of  birds, 
the  bones  contain  cavities  for  air,  and  are  destitute  of  this  fluid.  It  is  dif- 
ficult to  determine  the  use  of  the  marrow  and  of  the  medullary  fluid  : 
may  they  not  answer  the  purpose  of  filling  the  cavities  which  Nature  has 
formed  in  the  bones,  so  as  to  render  them  lighter  ?  Does  a  part  of  these 
fluids  exude  through  the  cartilages  of  the  joints,  and  mix  with  the  syno- 
via to  increase  its  quantity:  and  to  lessen  the  friction  of  the  articulating 
surfaces  ?  If  this  transudation  may  take  place  after  death,  why  might  it 
not  take  place,  when  all  the  parts  are  in  a  state  of  vital  warmth  and  ex- 
pansion! ? 


*  The  manner  in  which  the  new  bone  acquires  a  periosteum,  in  cases  of  the  regene- 
ration of  this  texture,  is  a  matter  of  much  interest  and  doubt.  In  the  examination  of 
some  specimens,  Dr.  Knox  observed  a  thin  membrane  covering1  the  osseous  granulations; 
but  he  knew  of  no  facts  to  decide  whence  the  membrane  proceeds.  "  It  is  not  unlike- 
ly," he  remarks,  "that  it  is  supplied  by  the  cellular  texture  either  of  the  new  bone,  or 
of  the  surrounding-  parts  ;  and  that  in  some  instances  it  may  be  merely  a  prolongation  of 
the  old.  New  skin  on  ulcers  does  not  always  grow  from  the  surrounding1  healthy  edg- 
es : — which  fact  may  be  applied  to  the  formation  of  new  periosteum." — Copland. 

f  The  marrow  of  the  bones  is  contained  in  the  medullary  membrane.     This  latter  sub- 


340 

CLXXVIII.  Of  the  articulations,  the  articulating  cartilages  and  liga- 
ments^ and  the  synovial  fluid.  The  articulations  of  the  different  parts  of 
the  skeleton  are  not  all  intended  to  allow  of  motion,  several,  as  the  ser- 
rated and  squamous  sutures,  and  the  gomphosys,  are  entirely  without 
motion,  and  are,  on  that  account,  termed  synarthrosis.  All  the  other  ar- 
ticulations, whether  the  bones  are  in  immediate  contact  (diarthrosis  of 
contiguity,)  whether  they  are  united  by  a  substance  interposed  between 
them  (diarthrosis  of  continuity  or  amphiarthrosis,)  are  endowed  with  a 
certain  degree  of  mobility.  I  shall  speak  merely  of  the  moveable  articu- 
lations ;  whether  they  allow  of  extensive  motions  and  in  every  direction 
(diarthrosis  orbicularis,)  or  whether  the  bones  move  only  in  two  opposite 
directions  (alternate  diarthrosis  or  ginglymus,)  by  forming  an  angle  (an- 
gular ginglymus,)  or  by  executing,  on  each  other,  motions  of  rotation 
(lateral  ginglymus.) 

In  all  the  articulations,  the  osseous  surfaces  are  covered  by  lamina  of 
a  substance  less  hard  than  that  of  the  bone.  These  are  the  articulating 
cartilages  which  answer  the  two  purposes  of  giving  to  the  ends  of  the 
bones,  the  degree  of  polish  necessary  to  their  slipping  freely,  and  to  fa- 
cilitate motion,  by  the  considerable  degree  of  elasticity  which  they  pos- 
sess. Morgagni  has  shown,  that  of  all  animal  substances,  cartilages  pos- 
sess most  elasticity  ;  their  sturucture  is  very  different  from  that  of  the 
bones,  even  when  these  are  yet  cartilaginous;  for,  these  articulating  car- 
tilages do  not  become  ossified,  even  in  persons  greatly  advanced  in 
years*.  They  are  formed  of  very  short  fibres  disposed  according  to  the 
length  of  the  bone,  strongly  compressed  against  each  other,  and  united 

stance  may  be  easily  detached  from  the  bone.  It  resembles,  in  some  respects,  a  cob- 
web, being  pierced  by  a  number  of  holes.  It  is  formed  of  cellular  tissue,  and  of  vessels. 
The  former  is  very  delicate  and  rare  ;  and  evidently  performs  the  function  of  furnish- 
ing a  surface  for  the  ramification  of  the  vessels.  Some  of  these  vessels  are  ramified  ex- 
ternally, proceeding  directly  from  the  medullary  membrane  to  the  osseous  texture  sur- 
rounding' it,  and  thus  performing  the  office  of  an  internal  periosteum  to  the  bone; — 
others  are  distributed  internally,  and  in  the  direction  of  the  axis  or  the  bone,  to  the  me- 
dullary membrane  itself,  and  to  the  spongy  extremities  of  the  bones.  The  principal 
artery  of  the  medullary  canal  is  surrounded  by  absorbent  vessels  at  its  entrance  into  this 
canal.  A  plexus  of  nerves  may  be  also  observed  to  surround  the  artery  in  the  same  situ- 
ation, and  to  dip  into  the  bone  at  the  place  nearest  to  the  arterial  trunk. 

The  adipose  vesicles,  which  contain  the  marrow  and  occupy  the  interior  of  the  medul- 
lary membrane,  are  the  same  in  kind  as  those  of  the  cellular  texture,  although  less  dis- 
tinct. Authors  have  long  since  considered  that  those  adipose  vesicles  are  united  en 
grappt,  and  may  believe  that  they  communicate  with  eacli  other. 

M.  BECXAKD  considers  the  marrow  to  consist  of  seven  parts  out  of  eigl it  of  an  oleagin- 
ous matter,  in  fat  subjects,  which  inference  accords  with  the  opinion  of  of  GUUTZMACHEII; 
while  this  substance,  in  a  phthisical  patient,  was  found  to  consist  of  only  a  fourth  part 
of  fatty  matter,  the  rest  being  a  serous,  or  albuminous-like  fluid. 

The  marrow  does  not  exist  in  the  fostus,  and  even  the  medullary  mebrane  itself  can- 
not be  recognised  previous  to  ossification.  As  this  process  advances,  the  medullary  ca- 
nal begins  to  be  formed  ;  and  at  first  the  nutritious  artery  nearly  fills  it.  At  a  later  pe- 
riod this  artery  is  seen  ramified  on  the  parietes  of  this  cavity,  and  in  the  situation  of  the 
medullary  membrane.  The  marrow  becomes  abundant  as  age  advances,  owing  to  the 
enlargemeut  of  the  medullary  cavity. 

The  sensibility  of  the  marrow,  which  was  contended  for  by  DCRVSRIVEY,  but  since  de- 
nied, is  considered  by  M.  BKCLARD  really  to  exist,  and  to  be  satisfactorily  shown,  when 
some  time  is  allowed  to  ellipse  between  the  pain  of  the  operation  necessary  to  expose 
the  marrow,  and  the  experiment  to  which  it  is  to  be  subjected. 

See  APPKNDIX,  Note  H  H,  for  additional  remarks  on  this  subject. —  Copland. 

*  Sometimes,  however,  these  cartilages  are  destroyed,  the  denuded  bone  then  becomes 
polished  by  friction,  and  as  hard  as  ivory.  —  Copland. 


341 

by  other  transverse  fibres.  This  verticle  direction  of  the  greatest  pan 
of  cartilaginous  fibres,  demonstrated  by  Lassone,  is  very  favourable  to 
their  elastic  re-action.  The  capsular  ligament  is  reflected  over  them,  be- 
comes very  thin,  and  is  lost  in  their  perichondrium,  according  to  Bonn, 
Nesbit,  and  other  anatomists. 

Besides  the  cartilages  which  surround  the  extremities  of  bones,  there 
are  found,  in  certain  articulations,  fibre-cartilaginous  lamina  lying  be- 
tween the  articulating  surfaces.  These  connecting  ligaments  may  be  ob- 
served in  the  articulation  of  the  lower  jaw  to  the  temporal  bones,  of  the 
femur  with  the  tibia,  and  of  the  sternum  with  the  clavicle  ;  and  all  such 
articulations  perform  a  great  number  of  motions,  as  is  the  case  with  the 
jaw,  or  suffer  considerable  pressure,  as  the  joints  of  the  knee  and  sternum. 
The  latter,  which  has  a  very  slight  degree  of  motion,  being  the  point  in 
which  terminate  all  the  efforts  of  the  upper  extremity,  required  this  ap- 
paratus to  lessen  the  effect  on  the  trunk,  the  motion  that  is  given,  being 
in  part,  lost,  in  the  action  of  the  articulating  cartilage*. 

I  shall.'not  repent  what  has  been  already  said  of  the  secretion  of  the  fluid 
that  lubricates  the  articulating  surfaces,  that  facilitates  their  motion,  and 
keeps  them  in  contact.  Its  quantity  is  in  direct  ratio  to  the  extent  of 
these  surfaces,  and  of  the  membranous  capsule  in  which  they  are  contain- 
ed ;  it  is  likewise,  proportioned  to  the  frequency  of  motion  which  each 
articulation  allows. 

Synovia  is  the  name  that  is  given  to  the  fluid  prepared  by  the  glandule- 
cellular  bodies  in  the  vicinity  of  the  articulations,  and  secreted  by  the 
membranous  capsules  which  surround  them,  and  are  reflected  over  the 
articulating  extremities  of  the  bones  whose  cartilages  they  cover ;  so  that, 
as  was  shown  by  Bonn,  about  the  middle  of  the  last  century,  these  extre- 
mities cannot  be  said  to  be  contained  within  the  cavity  of  the  capsule, 
which  is  closed  in  every  direction,  any  more  than  the  abdominal  viscera 
within  that  of  the  peritoneum.  The  synovia  is  heavier  than  common  wa- 
ter, quite  cojourless,  and  more  viscid  than  any  other  animal  fluid.  It 
contains  a  considerable  quantity  of  albumine,  which,  according  to  Mar- 
gueron,  who  first  gave  a  tolerably  accurate  analysis  of  synovia,  it  is  found 
in  a  particular  state,  and  much  disposed  to  concrete  in  to  filaments,  on  the 
addition  of  acids. 

Besides,  it  contains  muriate  and  carbonate  and  phosphate  of  lime, 
the  whole  dissolved  in  water,  which  forms  about  three-fourths  of  its 
weightf. 

CLXXIX.  Theory  of  Anchylosis.  Motion  may  be  considered  as  the 
proper  stimulus  of  the  synovial  secretion;  and  a  moveable  joint,  as  is  just- 
ly observed  by  Grimaud,is  as  a  centre  of  fluxion  towards  which  the  fluids 
rush,  in  every  direction,  in  consequence  of  the  irritation  which  friction 
determines.  If  the  joint  remains  long  without  motion,  the  synovia  is  se- 
creted in  smaller  quantity,  and  this  lessens  gradually  :  it  may  even  hap- 


*  The  most  certain  proof  of  the  organic  nature  of  the  cartilages  is  the  serous  exuda- 
tion which  appears  in  the  course  of  a  few  seconds  after  a  clean  division  of  them  by  the 
knife.  Cellular  texture  forms  the  mould  or  basis  in  which  the  cartilaginous  substance  is 
deposited.  The  vessels  of  this  texture  carry  only  the  colourless  part  of  the  blood  into 
it,  during  its  ordinary  state  of  health;  yet  it  is  remarkable  that  other  colouring  substan- 
ces, as  bile  and  madder,  give  this  substance  their  respective  colours — Copland. 

|  See  the  Chapter  on  the  Chemical  Constitution  of  the  Secretions,  &c.  at  the  end  of 
the  ApBExmx. —  Copland. 


342 

pen  that  the  articulating1  surfaces  remaining  long  and  absolutely  motion* 
less,  lose  their  moisture,  and  from  the  want  of  the  fluid  which  should  lu- 
bricate .them,  bring  on  irritation  and  adhesive  inflammation  in  each  other, 
either  from  increased  action  of  the  vessels  of  the  perichondrium,  or 
as  is  believed  by  Nesbit,  Bonn,  and  others,  from  an  inflammatory  state 
of  the  fold,  which  is  reflected  from  the  capsule  ot  the  joint  over  the  liga- 
ment. 

This  is  the  manner  in  which  the  disease,  termed  anchylosis,  comes  on, 
a  disease  improperly  ascribed  to  the  congestion  of  the  soft  parts,  and  es- 
pecially of  the  ligaments  surrounding  the  articulations.  In  fact,  when  in 
a  fracture  of  the  thigh  or  leg,  about  the  middle  of  the  length  of  one  of 
these  bones,  and  consequently,  at  the  greatest  possible  distance  from  the 
knee  joint,  the  circumstances  of  the  case  require  that  the  bandages  should 
be  kept  on  the  limb,  a  considerable  time,  the  joint  loses  its  power  of  mo- 
tion, recovers  it  with  difficulty,  and  sometimes  not  at  all.  I  have  at 
present  before  me,  the  case  of  a  man  in  whom  a  scorbutic  affection  has 
delayed,  to  such  a  degree,  the  union  of  the  bone,  after  a  simple  fracture 
of  the  femur,  about  the  middle  of  the  bone,  that  it  has  been  found  neces- 
sary to  continue,  for  seven  months  the  use  of  splints.  In  the  course  of  so 
long  a  state  of  inaction,  the  soft  parts  have  lost  the  habit  of  moving,  and 
the  knee  is  almost  completely  ancholysed. 

Whenever,  on  account  of  any  complaint,  one  has  been  confined  to  bed, 
the  first  attempts  to  walk  are  painful,  difficult,  and  attended  by  a  marked 
crepitus  in  the  knee,  denoting  clearly  the  want  of  synovia.  On  the  other 
hand,  if  the  joint  is  examined  in  a  person  who  before  death  has  been 
Jong  without  motion,  the  articulating  surfaces  will  be  found  rough  and 
dry,  with  evident  marks  of  iuflammation.  Flajani  mentions  the  case  of  a 
patient  who  died  after  having  been  three  months  in  bed,  in  an  almost  mo- 
tionless state.  Externally,  the  knees  did  not  appear  to  have  been  injur- 
ed, and  yet  he  could  not  bend  his  knee  joint.  On  opening  the  joint,  it 
was  found  that  the  articulating  surfaces  had  grown  together ;  the  poste- 
rior part  of  the  patella  adhered  to  the  condyles  of  the  femur,  and  it  was 
necessary  to  use  a  scalpel  to  detach  these  parts  from  each  other.  I  have 
frequently  observed  the  same  appearance  in  dissecting  the  knee  joint  of 
persons  who  died  while  labouring  under  white  swelling,  with  or  without 
ulceration.  The  anchylosis  which  invariably  attends  this  affection,  evi- 
dently arises  from  the  absolute  rest  of  the  diseased  joint. 

Anchylosis  from  want  of  motion,  and  consequently  from  want  of  syno- 
via, is  not  always  a  partial  affection  limited  to  one  or  two  joints ;  some- 
times, it  affects  several  at  once,  as  in  the  case  of  the  patient  whose  skele- 
ton was  presented  by  M.  Larrey  to  the  museum  of  the  School  of  Medi- 
cine at  Paris.  One  of  the  most  remarkable  cases. of  universal  anchylosis 
of  the  joints,  is  that  lately  communicated  to  the  National  Institute  by  M. 
Percy;  the  patient  was  an  old  cavalry  officer,  who  was  subject  to  fits  of 
the  gout,  and  whose  articulations,  even  that  of  the  lower  jaw,  became  stiff 
and  completely  lost  all  power  of  motion,  so  that,  towards  the  latter  end  of 
hiy  wretched  existence,  he  could  notbe  moved  without  feeling  severe  pain 
in  his  ancholysed  joints. 

From  this  explanation  may  be  conceived  the  advantage  of  moving  the 
lower  extremity,  when,  after  a  fracture  of  the  leg,  the  ends  of  the  bone 
have  become  sufficiently  united  lo  prevent  their  being  displaced.  These 
motions,  which  are  of  indispensable  necessity  in  all  fractures  of  the  fe- 
mur, of  the  tibia,  and  especially  of  the  patella,  are  much  better  calculated 


343 

to  prevent  anchylosis,  than  the  various  resolvent  remedies  which  are  com- 
monly employed,  as  plasters  of  soap,  vigo,  cicuta,  drabotanum, diachylon, 
pumping,  bathing,  and  fumigations,  which,  however,  should  be  used  in 
combination  with  a  moderate  exercise  of  the  limb,  in  order  to  obtain  the 
most  complete  success. 

The  gout  affects  those  joints  whcih  are  most  subject  to  motion,  and  on 
which  there  is  the  greatest  pressure.  The  first  attacks,  as  Sydenham 
observes,  come  on  in  the  joint  of  the  great  toe  with  the  first  metatarsal 
bone,  an  articulation  which  bears  the  weight  of  the  whole  body,  and 
which  is  most  called  into  action,  in  the  various  motions  of  progression. 

The  muscles  which  pass  over  the  joints  give  them  much  greater  secu- 
rity than  the  lateral  ligaments.  In  fact,  if  the  muscles  become  palsied, 
the  mere  weight  of  the  limb  stretches  the  ligaments,  which  give  way  be- 
come elongated,  and  allow  the  head  of  the  bone  to  escape  from  its  gle- 
noid  cavity.  It  is,  in  this  manner,  that  a  loss  of  motion,  and  atrophy  of 
deltoid  muscle,  are  attended  with  a  luxation  of  the  humerus:  the  orbicu- 
lar ligament  of  the  articulation  of  this  bone  with  the  scapula,  being  in- 
capable of  retaining  its  head  within  the  glenoid  cavity.  The  spinal 
column,  when  dissected  and  deprived  of  all  but  its  ligamentous  attach- 
ments, gives  way  under  a  weight  much  smaller  than  that  which  it  would 
have  supported,  before  being  stripped  of  the  muscles  which  are  connect- 
ed with  it. 

CLXXX.  Of  standing.  This  is  the  name  given  to  the  action  by  which 
man  holds  himself  upright  on  a  solid  plane.  In  this  erect  position  of  all 
our  parts,  the  perpendicular  line  passing  through  the  centre  of  gravity* 
of  the  body,  must  fall  on  some  point  of  the  space  measured  by  their  soals 
of  the  feet.  Standing  is  most  firm  when  on  prolonging  the  line  of  the 
centre  of  gravity  of  the  body,  it  falls  on  the  base  of  sustentation  (I  call 
thus  the  space  defined  by  the  feet,  whether  close  or  apart;)  but  this  line 
may  tend  to  exceed  it,  without  our  necessarily  falling,  the  muscular  ac- 
tion soon  restoring  the  equilibrium  which  is  deranged  by  the  altered  di- 
rection of  this  line.  But  if  the  lower  extremity  of  the  line,  by  being  pro- 
longed, should  fall  without  the  limits  of  the  base  of  sustentation,  a  fall  is 
unavoidable  on  the  side  towards  which  this  line  inclines!. 

If  the  body  is  inclined  backwards,  so  that  there  is  a  danger  of  a  fall  on 
the  occiput,  the  extensor  muscles  of  the  leg  contract  powerfully,  to  pre- 
vent the  thigh  from  bending,  while  other  powers  bring  forward  the  up- 
per parts,  and  give  to  the  prolonged  line  of  the  centre  of  gravity  a  differ- 
ent direction;  and  if  in  proportion  as  the  extensors  of  the  leg  are  brought 
into  action,  its  inclination  be  increased  to  such  a  degree  that  nothing  is 
capable  of  keeping  up  the  body,  which  its  own  weight  tends  to  bring  to 
the  ground,  these  muscles,  by  a  motion  proportioned  to  the  quickness  of 
the  fall,  will  increase  their  efforts  to  prevent  it,  and  may  be  able,  in  that 
violent  contraction,  to  snap  asunder  the  patella,  as  I  have  explained  in  a 
Memoir  on  the  fractures  of  that  bone. 


*  The  centre  of  gravity,  in  the  adult,  is  situated  between  the  sacrum  and  pubis. 

f  ' '  Quotiescitmque  linea  propensionis  coi^poris  humani  ccu<:t  t>xtra  WMIS  peitis  innixi 
plantam,  out  extra  yuadrilaUrum,  comprehension  a  ditabus  plantis  pedum,  impediri  ndna, 
a  q-uocumquK  musculorwn  coaatu,  non  potest."  Borelli.  Prop.  140. 

The  firmness  of  the  attitude,  in  standings,  depend,  therefore,  in  part,  on  the  breadth 
of  the  feet  and  on  their  distance  ;  hence,  it  is  much  more  tottering  when  we  stand  on 
one  foot,  and  we  are,  under  such  circumstance,  obliged  to  be  perpetually  struggling-, 
to  prevent  the  centre  of  gravity  from  falling  out  of  the  narrow  limits  of  the  base  of  sus- 
tentation — Author's  Note, 


344 

I  think  it  useful  to  insist,  more  than  has  been  done  hitherto,  on  the  me- 
chanism by  which  the  human  body  is  supported  in  the  erect  posture;  for 
a  knowledge  of  that  mechanism  facilitates  the  explanation  of  the  motions 
of  progression.  To  walk,  or  to  run,  the  body  must  be  upright;  now, 
•when  it  is  known  by  what  power  the  centre  of  gravity  of  the  body  is  main- 
tained perpendicular  on  the  plane  which  supports  it,  it  will  be  easy  to 
understand  the  different  ways  in  which  it  changes  its  place,  in  the  course 
of  locomotion. 

Let  us  first  inquire  into  the  question  so  long  agitated,  whether  man  la 
intended  to  support  himself  and  to  walk  on  his  four  limbs,  in  the  early 
period  of  his  existence  after  birth  ? 

CLXXXI.  An  upright  position  would  be  to  man  a  state  of  rest,  if  his 
head  were  in  a  perfect  equilibrum  on  the  vertebral  column,  and  if  the 
latter^  forming  the  axis  of  the  body  and  supporting  equally,  in  every  di- 
rection, the  weight  of  the  abdominal  and  thoracic  viscera,  fell  perpen- 
dicularly on  the  pelvis  placed  horizontally,  and,  in  short,  if  the  bones  of 
the  lower  extremities  formed  columns  set  perpendicularly  under  their 
superincumbent  weight;  but  not  one  of  these  circumstances  is  to  be  ob- 
served in  the  human  body:  the  articulation  of  the  head  docs  not  corres- 
pond to  its  centre  of  gravity;  the  weight  of  the  thoracic  and  abdominal 
viscera,  and  of  the  parietes  of  the  cavities  in  which  they  are  contained, 
rests,  almost  entirely,  on  the  anterior  part  of  the  vertebral  column.  The 
vertebral  column  is  supported  on  an  inclined  base,  and  the  bones  of  the 
inferior  extremities,  which  are  connected  to  each  other  by  convex  and 
slippery  surfaces,  are,  more  or  less,  inclined  towards  one  another.  It  is 
therefore  necessary,  that  an  active  power*  watch  incessantly,  to  prevent 
the  fall  which  would  be  the  natural  consequences  of  their  weight  and 
direction. 

This  power  resides  in  the  extensor  muscles  which  keep  the  parts  of 
OUP  body  in  a  state  of  extension,  the  more  perfect,  and  which  render  our 
erect  posture  the  firmer,  as  they  are  endowed  with  a  more  considerable 
power  of  antagonism,  and  as  our  parts  arenaturally  less  disposed  to  flexion; 
and,  besides,  as  we  have  seen  (CLXVI.)  these  powers  are  not  sufficient 
to  balance  those  whose  action  is  directly  opposed  to  theirs. 

The  relative  weakness  of  the  extensor  muscles  is  not  the  only  obstacle 
which  renders  impossible  an  erect  posture,  at  an  early  period  of  life. 
Other  causes,  into  which  we  are  about  to  enter,  concur  in  unfitting  the 
new  born  child  for  the  exercise  of  that  faculty. 

The  articulation  of  the  head  to  the  vertebral  column  being  nearer  the 


*  An  upright  posture  is  not,  in  all  animals,  as  it  is  in  man,  the  consequence  of  an 
effort.  This  is  proved  by  the  following  fact,  observed  by  M.  Dumeril.  The  sea  fowl, 
and  especially  the  waders  (Grallae,  Lin.)  as  the  herons  and  storks,  forced  to  live  in  the 
midst  of  marshes  and  muddy  waters,  in  which  they  find  the  fishes  and  reptiles,  on  which 
they  feed,  have  long  since  afforded  matter  of  surprise  to  Naturalists,  by  the  length  of 
time  they  can  remain  motionless  in  an  erect  posture.  This  singular  power,  so  necessary 
to  animals  obliged  to  expect  their  prey,  mure  from  change  than  from  industry,  they  owe 
to  a  peculiar  conformation  of  the  arliculation  between  the  leg-  and  the  thigh.  The  arti- 
culating surface  of  the  thigh  bone,  as  M.  Dumeril  had  an  opportunity  of  observing- in  a 
stork  (Ardea  ciconia,  Linn.)  contains,  in  its  centre,  a  depression,  into  which  there  is  re- 
ceived a  projection  of  the  tibia.  To  enable  the  animal  to  bend  its  leg,  that  projection 
must  be  disengaged  from  the  depression  into  which  it  is  lodged,  and  this  is  resisted  by 
several  ligaments  which  keep  the  leg  extended  in  standing,  in  flying,  and  other  progres- 
sive motions,  without  the  assistance  of  the  extensor  muscles. —  Copland. 


.345 

occiput  than  the  chin,  and  not  corresponding*  to  its  centre  of  gravity,  its 
own  weight  is  sufficient  to  make  it  fall  on  the  upper  part  of  the  chest.  It 
is  the  more  disposed  to  fall  forward,  from  its  greater  bulk,  and,  as  in  a 
new  born  child  the  head  is  much  larger  in  proportion  than  the  other  parts 
of  the  body,  and  as  its  extensor  muscles  partake  of  the  greater  weakness 
of  that  set  of  muscles,  it  falls  on  the  fore  part  of  the  chest,  and  its  fall 
draws  the  body  after  it.  The  weight  of  the  thoracic  and  abdominal  vis- 
cera tends  to  produce  the  same  effect. 

Growth  always  proceeds  from  the  upper  to  the  lower  parts,  and  this 
law,  which  operates  uniformly,  completely  eludes  every  kind  of  mechani- 
cal explanation.  It  is  otherwise,  with  regard  to  the  effects  which  result 
from  this  unequal  growth  in  respect  to  the  erect  posture.  The  inferior 
limbs,  which  serve  as  a  base  to  the  whole  edifice  being  imperfectly 
evolved  at  the  period  of  birth,  the  upper  parts  placed  on  these  unsteady 
foundations  must  necessarily  fall  and  bring  them  down  with  them. 

The  relative  weight  of  the  head,  of  the  thoracic  and  abdominal  viscera, 
tends,  therefore,  to  bring  forwards  the  line  in  the  direction  of  which  all 
the  parts  of  the  body  press  on  the  plane  which  supports  it,  and  this  line 
should  be  exactly  perpendicular  to  that  plane  to  enable  the  body  to  be 
perfectly  erect:  the  following  fact  proves  this  assertion:  I  have  observed, 
that  children,  whose  head  is  very  large,  whose  belly  projects,  and  Whose 
viscera  are  loaded  with  fat,  have  much  difficulty  in  learning  to  stand;  it 
is  only  about  the  end  of  their  second  year,  that  they  dare  trust  to  their 
own  strength,  and  then  they  meet  with  frequent  falls,  and  have  a  con- 
tinual tendency  to  go  on  all  fours. 

The  vertebral  column,  in  the  child,  does  not  describe,  as  in  the  adult, 
three  curves  alternately  placed,  in  opposite  directions.  It  is  almost 
straight,  and  yet  presents  in  the  direction  of  its  length  a  slight  curvature, 
the  concavity  of  which  looks  forwards.  This  incurvation,  which  depends 
solely  on  the  flexion  of  the  trunk  while  ;ri  the  womb,  is  accordingly  more 
marked,  the  nearer  the  child  is  to  the  time  of  its  birth. 

It  is  well  known  that  the  curvatures,  in  opposite  directions  to  the  ver- 
tebral column,  add  to  the  firmness  of  the  erect  posture,  by  increasing  the 
extent  of  the  space  within  which  the  centre  of  gravity  may  move,  without 
being  carried  Jbeyond  its  limits.  With  regard  to  that  use,  the  vertebral 
column  may  be  considered,  as  defined  by  two  lines  drawn  from  the  ante- 
rior and  posterior  part  of  the  first  cervical  vertebra,  to  the  sacro  lum- 
bar symphysis.  These  two  lines,  very  near  to  each  other  at  their  upper 
part,  and,  below,  at  a  distance  from  each  other,  would  be  the  chords  of 
arcs  and  the  tangents  of  the  curves,  formed  by  the  vertebral  column. 
So  that  this  column  may  be  considered  as  having  a  fictitious  thickness 
greatly  exceeding  its  real  bulk. 

In  the  new-born  child,  the  want  of  alternate  curvatures  not  only  con- 
tracts the  boundaries  within  which  the  centre  of  gravity  may  be  varied, 
but  the  direction  of  the  only  curvature  which  exists  favours  the  flexion 
of  the  trunk,  and  consequently  the  inclination  forward  of  the  centre  of 
gravity,  and  the  tendency  to  fall  in  that  direction.  This  inflexion  of  the 
vertebral  column  in  the  foetus  and  in  the  young  child,  resembles  that  ob- 
served in  several  quadrupeds*. 


*  This  curvature  is  very  distinctly  marked  in  swine.     The  back  of  these  animals  is 
remarkably  prominent,  and  this  form,  necessary  to  enable  the  vertebral  column  to  sup- 

2X    ' 


34$ 

The  disadvantages  resulting  from  the  want  of  alternate  curvatures  in 
the  vertebral  column  of  the  child,  is  further  increased,  by  the  total  ab- 
sence of  spinous  processes.  It  is  well  known,  that  the  principal  use  of 
these  projections,  is  to  place  the  power  at  a  distance  from  the^  centre  of 
motion  of  the  vertebrae,  to  increase  the  length  of  the  lever  by  which  it 
acts  in  straightening  the  trunk,  and  thereby  to  render  its  action  more  effi- 
cacious. At  the  period  of  birth,  the  vertebrae  have  no  spinous  processes, 
they  afterwards  grow  from  the.  place  at  which  the  lamina  of  those  bones 
are  united,  by  means  of  a  .cartilaginous  substance,  which  completes 
the  posterior  part  of  the  vertebral  canal.  The  muscles  destined  to  keep 
the  trunk  erect,  weakened  by  its  constant  flexion  during  gestation,  lose, 
besides,  a  great  deal  of  their  power,  from  the  unfavourable  manner  in 
which  they  are  applied  to  the  part  on  which  they  .are  to  act. 

The  flexion  of  the  head  does  not  depend  merely  on  its  very  considerable 
\veight,  but,  likewise,  on  the  want  of  spinous  processes  in  the  cervical 
vertebrae;  since  the  principal  motions  of  the  neck  are  performed,  not  so 
much  by  articulation  with  the  atlas,  as  by  union  of  the  other  cervical 
vertebrae. 

The  pelvis  of  the  child  is  but  imperfectly  evolved,  and  its  upper  outlet 
very  oblique.  The  viscera,  which  are  afterwards  to  be  contained  within 
its  cavity,  are,  for  the  greater  part,  situated  above  it.  This  obliquity  of 
the  pelvis  would  require  a  perpetual  straightening  of  the  vertebral  column 
to  prevent  the  direction  of  the  centre  of  gravity  from  obeying  its  natural 
tendency  forward.  On  the  other  hand,  the  vertebral  column  resting  on  a 
narrow  pelvis,  is  less  firmly  fixed,  and  may  more  readily  be  drawn  beyond 
the  limits  of  the  base  of  sustentation.  Lastly,  the  limited  extent  of  the 
pelvis,  together  with  its  obliquity,  causes  the  ill  supported  abdominal 
viscera  to  fall  on  the  anterior  and  inferior  part  of  the  parietes  of  the  ab- 
domen, and  favours  the  fall  of  the  body  in  the  same  direction. 

The  patella,  which  answers  the  double  purpose  of  giving  firmness  to 
the  knee  joint,  in  front  of  which  it  is  placed,  and  of  increasing  the  power 
of  the  muscles  of  the  leg,  by  placing  them  at  a  distance  from  the  centre  of 
motion  in  that  articulation,  and  by  increasing  the  angle  at  which  they  are 
inserted  into  the  tibia,  as  yet  does  not  exist  in  new-born  children.  The 
tendinous  portion  of  the  leg,  where  the  patella  is  hereafter  to  be  formed, 
is  merely  of  a  more  condensed  tissue,  and  of  a  cartilaginous  hardness. 

The  want  of  a  fulcrum  is  attended  with  a  continual  disposition  in  the 
leg  to  bend  upon  the  thigh,  and  the  parallel  direction  of  its  extensor 
muscles,  occasions  a  complete  loss  of  their  effective  power.  Then  their 
antagonizing  muscles  induce  a  flexion  of  that  limb,  which  is  the  more 
considerable,  as  it  is  but  imperfectly  limited  by  the  tendon  which  is  situ- 
ated at  the  fore  part  of  the  knee. 

The  length  of  the  os  calcis,  the  extent  of  its  projection  beyond  the  in- 
ferior extremity  of  the  bones  of  the  leg,  tend  to  give  firmness  to  the 
erect  posture,  by  increasing  the  length  of  the  lever  by  which  the  ex- 
tensors of  the  foot  act  on  the  heel,  and,  as,  in  the  new-born  child,  this 
bone  is  shorter  and  less  projecting,  the  power  of  these  muscles,  whose 

port  the  immense  vv eight  of  their  abdominal  viscera,  has  a  considerable  influence  on 
the  mechanism  of  their  motions  of  progression.  When  frif  htened  by  any  noise,  they 
spring  in  bounds ;  and  it  is  easy  to  perceive,  that,  at  each  spring",  the  spine  becomes 
arched  and  then  .straightens  itself,  and  that  their  motion  when  rapidjs  effected  by  the 
alternate  tension  and  relaxation  of  their  spinal  column. — JLuthvr's  Note. 


347 

insertion  is  very  near  the  centre  of  motion  of  the  articulation  of  the  foot, 
is  greatly  diminished. 

The  feet,  in  man,  are  broader  than  those  of  any  other  animal;  and  to 
this  breadth  of  the  surface  of  the  base  on  which  he  rests,  he,  in  great 
measure,  owes  the  advantage  of  being  able  to  support,  on  one  leg  or  on 
both,  the  weight  of  his  body,  in  standing  and  in  the  different  motions  of 
progression ;  while  ,the  other  mammalia  cannot  support  themselves,  at 
least  only  for  a  very  limited  time,  without  resting  on  three  of  their  extre- 
mities. When  I  say,  that  from  the  extent  of  the  feet  the  body  of  man 
does,  of  all  animals,  rest  on  the  broadest  surface,  I  do  not  take  into  ac- 
count the  space  which  those  parts  include  between  them  when  apart  from 
each  other.  In  fact,  the  space  which  is  measured  by  the  feet,  is  much 
greater  in  quadrupeds  than  in  man.  Nature  has  made  up  for  the  disad- 
vantage arising  out  of  the  smallness  of  their  feet,  by  the  distance  at  which 
they  are  placed ;  and  if  that  farm  disables  them  from  standing  on  two 
feet,  it  gives  firmness  to  their  peculiar  mode  of  standing. 

The  feet  of  the  ourang  outang,  which,  in  the  general  structure  of  his 
organs,  bears  so  striking  an  analogy  to  the  human  species,  resemble  a 
coarsely  formed  hand,  better  fitted  to  climb  the  trees  on  which  that  ani- 
mal seeks  his  food,  than  to  the  purposes  to  which  man  applies  his  hands. 
Thus,  the  erect  posture  which  he,  at  times,  assumes,  is  neither  the  most 
convenient  nor  the  most  natural  to  him.  And,  according  to  a  philosopher 
who  speaks  on  the  authority  of  several  travellers,  if  a  sudden  danger 
obliges  him  to  make  his  escape,  or  to  leap,  he  drops  on  all  fours,  and  dis- 
covers his  real  origin:  he  is  reduced  to  his  own  condition,  when  he  quits 
that  unnatural  attitude,  and  discovers  in  himself  an  animal,  which,  like 
many  a  man,  has  no  better  quality  to  recommend  him  than  a  specious 
disguise. 

The  feet  are  the  parts  least  developed  in  the  new-born  child;  his  body 
is  insecure  on  that  narrow  basis;  the  prolongation  of  the  line  of  his  centre 
of  gravity,  which  so  many  other  causes  tend  to  carry  beyond  that  base, 
will  be  the  more  inclined  to  fall  beyond  it,  from  its  small  extent.  The 
greater  number  of  the  differences  which  have  just  been  examined,  depend 
on  the  mode  of  nutrition  in  the  foetus.  The  umbilical  arteries  bring  to 
the  mother  the  blood  which  the  aorta  carries  to  the  lower  parts,  and  only 
a  few  small  branches  are  sent  to  the  pelvis  and  to  the  lower  extremities. 
Thus,  the  developtment,  which  almost  always  bears  a  proportion  to  the 
the  quantity  of  blood  sent  into  organs,  is  but  imperfect  in  those  parts  at 
the  time  of  birth,  while  the  head  of  the  trunk  and  upper  extremities  are 
enveloped  much  more  considerably. 

The  new-born  child,  therefore,  resembles  quadrupeds  in  the  physical 
arrangement  of  his  organs.  This  analogy  is  the  more  marked,  the  nearer 
the  foetus  is  to  the  period  of  its  formation,  and  it  might  be  laid  down  as 
a  general  proposition,  that  organized  beings  resemble  one  another  more 
closely,  the  nearer  to  the  period  of  incipient  existence  they  are  examined. 
The  differences  which  characterise  them  become  apparent,  in  proportion 
to  the  progress  of  evolution;  and  they  are  more  and  more  distinct,  as  the 
acts  of  life  are  repeated  in  the  organs  which  it  animates. 

The  unequal  distribution  of  power  in  the  muscles,  and  the  unfavoura- 
ble disposition  of  the  parts  to  which  these  powers  are  applied,  render  it 
impossible  for  the  infant  to  stand  upright,  that  is,  to  keep  the  mean  line 
of  direction  of  his  body  nearly  perpendicular  to  the  plane  which  supports 
it.  But  in  proportion  as  he  advances  in  age,  the  preponderance  of  the 


348 

flexors  over  the  extensors  ceases  to  be  in  excess.  The  proportionate  size 
of  the  head  and  of  the  thoracic  abdominal  viscera  diminishes.  The  cur- 
vatures of  the  vertebral  column  begin  to  be  distinguishable,  the  spinous 
processes  of  the  vertebrae  are  evolved;  the  breajdth  of  the  pelvis  is  in- 
creased, and  its  obliquity  lessened;  the  patella  becomes  ossified,  the  os 
calcis  juts  out  backwards,  the  relative  smallness  of  the  feet  ceases.  By 
degrees  the  child  learns  to  stand,  resting  on  both  or  only  on  one  of  his 
feet;  his  eyes  natu tally  directed  towards  heaven,  a  noble  prerogative, 
which,  if  one  might  believe  Ovid*,  is  possessed  by  man  alone  of  all  the 
animals. 

Man  is  of  all  animals  the  only  one  that  can  stand  upright  and  walk  in 
that  attitude,  when  his  organs  are  sufficiently  evolved.  Let  us  now  point 
out  some  of  the  principal  causes  to  which  that  privilege  is  to  be  ascribed. 

CLXXXII.  Though  the  articulation  of  the  head  to  the  cervical  column 
does  not  correspond  either  to  its  centre  of  magnitude,  or  to  its  centre  of 
gravity,  and  though  it  is  nearer  to  the  occiput  than  to  the  chin,  its  dis- 
tance tfrom  the  latter  is  much  smaller  in  man,  than  in  the  monkey  and 
other  animals,  whose  foramen  magnum  is,  according  to  Daubenton, 
placed  nearest  to  the  posterior  extremity  of  the  head,  when  they  resem- 
ble man  the  least.  The  head,  therefore,  is  very  nearly  in  equilibrio  on 
the  column  which  supports  it;  at  least  to  keep  it  in  that  position,  a  very 
slight  power  is  required,  while  the  head  of  a  quadruped,  which  has  a 
constant  tendency  towards  the  ground,  requires  to  be  supported  by  a  part 
capable  of  a  great  and  continued  resistence.  This  purpose  is  answered 
by  the  posterior  cervical  ligament,  so  remarkable  in  those  animals,  at- 
tached to  the  spinous  processes  of  the  vertebrae,  and  to  the  protuberance 
of  the  occipital  bone,  which  projects  much  more  in  them  than  in  the 
human  species,  in  whom  instead  of  the  posterior  cervical  ligament,  there 
is  found  a  mere  line  of  cellular  substance,  dividing  the  nape  of  the  neck 
into  two  equal  parts. 

The  alternate  curvatures  of  the  vertebral  column,  the  breadth  of  the 
pelvis  and  of  the  feet,  the  great  power  of  the  extensors  of  the  foot  and 
thighf,  all  these  favourable  conditions,  observable  in  man,  are  wanting  in 
animals;  but,  as  in  the  latter,  every  thing  concurs  to  prevent  their  be- 
ing capable  of  standing  on  two  feet,  in  man  every  thing  is  so  disposed, 
as  to  render  it  very  difficult  for  him  to  rest  on  his  four  extremities.  In 
fact,  independently  of  the  great  inequality  which  there  is  between  his  up* 
per  and  lower  limbs,  a  difference  of  length  which,  being  less  sensible  in 
early  life,  makes  it  less  uneasy  for  a  child  to  walk  on  his  hands  and  feet, 
these  four  limbs  are  far  from  affording  the  body  an  equally  solid  support. 
The  eyes  being  naturally  forwards,  are,  in  that  attitude,  directed  towards 
the  earth,  and  do  not  embrace  a  sufficient  space. 

We  cannot,  therefore,  agree  with  Barthez,  that  man,  during  infancy, 
is  naturally  a  quadruped,  since  he  is  then  but  an  imperfect  biped ; 


*  Os  he-mini  sublime  dedit,  calwnque  tueri 
Jnssi:,  et  ereclos  ad  sidtra  toll-re  vultus. 

These  verses  may  be  much  more  justly  applied  to  the  fish,  called  by  naturalists  Uran- 
oscopus.  Its  eyes  are  turned  \ip\vards,  and  constantly  look  towards  the  heavens. — Au- 
thor's JV0fe. 

j-  These  masses  form  the  calf  of  the  leg  and  the  buttocks ,  in  no  animal  are  these 
muscles  more  prominent  than  in  man. 


349 

(CLXXXI.)  nor  can  we  admit  that  man  might  walk  on  all  fours  all  his 
lite,  if  he  were  not  broken  of  the  bad  habit  which  he  learns  in  infancy. 

CLXXXII1.  Very  little  has  been  added  to  what  Galen  has  said  in  his 
admirable  work  of  the  structure  of  parts,  relative  to  the  respective  ad- 
vantages attending  the  peculiar  conformation  and  structure  of  the  upper 
and  lower  limbs.  It  is  easy  to  see,  that  in  combining,  as  much  as  pos- 
sible, strength  and  facility  of  motion,  Nature  has  made  the  former  pre- 
dominate in  the  structure  of  the  inferior  extremities,  while  she  has  sacri- 
ficed strength  to  facility,  to  precision,  to  extent,  and  rapidity  of  motion, 
in  the  upper  extremities. 

To  convince  one's  self  of  the  truth  of  what  has  been  stated,  it  is  suffi- 
cient to  compare,  under  the  two  relations*  of  the  resistance  of  which 
they  are  capable,  and  of  the  motions  which  they  allow,  the  pelvis  to  the 
shoulder,  the  thigh  to  the  humerus,  the  leg  to  the  fore  arm,  and  the  foot 
to  the  hand. 

The  inferior  extremities,  if  examined  when  the  bones  are  covered  with 
the  soft  parts,  will  present  the  appearance  of  an  inverted  cone  or  pyramid, 
which,  at  first  sight,  appears  contrary  to  the  object  which  Nature  had  in 
view;  but  if  the  bones  be  stripped  of  their  fleshy  coverings,  these  solid 
supports  will  be  seen  to  represent  a  pyramid,  whose  base  is  at  the  lowest 
part,  and  formed  by  the  foot,  and  which  decreases  in  breadth  upward 
from  the  leg,  formed  by  the  union  of  two  bones,  towards  the  thigh,  con- 
sisting of  only  one  bone. 

If  it  be  asked  why  the  inferior  extremities  are  formed  of  several  pieces, 
detached  and  placed  one  above  the  other,  it  will  be  found  that  they  are 
thereby  much  more  solid,  than  if  formed  of  one  bone,  since,  according  to 
a  theorem,  demonstrated  by  Eulerf  two  columns  containing  the  same 
quantity  of  matter,  and  of  equal  diameter,  have  each  a  solidity  in  inverse 
ratio  of  the  squares  of  their  height;  in  other  words,  of  two  columns, con- 
taining the  same  materials,  of  equal  diameter,  and  of  unequal  height,  the 
smaller  is  the  stronger. 

The  long  bones,  which  by  their  union  form  the  inferior  extremity,  con- 
lain  a  cavity  which  adds  to  their  strength,  for,  according  to  another  theo- 
rem, explained  by  Galileo,  two  hollow  columns  of  the  same  quantity  of 
matter,  of  the  same  weight  and  length,  bear  to  each  other  a  proportion  of 
strength  measured  by  the  diameter  of  their  internal  excavations. 

The  breadth  of  surface  of  the  articulations  of  the  inferior  extremities, 
assists,  materially,  in  giving  them  additional  strength,  when  in  standing^ 
these  bones  are  in  a  vertical  direction.  No  articulation  has  a  broader 


*  See  the  anatomical  observations  on  the  neck  of  the  thigh  bone,  which  I  have  pre- 
fixed to  a  memoir  which  bears  the  title  of  Dissertation  anatorrdco-chimrgicale  sur  Ics  frac- 
tures du  col  de  femur.  Paris  an  VII. 

•}•  J\lelhodiis  inrt-.nientli  Eneas  citrvas. 

Nature  has,  therefore,  increased  the  number  of  these  columns  in  the  extremities  of 
quadrupeds,  by  raising  their  heel  and  the  different  parts  of  the  foot,  whose  bones  she 
has  lengthened,  to  make  of  them  so  many  secondary  legs.  These  numerous  columns 
placed  above  one  another,  are  alternately 'inclined,  and  in  a  state  of  habitual  flexion,  in 
the  quadrupeds  remarkable  for  swiftness  in  running,  or  for  their  power  in  leaping,  as  in 
the  hare  and  squirrel,  while  in  the  ox,  and  especially  in  the  elephant,  they  are  ,all  placed 
vertically,  so  that  the  enormous  mass  of  the  latter  rests  on  four  pillars,  the  different 
pieces  of  which  are  short,  and  so  slightly  moveable  on  one  another,  that,  as  Barthex. 
observes,  Saint  Basil  has  adopted  the  error  of  Pliny,  JElian,  and  several  other  wri- 
ters of  antiquity,  that  there  are  no  articulations  in  the  legs  of  that  monstrous  animal- 
— Author's  Note. 


350 

surface  than  that  of  the  thigh  with  the  leg  and  knee-pan.  Among  the 
orbicular  articulations,  no  one  has  more  points  of  contact  than  the  joint 
of  the  thigh  bone  to  those  of  the  pelvis.  Professor  Barthez  says,  that 
when  the  body  is  erect,  the  head  of  the  thigh  bone  and  the  acetabulum  of 
the  os  innominatum,  which  receives  that  bone,  come  in  contact  in  a  sur- 
face of  small  extent.  I  am,  on  the  contrary,  of  opinion,  that  in  no  pos- 
sible case  can  the  contact  of  two  bones  be  more  complete.  The  middle 
line  of  direction  of  the  upper  part,  the  thigh  bone,  is  then  exactly  perpen- 
dicular to  the  surface  of  the  comlyloid  cavity,  which  embraces  and 
touches,  in  nearly  every  point,  the  almost  spherical  head  of  that  bone. 

The  cervix'on  which  the  head  of  the  bone  is  placed,  by  keeping  the 
thigh  bone  at  a  distance  from  the  cavity  of  the  pelvis,  increases  the  ex- 
tent of  the  space,  in  which  the  centre  of  gravity  may  vary  without  being 
carried  beyond  its  limits. 

CLXXXIV.  The  erect  posture  does  not  imply  a  perfect  absence  of 
motion.  It  is  on  the  contrary,  accompanied  by  a  staggering,  which  is 
the  more  marked  in  proportion  as  the  person  has  less  strength  and  vig- 
our.— These  perpetual  oscillations,  though  but  slightly  distinct,  in  a  man 
who  stands  upright,  depend  on  the  incapacity  of  the  extensors  to  keep 
up  a  constant  state  of  contraction,  so  that  they  become  relaxed  for  a  short 
time,  and  the  intervals  of  rest  in  the  extensors  are  frequent,  in  proportion 
to  the  weaker  state  of  the  subject. 

Some  physiologists  have  given  a  very  inaccurate  idea  of  standing,  by 
making  that  attitude  depend  on  a  general  effort  of  the  muscles  ;  the  ex- 
tensors only  are  truly  active.  The  flexors,  far  from  assisting,  tend,  on 
the  contrary,  to  disturb  the  relation  between  the  bones,  necessary  to  ren- 
der that  state  permanent.  This  explains,  why  standing  is  so  much 
more  fatiguing  than  walking,  in  which,  the  extensors  and  flexors  of  the 
limbs,  are  in  alternate  action  and  rest. 

It  may  be  said,  nevertheless,  that  to  give  the  greater  firmness  to  the 
attitude,  we  sometimes  contract,  in  a  moderate  degree,  the  flexors  them- 
selves ;  then,  that  great  part  of  the  real  force  of  the  muscles,  which  acts 
according  to  the  direction  of  the  levers  which  they  are  to  set  in  motion 
(CLXVI.)  and  which  rs  completely  lost  in  the  different  motions  which 
they  produce,  is  usefully  employed  in  drawing  together  the  articular  ex- 
tremities, in  keeping  their  surfaces  firmly  applied  to  each  other,  and  in 
maintaining  their  exact  superposition  which  is  necessary  to  the  erect 
posture  of  the  body.  No  one  that  I  know  of,  had  taken  notice  of  this 
employment  of  the  greater  portion  of  our  muscular  power,  which  was 
thought  completely  lost  by  the  unfavourable  arrangement  of  our  organs 
of  motion.  The  line,  according  to  which  all  the  parts  of  the  body  bear 
on  the  plane  which  supports  them,  has  much  more  tendency  to  fall  for- 
wards than  backwards*;  and  falls  forward  are  the  most  common  and 
the  easiest.  Thus,  nature  has  directed,  in  the  same  direction,  the  mo- 
tion of  the  hands,  which  we  carry  forward  to  break  the  force  of  our  falls, 
to  prevent  too  violent  shocks^  and  to  lessen  their  effect.  At  the  same 
time,  she  has  provided  means  of  protection  towards  the  sides  which  the 


*  This  tendency  is  much  less  distinct  in  tall  slender  men.  It  is  observed,  that  they, 
for  the  most  part,  stoop  in  walking,  less  from  the  habit  of  bending- forward,  than  to  pre- 
vent the  centre  of  gravity  from  falling-  behind.  Pregnant  women,  dropsical  patients, 
all  persons  who  have  much  corpulence  throw  their  body  back,  from  an  opposite  and 
easily  understood  reason. — Copland. 


kands  couid  not  guard.  She  has  given  more  thickness  to  the  back  part 
of  the  skull;  the  skin  which  covers  the  neck  and  back,  is  much  denser 
than  that  which  covers  the  fore  part  of  the  body.  The  scapula,  in  addi- 
tion to  the  ribs,  protects  the  posterior  part  of  the  chest.  The  spinal 
column  lies  along  the  whole  length  of  the  back ;  the  bones  of  the  pelvis 
have  their  whole  breadth  turned  backward. 

Falls  are  the  more  serious,  as  they  occur  in  a  more  perfect  statew  of 
extension  of  the  articulations;  the  falls  of  a  child  whose  limbs  are  in  an 
fiabitual  state  of  flexion,  are  much  less  dangerous  than  those  of  a  strong 
and  powerful  adult,  whose  body  falls  in  one  piece,  if  I  may  be  allowed 
that  expression.  The  falls  which  skaiters  meet  with,  on  the  ice,  are  often 
fatal  from  fracture  of  the  skull,  which,  placed  at  the  extremity  of  a  long 
lever  formed  by  the  whole  body,  whose  articulations  are  on  the  stretch, 
strikes  the  slippery  and  solid  ice,  with  a  momentum  increased  by  the 
quickness  of  the  fall. 

We  have  already  seen,  that  wading  fowls  remain  a  long  while  standing, 
without  effort,  by  means  of  a  peculiar  contrivance  in  the  articulation  ot' 
the  tibia  to  the  thigh  bone,  but  all  other  birds  are  obliged  to  employ  mus- 
cular action  when  standing,  except  during  sleep.  The  greater  part,  it  is 
well  known,  roost  on  a  branch  which  they  grasp  firmly  with  their  claws. 
Now,  this  constriction,  by  which  they  cling  to  their  support,  is  a  neces- 
sary result  of  the  manner  in  which  the  tendons  of  the  flexors  of  their  feet 
descend  along  their  legs.  Tnese  tendons  pass  behind  the  articulation 
of  the  heel;  a  muscle  which  arises  from  the  pubis  joins  them,  as  it  passes 
in  front  of  the  knee,  so  that  the  bird  has  but  to  give  way  \p  his  weight, 
and  the  joints,  becoming  salient  on  the  side  along  which  the  tendons  run, 
stretch  and  pull  them,  and  make  them  act  upon  the  feet,  so  as  to  draw  in 
the  claws  to  clasp  tightly  the  braneh  on  which  he  is  perched.  Borelli 
was  the  first  who  understood  distinctly  and  explained  satisfactorily  this 
phenomenon*. 

CLXXXV.  Although  standing  on  both  feet  is  most  natural  to  man,  he 
is  able  to  stand  on  one  ;  but  the  posture  is  fatiguing,  from  the  forced  in- 
clination of  the  body  to  the  side  of  the  leg  which  supports  him,  and  the 
effort  of  contraction  required  to  keep  up  this  lateral  inflexion.  The  dif- 
ficulty increases,  if,  instead  of  resting  on  the  entire  soal,  we  choose  to 
stand  on  the  heel  or  on  the  toe:  the  base  of  support  is  then  so  small,  that 
no  effort  is  sufficient  to  keep  the  centre  of  gravity,  long  together,  in  the 
requisite  situation. 

As  to  the  degree  of  separation  of  the  feet,  which  gives  the  firmest  pos- 
sible stand,  it  depends  upon  their  length.  When  they  inclose  a  perfect 
square,  that  is,  when  taking  their  length  at  nine  inches,  each  side  of  the 
quadrilateral  figure  is  of  that  measure,  the  stand  is  the  firmest  that  can 
be  conceived.  Nevertheless,  we  are  far  from  keeping  or  taking  this  pos- 
ture to  prevent  falls.  The  wrestler  who  wants  to  throw  his  antagonist, 
strides  much  more;  but  then,  he  loses  on  one  side  what  he  gains  on  ano- 
ther ;  and  if  he  stride  thirty-six  inches,  on  the  transversal  line,  it  will 
need  much  greater  force  to  overthrow  him  on  that  side  ;  but  it  will  take 
much  less  to  throw  him  forwards,  or  on  his  back.  Wherefore,  one 
of  the  great  principles  of  this  gymnastic  art,  is  to  bring  back  the  feet 

T)e  motu  dnimaUum,  Prop.  150.   Qn&rimr  qitare  aves  stando,  ranus  arborum  compre. 
hemis,  qui-esrnnt  et  dormiunt  absquc  ruina.     Tab.  II.  fig.  7- 


to  a  moderate  stride,  in  the  line  of  the  effort  which  is  foreseen  to  require 
resistance. 

There  is  some  resemblance  to  standing,  in  the  attitudes  of  kneeling 
and  sitting. 

In  the  first,  the  weight  of  the  body  bears  upon  the  knees,  and  we  must 
bring  back  the  body,  to  throw  the  centre  of  gravity  over  the  middle  of  the 
legs.  Accordingly,  if  we  have  nothing  before  us  to  lean  on,  this  posture 
is  extremely  distressing,  and  we  cannot  long  keep  it  on.  I  have  said,  in 
another  work,  that  genuflexion  rendered  monks  very  liable  to  hernia;  the 
abdominal  viscera  being  pushed  against  the  anterior  and  lower  part  of 
the  abdomen,  by  the  throwing  back  of  the  body. 

In  sitting,  the  weight  of  the  body  bearing  on  the  tuberosities  of  the 
ischia,  there  is  much  less  effort  required  than  in  standing  on  the  feet.— • 
The  base  of  support  is  much  larger ;  and  when  the  back  leans,  almost 
all  the  extensor  muscles  employed  in  standing,  are  in  action. 

CLXXXVI.  Of  Ike  recumbent  jiosture.  Decubitus.  All  the  authors 
who,  like  Borelli,  have  treated  professedly  of  the  animal  mechanism;  all 
the  physiologists,  who,  like  Haller,  have  set  forth,  in  some  detail,  the  me- 
chanism of  standing,  and  of  progression,  have  completely  passed  over  the 
consideration  of  the  human  body  in  repose,  left  to  its  own  weight,  in  ly- 
ing on  an  horizontal  plane.  The  intention  of  the  following  observations 
is  to  fill  up  this  gap.  Let  us  consider,  at  setting  out,  that  lying  on  an 
horizontal  plane,  is  the  only  posture  in  which  all  the  locomotive  muscles 
recover  the  principle  of  their  contractility,  exhausted  by  exertion.  Stand- 
ing whhout  motion,  has  only  the  appearance  of  repose,  and  the  unremit- 
ted  contractions  it  requires,  fatigue  the  muscular  organs,  more  than  the 
alternate  contractions,  by  which  the  various  motions  of  progression  are 
carried  into  effect. 

The  human  body,  stretched  on  an  horizontal  plane,  reposes  in  four  po- 
sitions ;  as  it  lies  on  the  back,  the  belly,  or  one  or  other  of  the  sides". 
The  Latin  tongue  expresses  the  first  two  situations,  by  the  terms  supine 
and  prone*-  It  has  no  particular  word  for  lying  upon  the  sidef. 

Lying  upon  the  right  side  is  the  most  ordinary  posture  of  sleep,  in 
which  we  rest  most  pleasantly,  and  longest  together.  There  are  very 
few,  except  under  constraint  of  some  faulty  organization,  who  lie  on  the 
other  side.  This  depends  on  two  causes;  when  the  body  lies  on  the  left 
side,  the  liver,  a  bulky  viscus,  very  heavy,  and  ill  steadied  in  the  right 
hypochondrium,  presses  with  all  its  weight  on  the  stomach,  and  draws 
down  the  diaphragm  :  thence  ensues  an  uneasiness,  which  hinders  long 
continuance  of  sleep,  or  disturbs  it  with  distressing  dreams :  then  the 
human  stomach  presents  a  canal  in  which  the  course  of  its  contents  is 
obliquely  directed  from  above  downwards,  and  from  left  to  right:  the 
right  or  pyloric  orifice  of  the  stomach  is  much  less  raised  than  its  left  or 
cardiac  orifice  ;  lying  on  the  right  side  favours,  therefore,  the  descent  of 
aliments,  which  to  pass  into  the  intestines,  are  not  obliged  to  ascend 
against  their  own  weight,  as  they  must,  in  lying  on  the  left  side,  i  hese 
two  anatomical  causes  exert  their  influence  on  the  generality  of  men,  and 
if  there  are  any  who  fall  into  the  habit  of  lying  on  the  left,  one  may  safe- 


*  Cubitus  supinus,  Plin.    Cubitus  pronus,  Cicer.   Cubare  in  faciem,  Juven.    Supinus 
velpronus  jucere. 

f  Dextro  vel  laevo  hterc  cubare  ;  cubitus  in  hitus.  Plin'". 


353 

ly  conjecture  some  vicious  organization,  or  some  accidental  cause,  that 
determines  them,  as  by  instinct,  to  this  posture, 

Let  us  suppose  an  effusion  of  blood,  water,  or  pus,  in  the  sac  of  the 
pleura  of  the  right  side.  The  patient  lies  on  this  side,  that  the  weight  of 
his  body  may  not  oppose  the  dilatation  of  the  sound  side  of  the  chest.-— 
The  parietes  of  this  cavity  are  not  equally  distant  from  its  axis ;  the 
pressure  of  the  body  on  the  plane  of  support,  prevents  the  separation  of 
the  ribs,  whether  as  a  mechanical  hindrance  to  the  displacement  of  these 
bones,  or  in  numbing  the  contractility  of  the  muscles  of  inspiration,  all 
more  or  less  compressed  :  Now,  as  the  healthy  lung  must  supply  the 
place  of  the  diseased,  nothing  could  be  more  in  the  way  than  to  produce, 
on  that  side,  by  a  bad  posture,  a  constraint  equal  to  that  occasioned  by 
disease,  on  the  other. 

It  has  long  been  imagined,  and  it  is  taught  still,  that,  in  thoracic  effu- 
sions, patients  lie  on  the  side  of  the  effusion,  to  hinder  the  effused  fluid 
from  pressing  on  the  mediastinum,  and  pushing  it  against  the  opposite 
lung,  of  which  it  will  constrain  the  developement.  The  following  ex- 
periments show  clearly  enough  the  error  of  such  a  supposition  : 

I  had  several  times  produced  artificial  hydrothorax,.  by  injecting  with 
water,  the  chest  of  several  bodies,  through  a  wound  in  one  of  the  sides. 
This  experiment  can  be  made,  only  on  bodies  in  which  the  lungs  are  free 
from  adhesion  to  the  parietes  of  the  chest,  and  the  number  is  smaller  than 
might  be  imagined :  you  may  introduce  in  this  way  from  three  to  four 
pints  of  water.  I  afterwards  opened  carefully  the  opposite  side  of  the 
chest:  the  ribs  removed  and  the  lung  displaced,  gave  room  to  see  dis- 
tinctly the  septum  of  the  mediastinum  stretched  from  the  vertebral  co- 
lumn to  the  sternum,  and  supporting  without  yielding,  the  weight  of  the 
liquid,  whatever  might  be  the  posture  given  to  the  body* 

It  is  for  the  sake  then,  evidently,  of  not  preventing  the  dilatation  of  the 
sound  part  of  the  respiratory  apparatus,  already  condemned  in  one  part 
to  inaction,  that  patients,  in  thoracic  effasion,  lie  constantly  on  the  side 
of  the  effusion.  It  is  for  the  same  motive,  to  which  we  may  add  that  of 
not  increasing  the  pain  by  dragging  downward  the  inflamed  pleura,  that 
patients  in  pleurisy  lie  on  the  affected  side.  The  same  thing  happens  in 
peripneumonies;  in  a  word,  in  all  diseased  affections  of  the  lungs  ant! 
parietes  of  the  chest*. 

Lying  on  the  back,  which  is  unusual  in  health^  is  natural  in  many  dis- 
eases. It  commonly  indicates  more  or  less  weakness  of  the  muscles  of 
inspiration.  The  contractile  powers  which  perform  the  dilatation  of  the 
chest,  when  affected  with  adynamia,  in  fevers  of  a  bad  character,  or  after 
extreme  fatigue,  carry  very  imperfectly  into  effect  this  dilatation.  Ne- 
vertheless, a  determinate  quantity  of  atmospherical  air  must  be  admitted, 
every  moment,  into  the  lungs,  and  the  general  weakness  would  be  in- 
creased, if  respiration  did  not  impregnate  the  blood  with  a  sufficiency  of 
oxygen  :  patients  choose,  therefore,  the  posture  which  makes  the  dilata- 
tion of  the  lungs  easiest  for  their  weakened  muscles.  The  posterior  pa- 
rietes of  the  chest,  on  which  the  body  reposes,  lying  upon  the  back,  are  al- 
most useless  in  the  expansion  of  the  cavity.  The  ribs,  which  have,  the 
centre  of  their  motions  in  their  articulations  with  the  vertebral  column, 
are  almost  immoveable  backwards,  and  the  movsableness  of  these  bones 


*  This  is  not  the  case  until  after  adhesions  of  the  pleurae  have  taken  place.— 'Copland 


354 

increases  with  the  length  of  the  lever  which  they  represent.  So  that,  no 
where  is  it  greater  than  at  the  anterior  extremity  terminating  in  the 
sternum.  Thus,  lying  on  the  back  has  the  double  advantage  of  not  con- 
straining any  of  the  muscles  of  inspiration,  and  of  not  opposing  the  mo- 
tion of  the  ribs,  except  at  that  part  where  these  bones  have  the  least  play: 
lying  on  the  back  is  one  of  the  characteristic  symptoms  of  putrid  or  ady- 
namic  fever,  of  scurvy,  and  of  all  the  diseases  of  which  debility  of  the 
contractile  parts  forms  the  principal  characteristic.  After  the  fatigue 
of  a  long  march,  or  of  any  other  continued  exertion,  we  take  this  position 
in  lying,  and  change  it,  only  when  sleep  has  sufficiently  replaced  the  loss 
of  contractility. 

Lying  on  the  belly  has  effects  directly  the  reverse.  The  expansion  of 
the  chest  is  hindered,  exactly  where  the  bony  structure  is  formed  for  the 
greatest  play  of  motion  :  the  abdominal  viscera  are  besides  pushed  up  on 
the  diaphragm,  of  which  they  resist  the  depression,  and  the  posture  is 
accordingly  unusual.  The  continuance  of  it  during  sleep  is  possible  only 
to  the  robust  5  others,  even  when  they  do  fall  asleep  in  this  posture,  soon 
awake  from  troubled  and  distressing  dreams,  under  the  agony  known  by 
the  name  of  the  night-mare.  We  sometimes  seek  this  posture  to  constrain 
respiration,  and  so  abate  inward  excitation,  in  the  ardour,  for  instance, 
of  a  febrile  paroxysm. 

The  different  postures  of  lying  having  reference  to  the  degrees  of  fa- 
cility of  respiration,  very  young  children,  and  persons  advanced  in  years, 
prefer  lying  on  the  back,  this  posture  being,  as  was  already  observed, 
the  most  favourable  to  the  motions  of  respiration.  Respiration,  like  all 
the  other  functions  of  the  animal  economy*  with  the  exception  of  the 
circulation  and  of  the  phenomena  which  immediately  depend  on  it,  re- 
quires a  kind  of  cultivation  :  it  is  but  feebly  performed  at  an  early  period 
of  life.  It  is  only  after  a  certain  number  of  years,  and  when  the  muscles 
of  respiration,  at  first  small  and  weak,  acquire  strength  from  the  very 
circumstance  of  being  called  into  frequent  action,  that  the  chest  dilates 
'with  facility,  and  that  the  lungs  enjoy  the  full  exercise  of  their  faculties. 
Until  that  period  the  enlargement  of  the  chest  and  the  dilatation  of  the 
lungs  took  place,  in  an  imperfect  manner,  the  child  was  unable,  even  by 
spitting,  to  free  itself  of  the  mucus  with  which  its  bronchias  are  apt  to 
get  filled,  and  which  render  the  pulmonary  catarrh,  called  the  hooping 
cough,  so  dangerous  at  an-  early  period  of  life.  In  like  manner,  in  an 
old  man,  the  muscles,  debilitated,  and  returned  to  t,he  relative  weakness 
of  infancy,  in  vain  strive  to  clear  the  air  ceils  of  the  mucus  with  which 
they  become  obstructed  in  the  suffocating  catarrh.  The  mechanical 
process  of  respiration  is,  therefore,  equally  difficult  in  the  child,  from 
the  weakness  of  the  muscles  which  have  remained  in  a  long  continued 
state  of  inactivity;  in  the  old  man,  from  the  debility  of  the  same  organs 
and  from  the  induration  of  the  cartilages.  Thus,  at  those  two  distant 
periods  of  life,  it  is  most  natural  to  lie  on  one's  back,  but  there  is  a  suffi- 
ciently remarkable  difference  in  that  respect,  and  which  may  now  be  in- 
quired into. 

In  the  foregoing  observations,  I  have  always  spoken  of  the  human  body 
as  stretched  on  a  perfectly  horizontal  plane.  It  is  seldom,  however,  that 
\ve  rest  on  such  a  surface,;  almost  every  one,  and  especially  persons  ad- 
vanced in  life,  require  that  the  plane  should  be  inclined,  and  that  the 
head  should  be  raised  to  a  certain  degree,  else  the  brain  would  become 
affected  with  a  fatal  congestion  of  blood.  Children,  on  the  other  hand, 


355 

suffer  no  inconvenience  from  a  neglect  of  this  precaution,  whether  it  is 
that,  in  them  the  vital  power  has  more  energy,  and  thus  balances  better 
the  law  of  mechanics,  by  opposing  more  powerfully  the  effects  of  gravi- 
tation, or  whether  it  is,  that  in  very  young  children,  the  parietes  of  the 
arteries  within  the  skull,  have  a  proportionate  thickness,  and  consequently 
greater  power.  The  extreme  disproportion  observable  in  adults,  in  the 
thickness  of  the  parietes,  between  the  cerebral  arteries  and  those  of  other 
parts  of  the  body,  is  but  trifling  in  children;  and  may  not  this  difference 
of  structure,  which  I  have  several  times  observed  in  the  course  of  dissec- 
tion, be  considered  as  one  of  the  principal  causes  which,  in  old  age,  bring 
on  apopolexy,  a  disease  to  which  the  child  is  not  liable? 

It  is  well  known,  that  as  the  enlargement  of  the  chest  is  produced  by 
the  depression  of  the  diaphragm,  persons  who  have  taken  a  plentiful 
meal,  dropsical  patients,  pregnant  women,  cannot  rest,  without  lying  on 
a  very  inclined  plane,  so  that  the  chest  being  considerably  raised,  and  the 
patient,  as  it  were,  seated,  the  weight  of  the  abdominal  viscera  draws 
them  towards  the  most  depending  part,  that  their  bulk  may  not  interfere 
with  the  depression  of  the  diaphragm. 

We  might  now  inquire  what  is  the  posture  in  which  the  body  rests  with 
least  fatigue  :  this  investigation,  unimportant  to  the  physician,  would  be 
of  the  highest  value  to  the  arts  which  have  for  their  object  the  imitation 
of  Nature.  In  consequence  of  ignorance  on  this  subject,  we  often  see,  in 
the  works  of  several  of  our  sculptors,  figures  in  attitudes  of  repose  so  in- 
correct and  uneasy,  that  they  could  not  maintain  them,  without  consider- 
able effort  and  fatigue. 

CLXXXVII.  Of  the  motions  of  progression.  Of  walking.  Walking, 
running,  and  leaping,  are  so  closely  connected,  that  it  is  difficult  to  dis- 
tinguish them.  There  is,  in  fact,  very  little  difference  between  walking, 
in  a  certain  manner,  or  running;  and  running  is  most  frequently  produced, 
by  the  complicated  mechanism  of  running  and  leaping.  In  the  most  na- 
tural way  of  walking,  we,  in  the  first  instance,  poise  the  body  on  one 
foot,  then,  bending  the  opposite  foot  on  the  leg,  the  latter  on  the  thigh, 
and  the  thigh  on  the  pelvis,  we  shorten  that  extremity;  we,  at  the  same 
time,  carry  it  forward,  extend  its  articulations  which  are  bent,  and  when 
firmly  applied  to  the  ground,  we  bend  the  body  forward,  and  carry  back 
the  centre  of  gravity  in  that  direction;  and  performing  the  same  motions 
with  the  limb  which  remained  behind,  we  measure  the  space  the  more 
rapidly,  cseteris  paribus,  as  the  levers  of  which  the  centre  of  the  gravity 
alternately  bears,  are  longer.  The  weight  of  the  body,  compared  to  that 
of  the  lower  extremities,  is  as  that  of  a  carriage  which  moves,  in  succes- 
sion, on  the  different  spokes  of  its  wheels. 

The  centre  of  gravity  does  not  move  along  a  straight  line,  but  between 
two  parallels,  in  which  space  it  describes  oblique  lines  from  the  one  pa- 
rallel to  the  other,  and  forms  zig  zags.  The  oblique  direction  of  the  neck 
of  the  thighbones,  accounts  for  the  lateral  oscillations  of  the  body,  when 
we  walk  ;  the  arms  which  move,  in  a  different  direction,  from  that  of  the 
lower  extremities,  serve  to  balance  us,  preserve  the  equilibrium,  and  cor- 
rect the  staggering,  which  would  be  much  greater,  if  the  neck  of  the 
thigh  bone.,  instead  of  being  oblique,  had  been  horizontal.  The  impulses 
communicated  to  the  trunk,  are  reciprocally  balanced,  and  the  latter 
moves  in  the  diagonal  of  a  parallelogram,  whose  sides  are  represented  by 
the  line  of  these  impulses.  We  constantly  deviate  from  the  straight  line, 


356 

m  walking,  and  if  the  sight  did  not  enable  us  to  see,  at  a  distance,  the  ob- 
ject towards  which  we  are  moving,  we  should  go  to  a  considerable  dis- 
tance from  it*  If  you  place  a  man,  with  his  eyes  blind-folded,  in  the  middle 
of  a  square  field,  he  will,  in  his  attempt  to  get  out,  and  thinking  that  he 
is  moving  in  a  straight  line,  make  for  one  of  the  corners.  It  is,  almost 
always,  towards  the  left  that  we  deviate*  the  right  lower  extremity,  which 
is  the  stronger,  inclining  the  body  towards  the  opposite  side*  Those 
who  are  lame  depart  much  more  from  a  straight  line,  and  deviate  to- 
wards the  side  of  the  shorter  leg.  The  motions  which  they  are  obliged 
to  use,  and  which  render  their  gait  so  remarkable,  are  occasioned  by  the 
necessity  of  incessant  and  powerful  efforts,  to  prevent  the  body  from  giv- 
ing way  to  its  own  weight^  and  to  the  greater  power  of  the  sound  extre- 
mity, which  inclines  it  towards  the  affected  side. 

The  breadth  of  the  feet,  and  a  moderate  separation  of  these  parts,  give 
a  much  firmer  support  to  the  centre  of  gravity.  Thus,  in  walking  on  a 
moving  and  insecure  surface,  we  hold  apart  our  feet,  so  as  to  include  a 
greater  base  of  sustentation.  Those  who  have  been  long  at  sea,  acquire 
such  a  habit  of  holding  their  feet  asunder,  in  the  way  they  are  obliged  to 
do  during  the  rolling  of  a  ship,  that  they  cannot  lose  the  habit,  even  when 
on  shore,  and  are  easily  recognized  by  their  gait.  A  sailor  is  unfit  for 
active  service*  till  he  has  acquired  what  is  called*  by  sea-faring  people^ 
a  seaman's  foot,  that  is,  till  he  is  capable  of  stepping  firmly  on  the  deck 
of  a  vessel  tossed  by  the  tempest. 

The  gait  of  a  woman,  from  her  having  smaller  feet,  is  less  firm  ;  but 
ought  we,  from  that  circumstance,  to  infer,  with  the  most  eloquent  wri- 
ter of  the  eighteenth  century,  that  this  diminutive  size  of  the  foot,  is  con- 
nected with  the  necessity  of  her  being  overtaken  in  flight?  The  concave 
form  of  the  soal  of  the  feet,  by  enabling  them  better  to  adapt  themselves 
to  the  unevenness  of  the  soil,  concurs  in  giving  a  firmer  footing  in  walk- 
ing, and  in  other  motions  of  progression.  There  is^  in  walking,  an  in* 
termediate  moment,  between  the  beginning  and  the  end  of  a  step,  during 
which  the  centre  of  gravity  is  in  the  air :  this  lasts  from  the  moment  whert 
the  centre  of  gravity  is  no  longer  in  the  foot  which  remains  behind,  till 
it  returns  into  the  other  foot  which  is  carried  forward. 

Walking  is  modified,  according  as  it  takes  place  on  an  horizontal  or 
an  inclined  plane  j  in  the  latter  case,  we  ascend,  or  descend,  and  the  ex- 
ertion is  much  more  fatiguing.  To  explain  the  action  of  ascending,  let 
us  suppose  a  man  at  the  bottom  of  a  flight  of  stairs,  which  he  wishes  to 
go  up  $  he  begins  by  bending  the  articulations  of  the  limb  which  he  is 
desirous  of  carrying  forward ;  he  raises  it  thus,  and  shortens  it  to  advance^ 
and  when  the  foot,  which  is  in  a  state  of  semi-extension,  rests  on  the 
ground,  he  extends  the  articulations  of  the  other  extremity,  carries  thus 
the  body  upward  in  a  vertical  direction,  and  completes  this  first  step,  by 
contracting  the  extensors  of  the  leg  that  were  first  in  action,  so  that  they 
may  bring  forward  and  restore  it  to  the  centre  of  gravity  to  which  the 
posterior  leg,  whose  foot  is  extended*,  has  given  a  vertical  motion  of  ele- 
vation. Hence,  in  ascending,  the  calves  of  the  legs  and  knees,  especially 
the  latter,  are  so  much  fatigued  ;  for,  the  effort  with  which  the  extensors 
of  the  foremost  leg,  bring  back  again  upon  it  the  centre  of  gravity,  is 
tnore  powerful  than  that  by  which  the  gemelli  and  the  soleus  impart  to 
it,  by  extending  the  hindmost  foot,  a  motion  of  vertical  elevation. 

To  relieve  the  extensors  of  the  leg,  we  bend  the  body  forward,  as  much 


357 

as  possible;  we  lean  back,  on  the  contrary,  ill  descending  a  flight  of  stairs, 
or  a  rapid  slope,  in  order  to  slacken  the  motion,  by  which  the  body, 
yielding  to  its  own  weight,  falls  on  the  leg  that  is  carried  forward, 

At  the  moment  when  the  centre  of  gravity  is  no  longer  within  the  base 
of  sustentation,  all  the  powers  unite  in  action,  that  it  may  fall,  as  little  as 
possible,  from  a  vertical .  direction.  The  glutsei  steady  the  pelvis,  and 
straighten  the  thigh,  the  lumbar  muscles  extend  the  trunk  on  the  pelvis  ; 
hence,  in  going  down  a  slope,  the  loins  get  so  much  fatigued.  We  are 
less  fatigued  in  going  down  hill,  when  the  slope  is  moderate,  than  in  going 
up  hill  |  us  the  force  of  gravitation,  or  the  weight  of  the  body*  assists  con- 
siderably the  descending  vertical  motion*  The  motion  of  walking,  when 
we  take  very  long  steps,  resembles  that  of  going  up  hill,  as  the  body  being 
lowered,  every  time  the  legs  are  much  apart,  requires  to  be  elevated,  at 
each  step,  towards  the  foremost  leg. 

At  every  step  we  take,  the  articulation  of  the  leg  with  the  foot  is  the 
principal  seat  of  an  effort,  to  which  physiologists  have  not  paid  any  at- 
tention. The  whole  weight  of  the  body  is  supported  by  the  action  of  the 
levatormusclesof  the  heel,  and  the  astralagus  supports  this  weight,  which 
varies  according  to  the  corpulence  of  the  person,  and  the  burthen  with 
which  he  is  loaded.  The  weight  of  an  adult,  of  common  stature  and  of 
moderate  size,  may  be  estimated  at  about  one  hundred  and  fifty  pounds  $ 
but  which  sometimes,  in  corpulent  people,  amounts  to  between  four  and 
five  hundred  pounds.  If,  then,  to  the  weight  of  the  body,  there  be  added 
that  of  the  burthens  which  it  may  support,  it  will  be  conceived  how  im- 
mense the  efforts  must  be,  which  are,  as  it  was  unconsciously,  carried  on, 
in  the  articulation  of  the  foot  with  the  leg.  But  how  numerous  the  re- 
sources which  nature  has  provided  to  overcome  this  great  resistance; 
how  many  the  circumstances  she  has  happily  combined  to  accomplish 
this  without  fatigue  !  In  the  first  place,  the  foot  in  this  action,  repre- 
sents a  lever  of  the  second  class,  and  this  lever,  it  is  well  known,  is  the 
most  advantageous,  the  resistance  being  always  nearer  to  the  fulcrum 
than  the  power,  and  the  arm,  by  which  the  latter  acts,  consisting  of  the 
whole  length  of  the  lever.  If  you  attend  to  the  mechanism  of  the  differ- 
ent parts  of  the  skeleton,  you  will  no  where  find  so  powerful  a  lever  ap- 
plied in  so  favourable  a  manner.  The  os  calcis,  by  carrying  the  foot  be- 
yond its  articulation  with  the  leg,  adds  likewise  to  the  length  of  the  lever 
by  which  the  power  acts.  Its  length  has  considerable  influence  on  our 
strength,  on  our  power  of  talking,  without  fatigue,  long  walks,  orengaging 
in  exertions  requiring  considerable  muscular  force  in  the  lower  extremi- 
ties. The  negroes,  who  excel  in  running,  in  dancing,  and  in  all  gymnas- 
tic exercises,  have  a  longer  and  more  projecting  heel  than  Europeans. 
They  dance  best,  whose  tendo  Achillis  is  most  detached,  that  is  to  say, 
projecting,  and  at  the  greatest  distance  from  the  axis  of  the  leg;  which 
implies,  that  its  lower  attachment  is  carried  back,  by  the  prolongation  of 
the  os  calcis. 

Those  who  have  a  short  heel,  have  a  long  and  flat  foot :  this  conforma- 
tion, which,  when  marked,  is  faulty,  is  not  only  unfavourable  to  beauty 
of  form,  but  is,  besides,  remarkably  injurious  to  the  strength  of  the  limb, 
as  well  as  to  freedom  of  motion.  Men  with  flat  feet,  are  always  bad 
walkers,  hence,  this  flattened  form,  when  very  considerable,  is  considered 
as  unfitting  a  man  for  military  service.  Lastly,  the  term  denoting  this 
physical  imperfection  (fiieds  filats,}  is  accounted  insulting  in  the  French 
language,  as  well  as  in  several  others.  But  let  us  go  on  with  our  in* 


358 

quiry  into  the  advantageous  disposition  of  the  articulation  of  the  foot 
with  the  leg,  for  facility  in  walking,  and  in  the  different  motions  of  pro- 
gression. 

We  have  seen  that  the  tendons  are  generally  inserted  at  a  very  acute 
angle,  into  the  bones  on  which  they  act;  in  the  present  instance,  however, 
the  insertion  takes  place  at  aright  angle,  the  common  tendon  of  the  mus- 
cles of  the  calf  of  the  leg  joining  the  os  calcis,  at  the  angle  most  favour- 
able to  their  freedom  of  action.  With  the  exception  of  the  muscles 
which  move  the  head  and  lower  jaw?  no  others  are  so  evidently  disposed 
with  this  purpose.  Nature  has  not  been  contented  with  forming  the  foot 
in  such  a  manner  as  to  afford  the  most  advantageous  lever,  to  which  the 
moving  powers  are  applied,  at  the  greatest  possible  distance  from  the 
fulcrum,  and  at  the  angle  most  favourable  to  their  action;  she  has  further 
increased  the  efficacy  of  this  action,  by  adding  extraordinarily  to  the 
number  of  muscular  fibres.  There  is  not,  in  the  body,  a  stronger  mus- 
cle than  the  soleus,  whose  short  and  oblique  fibres  between  the  two  wide 
aponeuroses  which  cover  its  anterior  and  posterior  surfaces,  are  more 
numerous  than  in  any  other  muscle,  as  may  be  conceived,  by  consider- 
ing the  extensive  surfaces  to  which  they  are  attached.  Besides,  the  ten- 
do  Achillis  is  kept  in  a  due  degree  of  straightness,  by  the  aponeurosis  of 
the  leg  behind  it. 

Every  thing  in  the  powers,  as  well  as  in  the  levers,  is  formed  so  as  to 
overcome  the  resistance,  without  difficulty;  that  is,  so  as  to  raise  the 
weight  of  the  body,  by  the  extension  of  the  foot,  the  end  of  which  rests 
on  the  ground  in  every  motion  of  progression. 

This  immense  power  with  which  the  muscles  of  the  calf  of  the  leg  act 
to  raise  the  heel,  and  to  support  the  whole  weight  of  the  body  resting  on 
the  astralagus,  accounts  for  the  possibility  of  transverse  fractures  of  the 
os  calcis,  and  for  the  rupture  of  the  tendo  Achillis,  notwithstanding  its 
great  thickness  ;  and  should  lead  one  not  to  allow  patients,  after  such  ac- 
cidents, to  walk  freely,  for  several  months;  the  substance  which  unites 
the  parts  being  liable  to  rupture,  as  is  known  to  have  been  the  case  in 
several  instances.  This  same  arrangement  of  parts  likewise  accounts  for 
an  accident,  which  physiologists  have  long  endeavoured  to  explain  by  a 
very  unsatisfactory  theory. 

It  not  unfrequently  happens,  that  the  mere  effort  of  walking  occasions 
a  rupture  of  some  of  the  fibres  of  the  gemelh  and  of  the  soleus.  in  conse- 
quence of  which  there  comes  on  pain,  attended  with  induration  of  the 
muscles,  and  with  a  certain  degree  of  ecchymosis,  occasioned  by  the  ex- 
travasation of  blood.  Pathologists  suppose  these  symptoms  to  depend  on 
a  rupture  of  the  plantaris  muscle:  this  rupture,  however,  is  hypothetical, 
has  never  been  proved  by  experience  to  exist,  and  its  supposed  symptoms 
are  altogether  idle  and  fallacious. 

I  could,  if  it  were  not  out  of  place,  bring  forward  several  cases  of  this 
affection  :  in  all  the  cases  which  have  come  under  my  own  observation, 
the  use  of  the  bath,  of  emollient  and  slightly  narcotic  poultices,  but  above 
all,  continued  rest,  while  the  symptoms  lasted,  have  appeared  to  me  the 
most  appropriate  remedies. 

CLXXXVIII.  Of  running.  In  running,  the  foot  that  is  hindmost 
being  raised  before  that  which  is  foremost,  being  firmly  applied  to  the 
ground,  the  centre  of  gravity  is,  for  a  moment,  suspended,  and  moves  iu 
the  air,  impelled  by  the  force  of  projection,  the  action  of  which  princi- 
pally constitutes  leaping. 


359 

The  mechanism  of  running  is  a  compound  of  that  of  walking  and 
leaping,  but  resembling  most  the  latter  5  hence  some  authors  have  defin- 
ed it  to  consist  of  a  succession  of  low  leaps.  The  steps  are  not  longer 
than  in  walking,  but  merely  succeed  each  other  with  greater  velocity. 
The  centre  of  gravity  is  transferred,  with  more  rapidity,  from  one  leg  to 
the  other,  and  falls  are  much  more  apt  to  take  place.  The  quick  repeti- 
tion of  the  same  motions,  in  running,  requires  a  very  lively  contractility 
in  the  muscles  which  move  the  extremities,  and  as  the  energy  of  this  vital 
property  is  proportioned  to  the  extent  of  respiration,  to  the  quantity  of  air 
which  the  blood  acquires  in  passing  through  the  lungs;  in  running,  we 
pant  and  breathe  frequently,  and  at  short  intervals,  without  any  particu- 
lar enlargement  of  the  chest,  at  each  act  of  respiration.  It  was  necessary 
that  the  parietes  of  this  cavity  should,  in  running,  be  remarkably  fixed  ; 
for,  it  becomes  the  point  on  which  those  muscles  are  inserted  which 
steady  the  pelvis  and  loins,  and  prevent  their  yielding  an  unsteady  basis 
to  the  lower  extremities.  The  best  runners  are  those  who  have  the 
strongest  lungs,  that  is,  who  can  give  to  the  chest  the  greatest  degree  of 
permanent  dilatation.  In  contending  for  the  prize  in  running,  you  may 
see  them  throw  back  their  head  and  shoulders,  not  only  to  obviate  the 
propensity  which  there  is  in  the  line  of  the  centre  of  gravity  to  fall  to- 
wards the  anterior  plane,  but  likewise,  that  the  cervical  column,  the  sca- 
pulae, the  clavicks,  and  the  humerus,  being  fixed,  may  furnish  a  firm  at- 
tachment to  the  auxiliary  muscles  of  respiration. 

We  should  run  with  much  less  speed,  if  we  applied  to  the  ground  the 
whole  soal  of  the  foot;  partly  from  the  time  which  would  be  taken  up  in 
thus  applying  the  foot  to  the  ground,  and  partly  by  the  friction  which 
would  necessarily  take  place.  Hence,  in  running,  we  generally  touch  the 
ground  with  the  end  of  the  foot.  We  run  with  most  speed,  when  the 
foot  is  in  a  state  of  extension,  the  leg  being  moved  rapidly  by  the  exten- 
sors of  the  knee.  This  accounts  for  the  tendency  which  there  is  to  fall 
while  we  run,  the  centre  of  gravity  obeying  the  impulses  which  follow 
each  other  in  rapid  succession,  and  never  resting  but  on  a  basis  of  very 
limited  extent.  Another  reason  why  the  slightest  unevenness  of  the 
ground  is  apt  to  occasion  falls  in  running,  is,  that  the  rapid  motion  com- 
municated to  the  body  by  the  sudden  and  perpetually  recurring  exten- 
sions of  the  posterior  extremity,  increases  at  every  step,  so  that  it  is  im- 
possible to  stop  suddenly,  and  without  having  previously  slackened  one's 
pace,  and  moderated  the  impulse  to  which  the  body  is  subjected. 

As  it  is  mostly  forward  that  falls  are  apt  to  take  place,  in  running  we 
always  throw  back  the  head,  and  make  use  of  our  arms  to  balance  the 
body,  so  that  they  may  be  in  constant  opposition  to  the  legs,  that  is,  that 
the  right  lower  extremity,  for  example,  being  carried  forward,  the  left  arm 
may  be  balanced  backward, 

Few  animals  are  better  formed  than  man  to  run  with  speed,  his  lower 
limbs  are  in  ienght  equal  to  one  half  of  the  whole  length  of  the  body,  and 
the  muscles  which  move  them  are  very  powerful ;  hence,  savages,  who 
are  in  the  constant  habit  of  running,  overtake  the  animals  which  they 
make  their  prey  ;  and,  even  in  Europe,  there  are  professed  runners  who 
equal  in  swiftness  the  fleetest  horses.  This  animal,  like  every  other  swift 
quadruped,  would  move  much  more  slowly  than  man,  on  account  of  the 
number  of  the  limbs  on  which  he  rests,  if  he  had  not  the  power  of  mov- 
ing them  in  pairs,  and  thus  reducing  his  legs  to  two,  as  in  what  is  called 
full  gallop. 


360 

CLXXXIX.  Of  leaping.  Leaping,  in  man,  is  performed,  principally 
by  the  sudden  extension  of  the  lower  limbs,  whose  articulations  were  in  r. 
previous  state  of  flexion,  The  alternate  angles  of  the  foot,  of  the  knee 
and  hip,  disappear,  and  the  extensors,,  contract  in  almost  a  convulsive 
manner.  This  straightening  is  not  limited  to  the  lower  limbs,  in  violent 
leaping:  it,  likewise,  affects  the  vrtebral  column,  which  acts  as  a  bow  in 
unbending.  Professor  Barthez,  who  has  the  merit  of  having  suggested 
this  explanation,  which  Borelli  and  Mayow  had  very  imperfectly  under- 
stood, perhaps  goes  too  far,  in  considering  as  imaginary,  a  power  of  re- 
pulsion in  the  ground.  This  re-action,  admitted  by  Hamberger  and  by 
Haller,  clearly  operates,  when  we  leap  on  an  elastic  floor;  it  enables  tum- 
blers to  rise,  without  much  effort,  on  the  rope  which  bears  them.  But 
though  ail  physiologists  do  not  admit  that,  in  leaping  there  is  are-action 
from  the  ground  ;  it  is  universally  admitted,  that  there  must  be  a  certain 
resistance,  from  the  ground  on  which  we  tread*  In  fact,  a  moving  sand, 
yielding  to  the  pressure  of  the  body,  would,  by  giving  way  to  a  consider- 
able  degree,  render  it  impossible  to  leap.  The  instantaneous  contraction 
of  the  extensor  muscles  is  so  powerful,  in  extending  the  lower  extremi- 
ties, and  in  communicating  to  the  body  a  power  of  projection,  so  as  to 
raise  it,  that  frequently,  during  this  effort,  the  tendons  of  these  muscles, 
or  even  the  bones  into  which  they  are  inserted,  break  across.  It  is  on  this 
account  that  dancers  are  very  apt  to  fracture  their  patella.  This  accident 
happens,  at  the  moment  when  their  body,  in  rising  from  the  ground,  is 
powerfully  elevated  to  a  certain  height. 

If  leaping  consists  merely  in  the  sudden  straightening  of  the  lower  ex- 
tremities,  whose  articulations  are  bent  in  alternate  directions,  it  must  be 
more  considerable,  according  as  these  are  longer,  more  bent  on  one  an- 
other,  and  as  the  muscles  which  straighten  them  contract  more  powerful- 
ly.—.Hence  animals  that  move  by  leaps,  as  the  hare,  the  squirrel,  and  the 
jerboa,  have  posterior  extremities  of  considerable  length,  in  proportion 
to  their  fore  legs.  Their  different  parts  are,  besides,  capable  of  consi- 
derable flexion.  All  these  animals,  strictly  speaking,  are  incapable  of 
walking  or  running-,  and  they  move  by  leaps  or  bounds  succeeding  each 
other  with  different  degrees  of  rapidity.  Some,  however,  as  the  rabbit 
and  the  hare)  are  capable  of  running,  when  climbing  up  a  steep  place,  as 
the  slope,  in  this  case,  lessens  the  effect  of  the  impulse  communicated  by 
the  extension  of  the  posterior  limbs;  an  impulse  which,  from  the  strength 
and  length  of  these  extremities,  throws  the  whole  weight  of  the  body  on 
the  fore  legs,  which  are  weaker  and  shorter,  with  such  a  degree  of  force 
that  the  animal  is  obliged  to  stiffen  these  and  to  keep  them  straightened, 
and  in  a  state  of  extension,  to  avoid  striking  the  ground  with  his  head, 
while  leaping  on  an  horizontal  plane.  Frogs,  but  especially  grasshoppers 
and  fleas,  between  whose  hind  extremities  and  the  rest  of  the  body,  there 
is  the  greatest  disproportion,  astonish  us  by  the  very  considerable  space 
which  they  can  clear  at  a  leap;  but  the  wonder  ceases,  when  we  consi- 
der that  powers  communicate  to  the  masses  equal  degrees  of  velocity, 
when  proportionate  to  one  another;  now,  the  space  gone  over,  depend- 
ing entirely  on  the  velocity,  since  the  body  that  leaps,  loses,  by  a  grada- 
dion  which  nothing  can  lessen,  that  which  it  had  acquired :  these  mo- 
tions must  be  nearly  alike  in  small  and  in  large  animals- 

Swammerdam  says,  that  the  height  to  which  grasshoppers  rise,  in 


361 

leaping,  is  to  the  length  of  their  body  as  200  to  1.  A  flea  leaps  still  far- 
ther and  more  swiftly*. 

The  larve,  called  the  cheese  maggot,  forms  itself  into  a  circle,  by  con- 
tracting, as  much  as  possible,  its  abdominal  muscular  fibres:  after  hav- 
ing, in  this  manner,  brought  near  to  each  other  its  head  and  tail,  it  sud- 
denly extends  and  straightens  itself,  and  sends  itself  to  a  considerable 
distance.  It  is  by  a  similar  mechanism,  that  the  salmon,  the  trout,  and 
other  fishes,  swim  against  rapid  currents  interrupted  by  water-falls.  They 
bend  their  body,  to  a  considerable  degree,  straighten  it  powerfully,  and 
thus  overcome  the  obstacle  which  opposes  their  progress.  I  believe  how- 
ever, that  in  this  particular  case,  the  leap  is  not  effected  solely  by  the 
straightening  of  the  elastic  curve,  as  is  maintained  by  some  authors,  but  that 
it  is  likewise  occasioned  by  the  resistance  against  the  water,  of  the  tail 
of  the  fish,  which  strikes  it  powerfully,  at  the  moment  of  raising  itself; 
in  the  same  manner,  as  in  the  northern  seas,  the  enormous  whale  strikes, 
with  so  sudden  and  violent  a  blow  of  her  tail  against  the  water,  as  to  re- 
ceive from  it  a  fixed  point,  and  rise  to  the  height  of  fifteen  or  twenty  feet, 
as  we  are  informed  by  navigators.  Lobsters  leap,  by  violently  extending 
their  tail,  an  elastic  and  contractile  arch,  which  they  had  previously  kept 
bent  under  their  body. 

This  theory  of  leaping  would  seem  to  be  contradicted  by  what  is  relat- 
ed by  Professor  Dumas,  of  a  man  without  thighs,  and  who,  neverthe- 
less, performed  surprising  feats  of  dexterity  and  agility.  But  in  this  in- 
stance, might  not  the  pelvis,  the  vertebral  column,  and  especially  the 
lumbar  portion  of  the  latter,  make  up,  by  a  greater  mobility,  for  the 
want  of  the  longest  of  the  three  levers  formed  by  the  lower  extremity. 

In  the  act  of  leaping  the  body,  which  has  received  the  impulse,  may 
rise  in  one  of  two  ways,  perpendicularly  to  the  horizon,  which  constitutes 
the  vertical  leap,  or  in  a  direction  more  or  less  oblique.  The  vertical 
leap  is  always  of  less  extent  than  that  which  takes  place  in  an  inclined 
direction,  and  the  latter  is  always  greater,  when  it  has  been  preceded 
by  running.  In  running  before  leaping,  we  have  already  acquired  an 
impulse  which  is  added  to  that  which  the  mechanism  of  leaping  may 
produce. 

To  convince  ourselves  of  the  reality  of  this  additional  power,  let  us 
recollect  how  difficult  it  is  to  stop  suddenly,  in  the  midst  of  a  race,  if 
we  have  not  previously  slacked  our  pace.  This  impulse  is  one  of  the 
causes  which  make  runners  fall  forward,  when  the  slightest  obstacle 
meets  their  feet;  but  whatever  may  be  the  force,  the  direction  of  leap- 
ing, and  the  powers  which  produce  it,  the  body  by  which  it  is  executed 
must  be  considered  as  a  real  projectile  that  is  impelled,  by  a  motion 
counteracted  by  the  force  of  gravitation.  Whatever  motions  we  may 
perform,  every  thing  depends  on  the  first  impulse;  as  soon  as  the  feet 
cease  to  be  in  contact  with  the  plane  which  supports  them,  it  is  no  long- 
er in  our  power  to  augment  the  force  of  the  leap  or  its  swiftness.  In 
dancing,  it  is  impossible  to  excel  in  cutting  capers,  unless  one  is  ca- 


*  Barthez  states,  in  his  work  on  mechanics,  that  the  Arabs  call  this  little  insect  the 
father  of  leaping ;  and  tht't  Roberval,  a  natural  philosopher  of  considerable  merit,  had 
written  a  work  entitled  de  saliu  pulcis.  Such  a  subject,  thought  by  the  ignorant  to  sup- 
ply matter  only  for  idle  and  fruitles  speculation,  may  furnish  results  highly  interesting, 
\vhen  treated  by  an  able  man.  In  tenui  labor. — Author's  «/V<??e, 

2Z 


pable  of  rising  to  a  certain  height ;  I  have  uniformly  observed,  that  in 
the  most  celebrated  public  dancers,  the  trunk,  and  especially  the  lower 
limbs,  are  very  muscular,  the  calf  of  the  leg,  the  buttocks,  and  the  bkck 
indicate,  by  their  bulk,  a  remarkable  degree  of  energy  in  the  extensors, 
by  whose  action,  leaping  is  chiefly  effected. 

A  dancer  who  rises  vertically,  falls  back  to  the  ground,  when  the  Force 
of  gravitation  exceeds  the  impulse  which  he  had  received  ;  his  fall  re- 
sembles that  of  a  projectile  in  vertical  motion ;  it  takes  place,  according 
to  a  descending  line  that  is  perfectly  similar,  in  direction  and  height  to 
the  ascending  line. 

The  same  thing  takes  place  in  the  oblique  leap,  except,  however,  that 
the  body,  like  a  shell  projected  by  the  explosion  of  gunpowder,  describes 
a  parabolic  curve,  ascending  as  long  as  the  impelling  power  exceeds  the 
force  of  gravitation  :  descending,  when  the  latter,  which  increases  during 
the  progress  of  the  leap,  is  equal  to  the  force  of  impulse.  This  takes 
place  when  the  body  has  described  a  curve  which  represents  the  half  of 
a  parabola  ;  from  that  moment,  the  force  of  gravitation  goes  on  increas- 
ing, and  the  body  descends  in  a  curve  corresponding  to  the  first*. 

CXC.  Of  Swimming.  Few  animals  have  more  difficulty  than  man,  in 
supporting  themselves  on  the  surface  of  a  fluid  ;  yet  the  weight  of  the  hu- 
man body  exceeds  but  little  that  of  the  same  bulk  of  water  :  sometimes 
even,  when  the  body  is  loaded  with  much  fat,  its  specific  gravity  and  that 
of  water  are  the  same.  Hence,  it  is  observed,  that  corpulent  men  swim 
with  less  effort ;  but  the  weight  is  not  equally  distributed  over  every 
point  of  the  supporting  fluid.  The  head,  whose  relative  weight  is  very 
con  sderable,  is  the  principal  difficulty  in  swimming,  and  it  requires  some 
effort  to  keep  it.  raised,  so  as  to  allow  the  air  to  enter  freely  into  the  lungs, 
through  the  mouth  and  nostrils.  The  upper  and  lower  limbs  act  alter- 
nately against  the  water  which  they  displace  by  pressing  on  it.  In  these 
various  motions,  fhere  is  a  successive  flexion,  extension,  abduction,  and 
adduction  of  the  limbs ;  most  of  the  muscles  of  the  body  are  in  motion, 
and  have  their  fixed  point  of  action  in  the  chest,  which  swimmers  keep 
expanded  by  retaining,  by  a  constriction  of  the  glottis,  a  considerable 
quantity  of  air  within  the  pulmonary  tissue.  This  continuous  dilatation  of 
the  chest  is  attended  with  this  further  advantage,  that  it  renders  the  bo- 
dy specificially  lighter.  The  force  with  which  the  swimmer  is  oblig- 
ed to  strike  the  water,  the  rapidity  with  which  the  motions  must  succeed 
each  other,  that  the  fluid  may  yield  him  a  sufficiently  fixed  point  of  ac- 
tion, accounts  for  the  fatigue  with  which  this  exertion  is  attended. 

Fishes  are  adapted  by  their  structure,  to  the  element  in  which  they 
live— the  form  of  their  body,  bounded,  every  where,  by  salient  angles, 
is  well  calculated  to  separate  the  columns  of  a  fluid.  A  bladder  filled 
with  azote,  which  is  expelled  at  pleasure,  renders  their  specific  gravity 
less  than  that  of  water,  according  to  the  quantity  of  gas  it  contains  ;  last- 
ly, their  tail  moved  by  powerful  muscles,  may  be  considered  as  an  oar  of 
great  strength,  the  motions  of  which  impel  the  fish  forward,  while  the 
fins,  like  so  many  secondary  oars,  facilitate  and  direct  his  motions. 

The  air  bladder  of  fishes  gives  to  their  back  a  sufficient  degree  of  light- 
ness to  enable  it  to  remain  upward,  else  this  part  of  the  body,  which  is 
the  heaviest,  would  draw  after  it  the  rest,  and  the  animal,  lying  on  his 

*  In  saltu  ad  horizontum,  obliquo,  motusjit  perlineamparaboUcamproxime, — Borelli.  op. 
cit  prop.  178. — Vid.  Galileo  on  the  motion  of  projectiles. 


3B3 

back,  would  be  incapable  of  performing  any  motious  of  progression  :  this 
happens  when  this  bladder  is  burst  or  punctured.  Constrictor  muscles 
expel  the  gas  which  it  contains,  and  force  it  into  the  stomach,  or  oesopha- 
gus, when  the  animal  wishes  to  sink.  This  expulsion  becomes  imprac- 
ticable, if  the  gas  undergoes  considerable  expansion,  from  the  application 
of  heat,  and  resists  the  compression  that  is  applied  to  it.  Hence,  during 
the  fry-time,  fishes  after  remaining  long  on  the  surface  of  the  water,  ex- 
posed to  the  heat  of  the  sun,  become  unable  to  sink,  and  are  easily 
caught*. 

As  the  fish  is  entirely  surrounded  by  a  medium  which  presents,  on 
every  side,  an  equal  resistance,  the  velocity  which  he  might  have  acquired, 
by  striking  the  fluid  behind,  with  his  tail,  would  be  lost,  from  the  resist- 
ance of  the  water  which  he  would  have  to  displace  forward,  if,  immedi- 
ately after  striking  with  his  tail,  he  did  not  bring  it  back  into  a  straight 
line,  so  as  to  present  to  the  fluid,  only  the  inconsiderable  breadth  of  his 
body;  the  velocity  with  which  he  moves  is,  besides,  very  inferior  to  that 
with  which  he  uses  his  tail.  This  part  being  brought  into  a  straight  line, 
the  fish  contracts  it  to  the  smallest  dimensions,  at  the  same  time  that  he 
brings  it  to  the  other  side  ;  he  then  expands  it  and  strikes  the  fluid  in  a 
contrary  direction,  in  a  line  between  the  two  oblique  impulses  which  both 
strokes  have  given  to  it.  The  fish  turns  horizontally,  and  directs  himself 
towards  the  side  he  chooses,  by  striking  more  powerfully,  or  with  great- 
er quickness,  on  one  side  than  on  the  other,  or  by  striking  only  on  one 
side. 

Fishes  without  an  air  bladder,  are  reduced  to  live  at  the  bottom  of  the 
water,  unless  they  have  a  flat  body  and  are  furnished  with  horizontal  fins, 
so  as  to  enable  them  to  strike  a  considerable  surface  of  water,  in  a  power- 
ful manner,  as  in  the  case  with  raysy  whose  wide  fins  are  not  inaptly  term- 
ed wings,  the  motion  of  these  fishes,  in  water,  precisely  resembling  that 
of  birds  in  the  air,  with  no  other  difference  but  that  of  the  different  densi- 
ty of  the  medium  in  which  they  move,  as  will  be  shown  in  treating  of  the 
motions  of  progression  peculiar  to  this  class  of  animals. 

CXCI.  Of  flying.  '  A  bird,  in  rising,  or  in  moving  in  the  air,  has  to 
use  much  more  force  and  with  much  greater  velocity,  than  a  fish  in 
swimming.  He  has  not  the  power,  like  the  latter,  of  placing  himself  in 
equilibrio  with  the  fluid  in  which  he  moves,  by  means  of  an  internal  or- 
gan that  renders  his  specific  gravity  equal  to  that  of  the  medium  he  is  in. 
This  medium,  besides,  presents  less  resistance  to  the  powers  which  strike 
it  to  obtain  a  point  of  support. 

Though  birds  are  unable  of  becoming  as  light  as  the  air,  it  is,  how- 
ever, in  their  power  to  obtain  a  specific  gravity,  not  much  exceeding  that 
of  the  atmosphere,  Nature  has  rendered  them  very  light,  by  providing 
them  with  very  capacious  lungs,  capable  of  great  dilatation,  from  the  re- 
markable-mobility of  the  parietes  of  the  chest,  and  by  extending  the  lungs 


*  The  nature  of  the  air  contained  in  the  air  bag  of  fishes  has  been  investigated  by 
PRIESTLEY  and  Fotrncnoz,  and  lately  by  M.  13toT.  According  to  the  accurate  and  ex- 
tended experiments  of  the  last  named  inquirer,  it  would  appear  to  consist  entirely  of 
oxygen  and  azote.  The  proportion  of  these  gases  varies  according  to  the  species  and 
depth  at  which  they  are  caught ;  that  of  oxygen  increasing-  with  the  depth  of  water 
from  an  almost  insensible  quantity,  until  it  amounts  to  87  parts  in  a  hundred  of  the 
whole  air.  It  would  appear  from  the  experiments  of  M.  Biot,  that  this  ail-  is  a  secretions 
from  the  sac  which  contains  it-~Auth9r's  Note. 


364 

into  the  abdomen,  by  means  of  membranous  sacs,  and  into  the  skeleton, 
by  means  of  canals  which  establish  a  communication  between  these  abdo- 
minal and  osseous  aerial  tubes  and  the  pulmonary  organ  ;  so  that  the  whole 
body,  distended  by  air  rarified  by  a  considerable  degree  of  heat,  since  it 
is  ten  degrees  above  that  of  other  warm-blooded  animals,  clothed  in  fea- 
thers almost  as  light  as  the  air  itself,  requires  but  a  moderate  degree  of 
force  to  support  itself  in  that  medium.  On  the  other  hand,  when  the 
wings  are  expanded,  they  present  to  the  fluid  a  very  extended  surface ; 
the  pectoral  muscles  which  set  them  in  motion,  are  besides  sufficient- 
ly strong  to  strike  the  air  with  a  power,  and  to  repeat  the  stroke 
with  a  rapidity  and  continuousness  of  which  no  other  animal  would 
be  capable.  We  know  how  powerful*  the  muscles  of  the  wings  are, 
even  in  the  tame  fowl,  which  make  so  very  little  use  of  them.  Last- 
ly, the  contractility  of  these  very  powerful  muscles,  is  greater  in  birds 
than  in  any  other  animal,  no  one  possesses  so  much  strength  in  so  small 
a  compass.  What  quadruped  of  the  same  weight  as  an  eagle,  could 
strike  with  his  foot  so  violent  a  blow  as  that  bird,  when  to  stun  his  prey 
or  to  defend  himself,  he  gives  repealed  blows  with  his  pinion  ?  This  mus- 
cular energy  is,  no  doubt,  connected  with  the  extensive  respiratory  or- 
gans, with  the  highly  stimulating  qualities  of  a  blood  that  is  warmer, 
more  oxidized,  more  concrescible,  in  a  word,  more  arterialized,  than  that 
of  any  other  animal. 

Let  us  now  inquire  how  birds,  endowed  with  an  organization  so  favour- 
able to  flying,  perform  that  action.  A  bird  begins  by  ascending  into  the 
air,  either  by  rising  at  once  from  the  ground,  or  by  allowing  himself  to 
fall  from  a  height.  If,  on  the  ground,  and  if  his  wings  are  too  large  to 
be  freely  spread,  he  has  a  difficulty  in  rising ;  in  that  case  he  goes  to  an 
elevated  spot  and  throws  himself  from  it,  that  he  may  have  sufficient 
room  to  extend  his  wings  and  strike,  in  the  air,  the  first  stroke  that  is  to 
raise  him.  The  wings  expand  horizontally,  the  humerus  which  forms 
their  principal  part,  standing  off  from  the  body  ;  they  then  descend  ra- 
pidly, and,  as  the  air  resists  the  sudden  effort  which  tends  to  depress  it, 
the  body  of  the  bird  is  elevated  by  a  kind  of  elastic  re-action,  correspond- 
ing to  the  leap  of  man,  and  to  the  swimming  of  fishes;  the  impulse  be- 
ing given,  the  bird  closes  his  wings,  contracts  his  dimensions,  as-  much 
as  possible,  that  the  impulse  may  be  almost  entirely  employed  in  raising 
his  body,  and  may  not  be  counteracted  by  the  resistance  of  the  air.  The 
resistance  of  the  air,  but  particularly  the  v/eight  of  the  bird,  would  soon 
overcome  the  velocity  that  has  been  obtained,  and  he  would  drop,  if,  by 
again  striking  the  air,  he  did  not  again  rise.  If  the  bird  strikes  a  second 


*  Birds  have  three  pectoral  muscles :  the  third,  or  lesser  pectoral,  is  destined  to 
draw  the  Immerus,  towards  the  body,  the  great  pectoral,  which  is  attached  to  their 
enormous  sternum,  and  alone  exceeds  in  weight  all  the  other  muscles  of  the 
bird  together;  the  middle  pectoral,  whose  tendon  turns  over  a  kind  of  pulley, 
and  is  attached  to  the  head  of  the  humerus  which  it  raises ;  by  means  of  this 
mechanism,  nature  has  placed  an  elevator  muscle  at  the  lower  part  of  the  body, 
so  as  to  increase  the  weight  of  this  part  of  the  bird,  which,  without  this  kind 
of  ballast,  might  have  been  upset  in  the  air.  By  these  and  other  peculiarities  in 
the  organization  of  flying  animals,  the  centre  of  gravity  is  always  below  the  in- 
sertion of  the  wings,  and  near  the  point  on  which  the  body  is,  during  flight,  sus- 
pended. The  positions,  also,  assumed  by  the  head  and  feet,  are  often  calculated 
to  facilitate  flight,  and  give  to  the  wings  every  assistance  in  continuing  progress- 
ive motion.—  Author's  Note. 


363 

time  with  his  wings,  before  the  impulse  communicated  by  the  tirst  stroke 
is  over,  he  rises  rapidly,  but,  on  the  contrary,  descends,  it'  this  motion  is 
delayed.  If  he  allow  himself  to  fall  only  to  the  height  whence  he  began 
to  rise,  he  muy.  by  a  continuance  of  equal  vibrations,  keep  at  the  same 
height.  A  bird,  sometimes,  ceases  altogether  to  move  his  wings,  closes 
them  against  his  sides  and  falls,  with  a  precipitate  motion,  like  any  other 
weighty  body.  The  name  of  pouncing  is  given  to  the  rapid  descent  of 
predacious  birds  on  their  prey.  Observe  a  falcon  drop  suddenly  on  a 
poultry  yard:  if  on  the  point  of  reaching  the  ground  he  perceives  dan- 
ger, he  immediately  spreads  his  wings,  and  thus  saves  himself  from 
falling ;  for,  whatever  velocity  he  may  have  acquired  in  this  rapid  motion, 
the  resistance  of  the  air  always  increases,  as  the  squares  of  the  velocity; 
he  then  rises  anew  and  takes  to  flight.  This  peculiar  act  is  called 
resource. 

The  oblique  motions  differ  from  the  .vertical  motion  which  has  just 
been  described,  in  this,  that  the  bird  rises  by  a  series  of  curves  which 
are  more  or  less  extended,  as  the  motion  is  more  horizontal  or  vertical. 
In  consequence  of  the  peculiar  strength  of  their  wings,  birds  of  prey  have 
a  very  powerful  horizontal  motion,  so  that  in  soaring,  the  curves  which 
they  describe  are  so  slight,  that  the  motion  seems  quite  horizontal. 

Swimming,  to  many  birds,  is  a  more  natural  mode  of  progression,  than 
flying;  these  birds  are  very  light,  their  body  is  covered  with  a  light 
down;  and  with  feathers  over  which  the  waters  glides  very  readily:  their 
body  is  flattened  and  rests  on  the  fluid,  by  a  broad  surface.  Their  pelvis 
is  shaped  like  the  keel  of  a  ship  ;  lastly,  their  toes,  united  by  webs,  strike 
the  water  with  a  very  broad  surface.  This  is  the  case  with  the  numerous 
tribes  of  web-footed  or  water-fowl*. 

They  who  have  conceived  it  to  be  possible  for  man  to  support  himself 
in  the  air,  by  rendering  his  body  specifically  lighter,  have  not  consider- 
ed, that  it  is  impossible  to  give  to  the  muscles  which  move  the  arms,  a 
sufficient  degree  of  strength,  to  enable  them  to  move  the  machines,  which 
are  adapted  to  them;  and  all  who  have  ventured  to  try  such  machines, 
have  suffered  for  their  rashness. 

CXCII.  Of  craiding.  All  the  motions  of  progression,  of  which  man 
and  animals  are  capable,  may  be  referred  to  the  theory  of  the  lever  of  the 
third  kind.  The  body,  in  leaping,  as  in  walking,  may  be  compared  to 
an  elastic  curve,  since  the  point  of  support,  or  fulcrum,  is  in  the  ground; 
the  force,  the  spring  of  power,  in  the  extensor  muscles,  and  the  resistance 
in  the  weight  of  the  body.  What  is  running,  but  a  succession  of  short 
leaps,  and  is  not  its  mechanism  intermediate  between  walking  and  leap- 
ing? Are  not  flying  and  swimming  real  leaps,  in  which  the  body  of  the 
animal  alternately  bends  and  unbends,  having  its  support  on  media  of 
much  less  resistance  than  the  ground,  on  which  walking,  running,  and 
leaping,  are  generally  performed  ?  The  mode  of  progression  peculiar  to 
serpents  and  soft  reptiles,  furnishes  an  additional  application  of  the  lever 
of  the  theory  of  the  third  kind,  The  snake,  which  moves  by  forming 
with  its  body  horizontal  and  vertical  undulations,  forms,  in  the  course  of 


*  The  faculty  of  diving1,  &.c.  into  a  denser  medium,  possessed  by  some  aquatic  birds, 
is  exerted  in  the  same  manner  as  that  of  flying1  in  the  air.  Swimming  on  the  surface 
of  the  water  is  performed  entirely  by  means  of  the  webbed  feet  of  this  class  of 
birds,— Authors-  Note. 


366 

Its  length,  a  series  of  curves  and  straight  lines,  in  succession,  from  the 
head  towards  thetail;  but  sometimes,  likewise,  from  the  tail  towards  the 
head,  in  the  serpents  called  amphisbcenous,  in  which  the  scales  cover- 
ing the  belly  are  equally  favourable  to  a  retrogade  motion,  as  to  a  motion 
forward. 

The  crawling  of  serpents  is  facilitated  by  the  length  of  their  body,  by 
the  smoothness  of  their  scales,  the  immense  power  of  their  muscles,  and 
the  flexibility  of  their  vertebral  column.  The  bones  which  form  this 
part  of  the  skeleton,  are  articulated  by  arthrodia,  and  loosely  jointed,  so 
that  a  very  slight  cause  destroys  their  union:  hence  a  blow,  with  a  very 
small  stick,  is  capable  of  killing  the  largest  serpent,  if  applied  on  the 
back.  The  lateral  inflections  of  this  column  are  very  considerable;  the 
degree  of  extension  is  limited  to  the  spinous  processes,  and  these  are 
sometimes,  of  considerable  size,  as  in  the  rattlesnake.  Hence,  notwith- 
standing what  has  been  stated  by  several  authors,  and  although  painters 
have  represented  serpents  moving  in  vertical  curves,  they  move, inmost 
instances,  in  horizontal  curves. 

A  serpent,  to  swim,  is  obliged  to  bend  and  unbend  his  body,  in  more 
rapid  succession;  this  swimming  consists  merely  in  crawling  faster  and 
in  moving  on  a  less  resisting  plane. 

The  motions  of  reptiles, -in  swimming,  surpass,  in  strength,  and  velo- 
city, those  of  reptiles  which  crawl  on  the  ground,  in  as  much  as  the  lat- 
ter yields  a  more  fixed  point  than  water.  If  the  serpent  is  desirous  of 
leaping,  he  suddenly,  and  at  once,  brings  to  a  straight  line  all  his  curves, 
resting,  at  the  same  time,  on  the  extremity  of  that  which  is  nearest  his 
tail :  then,  as  I  have  several  times  observed,  fce  describes  the  smallest 
possible  number  of  curves,  bends,  into  three  or  four  greater  arches 
than  usual,  but  never  into  a  single  one,  whatever  the  length  of  his  body 
may  be. 

Tortoises,  frogs,  lizards,  salamanders,  and  all  reptiles  that  have  legs, 
drag  themselves  along  on  their  belly,  being  ill  supported  by  their  weak 
limbs,  which  bear  no  proportion  to  the  bulk  of  their  body,  and  can 
scarcely  be  said  to  crawl  by  a  mechanism  similar  to  that  which  has  just 
been  explained. 

Caterpillars  and  maggots  crawl  much  in  the  same  manner  as  serpents. 
The  legs  of  the  caterpillar,  too  feeble  to  support  it,  or,  of  themselves,  to 
carry  the  body  forward,  are  used  by  these  creatures,  to  obtain  a  hold  on 
the  surface  on  which  they  move,  by  bending  in  arches,  mostly  vertical, 
the  parts  situated  between  the  legs,  that  are  in  pairs,  at  a  certain  distance 
from  one  another.  The  caterpillars  that  have  a  scaly  covering,  crawl 
better,  the  elasticity  of  their  scales  assisting  the  contractile  action  of  their 
muscular  fibres.  Earth  worms  move,  at  times,  in  undulations,  as  the 
snake,  and  at  others,  by  dragging  themselves  like  slugs.  This  last  variety 
of  crawling  is  performed  as  follows :  instead  of  forming  direct  curves, 
the  contractile  fibres  of  the  reptile,  shorten  themselves,  from  the  head, 
which  is  fixed,  towards  the  tail  which  is  moveable,  and  the  animal  per- 
forms only  slight  inflexions.  We  may  compare  the  mode  of  crawling 
peculiar  to  some  animals,  to  the  motion  by  which  a  man  lying  horizon- 
tally, on  his  belly,  moves  forward  by  drawing  his  whole  body  toward  his 
arms,  which  are  in  a  state  of  extension,  and  with  which  he  has  a  hold  of 
some  fixed  object.  The  motion  of  the  snail  is  performed  almost  entire- 
ly in  the  same  manner. 

The  snail  loaded  with  his  shell,  adheres  to  the  surface  on  which  he 


G07 

moves,  by  a  viscid  and  glutinous  fluid  which  coagulates  and  forfcis  on  his 
track,  a  shining  varnish.  This  creature  fixes  itself,  likewise,  on  the 
ground,  by  forming  a  vacuum  with  the  part  of  his  body  on  which  it 
crawls,  which  is  broad,  fringed,  and  well  adapted  to  answer  the  purpose 
of  a  cupping-glass.  It  is  by  this  double  resource  of  a  viscid  and  glu- 
tinous fluid,  and  of  a  contractile  exhauster,  that  the  snail  fixes  the  fore 
part  of  his  body,  and  then  draws  towards  this  fixed  part,  the  rest  of  his 
body  loaded  with  the  shell.  This  part  of  the  snail,  by  which  it  fastens 
itself  to  the  ground  on  which  it  crawls,  bears  some  analogy  to  the  tenta- 
cula  which  assists  the  progression  of  the  sepia  and  other  cephalopodous 
rnolusca. 

CXCIII.  Partial  motions  performed  by  the  upper  extremities.  These 
motions  will  furnish  us  additional  illustrations  of  the  elastic  curve,  or  of 
the  third  lever,  to  the  theory  of  which,  may  be  be  referred  almost  all  the 
motions  of  man  and  of  the  lower  animals.  This  idea  simplifies  and 
facilitates,  in  a  remarkable  manner,  the  study  of  animal  mechanics;  it 
may  be  considered  as  a  general  formula,  by  the  help  of  which  we  may 
obtain  a  solution  of  all  the  problems  of  this  interesting  part  of  physical 
science.  Its  application  particularly  distinguishes  what  has  just  been 
stated  on  motion,  from  what  had  been,  heretofore,  written  on  the  same 
subject. 

The  upper  extremities,  in  man,  are  not  employed  in  motions  of  pro- 
gression, at  least,  not  generally,  except  in  a  few  instances,  as  for  ex- 
ample, when  the  limbs  being  extended  and  the  hand  having  a  firm  hold 
of  a  body,  the  action  of  the  great  pectorals  draws  the  whole  body,  lying 
prone  on  a  horizontal  surface,  or  suspended. 

We  experience  a  difficulty  in  climbing,  because  our  hands  alone  enable 
•us  to  grasp  the  body,  on  which  this  mode  of  progression  is  to  be  effect- 
ed, while  the  four  extremities  of  the  quadrumana  and  the  sharp  claws  of 
cats,  those  of  climbing  birds,  render  this  action  easy  and  natural  to  all 
these  animals. 

There  exists  so  great  a  disproportion,  in  point  of  length  and  strength, 
between  our  upper  and  lower  extremities,  that  walking  on  all  fours  can 
never  be  natural  to  the  human  species;  besides,  as  Daubenton  observed, 
the  situation  of  the  foramen  magnum  of  the  occipital  bone,  in  man,  renders 
this  attitude  exceedingly  uneasy.  Its  situation,  near  the  centre  of  the  base 
of  the  skull,  and  nearly  horizontal,  prevents  the  head  from  being-  raised 
sufficiently  high  to  enable  us  to  turn  our  face  forward  and  to  see  before  us, 
and  if  we  bring  the  head  downward,  it  strikes  the  ground  wjth  its  sum- 
mit, or  with  the  forehead*.  But  our  upper  or  thoracic  limbs,  though  of 
no  use  in  conveying  us  whither  our  wants  require,  are  almost  exclusively 
destined  to  perform  motions  by  which  we  act  on  the  objects  towards 
which  we  have  brought  ourselves. 

If  we  wish  to  push,  or  to  draw  towards  us,  or  to  propel  afar  a  moveable 
body,  to  compress,  to  elevate,  or  to  lower  it,  our  upper  extremities  are 
almost  exclusively  engaged  in  this  office. 

In  pushing,  man  places  himself  between  the  obstacle  and  the  ground ; 
he  bends  his  body  between  these  two  points,  by  bringing  all  his  limbs  in- 
to a  state  of  flexion  :  he  then  extends  them;  his  whole  body  represents  a 
spring  which  is  released  and  recovers  itself,  and  the  two  extremities  of 


*  Dictionnaire  d'Histoire  Natvirelle  do  1'Encyclopedie  methodique.    Introduction, 
page  21  et  suiv. 


368 

which,  meeting  two  obstacles,  the  ground,  and  the  body  to  which  the  im- 
pulse is  to  be  communicated,  exert  their  action  on  one  of  the  two  which 
is  the  more  easily  moved.  The  force  is  equal  to  the  contraction  of  the 
extensors,  which  elongate  the  body  previously  in  a  state  of  decurtation, 
and  advance  the  moveable  obstacle  by  the  whole  difference,  in  regard  to 
length,  of  a  man,  whose  limbs  are  in  a  state  of  flexion,  and  of  the  same 
man  while  these  parts  are  in  a  state  of  extension.  It  is,  in  the  same  man- 
ner, and  by  a  similar  mechanism,  that  by  pushing  against  the  shore,  with 
an  oar,  we  force  a  boat  from  it.  The  vertebral  column  represents  an 
elastic  curve  which  straightens  itself,  between  the  feet  which  rest 
against  the  bottom  of  the  boat  and  the  end  of  the  pole  or  oar,  pushed 
against  the  shore,  or  the  bottom  of  the  water. 

If,  on  the  contrary,  we  wish  to  draw  towards  us  a  body,  we  seize  it 
with  extended  arms  5  we  then  bend  them  forcibly  :  the  spring,  which  is 
in  a  state  of  tension,  shortens  itself,  the  effort  is  wholly  performed  by 
the  flexors:  it  is  less  fixed,  and  of  less  duration  than  that  of  the  exten-. 
sors,  because  the  axis  of  the  bones  do  not  correspond  to  one  another,  in 
a  straight  line,  and  because  the  action  is  generally  partial. 

We  can  throw,  to  a  distance,  a  projectile,  the  arm  remaining  pendu- 
lous, and  performing  a  mere  oscillatory  motion,  or  by  a  whirling  motion 
of  the  arm.  This  last  action  is  much  more  powerful,  because  the  mus- 
cles which  go  from  the  trunk  to  the  upper  extremity,  concur  in  it.  In 
the  former,  the  previous  oscillations  give  to  the  arm  a  motion  which  is 
peculiar  to  it,  which  is  added  to  the  force  of  muscular  contraction,  and 
which  augments  its  effects. 

Professor  Barthez  was  av/are,  that  the  motions,  by  which  the  upper 
extremity  stiffens  itself,  and  assumes  a  state  of  extension  to  project  a 
moveable  body,  or  to  repel  a  resistance  that  is  opposed  to  it,  perfectly 
resemble  leaping,  and  are  attended,  like  that  action,  with  a  sudden  ex- 
tension of  the  joints  which  were  previously  bent.  In  motions  applied 
to  a  resistance  that  cannot  be  overcome,  the  body  is  not  repelled  with 
the  force  communicated  to  it  in  leaping,  by  the  abrupt  extension  of  the 
lower  extremities.  The  scapula  is  too  moveable  on  the  trunk,  its  arti- 
culation with  the  humerus  is  too  unsteady,  and  the  action  of  this  bone 
is  not  directed,  with  regard  to  the  shoulder,  in  a  sufficiently  favourable 
manner,  to  render  the  impulse  equally  great,  even  though  the  powers 
should  be  equal,  and  they  are  far  from  being  so.  In  every  repulsion,  and 
every  attraction,  whether  we  bring  towards  us  an  object  or  remove  it 
from  us,  by  acting  upon  it,  with  our  superior  extremities,  these  limbs 
represent  an  elastic  arch,  which  is  curved  or  straightened  by  the  action 
of  its  flexors  or  extensors,  and  these  motions,  like  the  greater  number 
of  those  which  we  have  hitherto  considered,  present  a  precise  applica- 
tion of  the  levers  of  the  third  kind. 

The  action  of  seizing  a  body  with  the  hand,  is  facilitated,  1st.  by  the 
action  of  the  radius  on  the  ulna,  which  performs  pronation  and  supina- 
tion,  motions  which  belong  exclusively  to  the  hands,  and  of  which  the 
feet  are  incapable;  2dly.  by  the  mobility  of  the  wrist,  which,  properly 
speaking,  is  capable  of  flexion  and  extension  in  two  directions ;  for,  the 
extension  of  the  head  does  not  consist  in  merely  bringing  it  into  a  pa- 
rallel line  with  the  axis  of  the  limb,  but  it  is,  besides,  capable  of  turning 
it  round  towards  the  back  part  of  the  fore-arm,  a  phenomenon  not  observ- 
able in  any  other  articulations  ;  Sdly.  by  the  obscure  motions,  on  one 
another,  of  the  bones  of  the  carpus,  by  which  the  palm  of  the  hand  be- 


369 

comes  more  concave;  4thly,  by  the  motions  of  opposition  and  circurn- 

duction  of  the  thumb  and  little  finger  ;  pthly,  by  the  great  number  of 
the  phalanges :  every  thing,  in  this  part  of  the  upper  extremity,  proves 
the  excellence  of  its  structure,  and  justifies  all  that  philosophers  and 
naturalists  have  said  of  its  advantages. 

In  applying  pressure,  for  instance,  in  pressing  on  a  seal,  nearly  the 
whole  weight  of  the  body  bears  on  one  of  the  upper  extremities,  which 
is  powerfully  extended,  the  shoulder  resting  on  the  arm,  so  that  the  gle- 
noid  cavity  of  the  scapula  may  be  perpendicular  to  the  head  of  the  hu- 
merus, 

Jt  would  be  a  superfluous  task  to  endeavour  to  describe  all  the  motions 
which  our  parts  may  execute  ;  these  partial  motions  are  explained  in 
anatomical  works,  in  treating  of  the  muscles  on  whose  action  they  depend, 
J  shall  content  myself  with  having  inquired  into  the  principal  phenomena 
of  animal  mechanism,  chiefly  with  a  reference  to  the  human  structure. 
Fuller  details,  on  animal  mechanism,  would  be  out  of  place  in  a  work  like 
this.  They  will  be  found  in  those  works  which  treat  professedly*  of  this* 
important  part  of  physiology,  the  only  one  in  which  it  is  possible  to  ob- 
tain, in  the  investigation  of  its  objects,  that  degree  of  mathematical  cer-* 
tainty,  so  much  sought  after  by  every  man  of  precision  and  of  sound 
judgment, 

CXCIV,  Partial  motions  may  yet  farther  be  studied  as  signs  ex- 
pressive of  ideas.  They  compose  what  is  called  the  language  of  action, 
and  are  supplemental  to  speech.  The  language  of  gestures,  in  its  per- 
fection, is  found  sufficient  even  to  express  the  most  subtle  ideas,  and  the 
finest  feelings,  in  the  mute  scenes,  known  under  the  name  of  pantomimes. 
The  gestures,  with  which  the  man  of  most  phlegm  accompanies  his  dis- 
course, are  a  language  superaclded  to  that  which  he  speaks:  they  contri- 
bute to  the  exposition  of  the  thought : — but  what  force,  in  the  man  of 
passion,  do  they  not  add  to  his  expression  ?  what  power  to  his  language  ? 
This  eloquence  of  gesture,  which  was  so  often  employed  to  move  and 
sway  the  assembled  multitude  in  the  public  place  of  Rome  and  Athens, 
was  habitual  to  the  orators  of  the  ancient  republics,  and  the  moment  when 
Mark  Antony  uncovers  and  shows  to  the  Roman  people  the  bloody  corse 
of  the  first  of  the  Caesars,  is  not  the  least  eloquent  passage  of  his  harangue. 

Thus,  although  the  organ  of  voice  is  that  which  offers  us  the  greatest 
abundance  of  resources  for  the  expression  of  our  ideas,  for  communica- 
tion with  our  fellow-creatures,—- though  the  hearing  be  the  sense  to  which 
we  must  address  ourselves  to  produce  in  them  distinct,  varied,  and  lasting 
impressions,— we  do  yet  address  ourselves  to  their  touch  and  their  sight, 
when  we  would  strongly  move  them,  by  an  energetic  declaration  of  our 
desires.  These  three  different  languages  are  employed  at  once,  when  we 
lead  a  man  towards  an  object,  and  at  the  same  time  point  it  out  to  him, 
and  bid  him  go  there  :  touch  and  gesture  are  then  auxiliary  to  speech, 
and  testify  in  him  who  makes  use  of  them,  a  strong  and  resolute  will. 
The  motions  of  the  eyes,  the  eye-brows,  the  eye-lids,  the  lips,  and,  gene-* 
rally,  of  all  parts  of  the  face,  those  of  the  upper  limbs,  and  of  the  trunk 


*  Consult  J,  A.  Borelli,  de  matu  animalium,  4to.  The  errors  contained  in  this  work 
depend  on  the  circumstance  of  the  author's  being  more  a  mathematician  then  an  ana- 
tomist. 

P.  J.  BartheZj  nouvelle  Jllechanigue  des  JHouvemens  dc  PHomme  et  des  Jlnimavx.—Jlu* 
Vbfe. 


370 

itself,  serve  to  express  our  passions,  as  well  as  our  ideas,  are  supplemen- 
tal to  the  language  of  convention,  and  often  betray  it,  by  saying  the  re- 
verse of  what  it  expresses.  The  study  of  gestures,  of  motions,  and  of 
attitudes,  considered  as  signs  of  ideas  and  passions,  is  the  department  of 
metaphysicians,  of  painters,  of  sculptors,  and  physiognomists*. 


CHAPTER    IX. 

OF  VOICE  AND  SPEECH, 


CXCV.  The  voice-is  an  appreciable  sound,  resulting  from  the  vibra- 
tions which  the  air,  expelled  from  the  lungs,  meets  with,  in  passing 
through  the  glottis.  From  this  sound  articulated  by  the  motions  of  the 
tongue,  the  lips,  and  other  parts  of  the  mouth,  is  produced  speech,  which 
may  be  defined  articulated  voice. 

All  animals  furnished  with  a  pulmonary  organ  have  a  voice  5  for  it  is 
sufficient,  to  the  production  of  this  sound,  that  air,  collected  in  any  re- 
ceiver, be  driven  out  in  a  body,  with  a  certain  force,  and  that  it  meet,  on 
hs  passage,  with  elastic  and  vibratory  parts.  Fish,  that  have  only  gills, 
utter  no  sound  ;  but  this  defect,  which  is  certainly  an  impediment  to  the 
extent  and  facility  of  their  relations,  is  in  part  made  up  by  the  extreme 
velocity  of  their  progressive  motion. 

The  instrument  of  voice  is  the  larynx,  a  sort  of  cartilaginous  box, 
placed  at  the  upper  part  of  the  trachea.  The  thin  and  elastic  cartilages 
which  form  its  parietes  are  united  by  membranes,  and  moved  on  one  an- 
other by  many  little  muscles,  called  laryngeal.  Of  these  five  cartilages, 
three  only  are  concerned  in  the  production  of  voice,  these  are  the  aryte- 
noid  and  the  thyroid.  The  epiglottis  is  of  no  other  use  than  to  close,  to 
what  we  swallow,  the  entrance  of  the  windpipe,  whilst  the  cricoid,  situa- 
ted at  the  lower  part  of  the  organ,  serves  it  for  a  base,  on  which  the  ary- 
tenoid  and  the  thyroid  execute  the  motions,  by  which  the  opening  of  the 
glottis  is  contracted  or  enlarged,  for  the  formation  of  acute  or  grave 
tones. 

This  slit,  from  ten  to  eleven  lines  long  in  an  adult,  and  from  two  to 
three  wide,  where  the  width  is  greatest,  is  the  most  essential  part  of  the 
larynx.  It  is  really  tke  organ  of  voice  which  is  gone  at  once,  when,  by 
opening  the  trachea  or  the  larynx  below  it,  the  air  is  prevented  from  pass- 
ing through  it.  Speech  only  is  lost,  when  the  wound  is  above  the  place 
of  the  glottis;  which  shows  that  voice  and  speech  are  two  distinct  phe- 
nomena, one  taking  place  in  the  larynx,  and  the  other  resulting  from  the 
action  of  divers  parts  of  the  mouth,  and  especially  the  lipsf. 

*  See  Condillac's  Kssay  on  the  Origin  of  Human  Knowledge  ;  Button's  Natural  His- 
tory  of  Man ;  Winkelman's  Treatise  on  Art ;  Lavater's  Essays  on  Physiognomy ;  with 
the  impo.tant  additions  by  M.  Moreau  (de  la  Sarthe)  in  the  edition  he  has  just  pub- 
lished.— Jlutnor's  Note. 

•  See  APPENDIX,  Note  H  H. 


371 

Arc  the  different  modifications  of  which  the  voice  is  susceptible,  de- 
pendent on  the  width  or  straightness  of  the  glottis,  or  on  the  tension  or 
relaxation  of  the  ligaments  forming  its  sides  ?  Must  we  believe  with  Do- 
dart,  that  the  larynx  is  a  wind  instrument,  or,  with  Ferrein,  that  it  is  a 
stringed  instrument  ?N 

It  is  very  true  that  the  voice  becomes  stronger,  fuller,  and  passes  from 
the  acute  to  the  grave,  as  the  glottis  enlarges  with  the  progress  of  age  5 
that  it  remains  always  weaker  and  sharper  in  a  woman,  whose  glottis  is 
nearly  a  third  smaller  than  a  man's ; — but  the  tension  or  relaxation  of  the 
ligaments,  which  form  the  sides  of  the  glottis,  (the  vocal  strings  of  Fer- 
rein) may  they  not  enable  these  ligaments  to  execute,  in  a  given  time,  vi- 
brations more  or  less  prolonged,  and  more  or  less  rapid,  in  such  a  man- 
ner, that  if  the  air,  expelled  from  the  lungs  by  expiration,  strike  upon 
them  in  the  state  of  tension,  produced  by  the  action  of  the  crico-aryte- 
noidei  postici,  which  carry  back  the  arytenoidal  cartilages  to  which  the 
ligaments  of  the  glottis  are  attached,  whilst  the  thyroid  cartilage,  to 
which  are  attached  the  other  extremities  of  the  same  ligaments,  is  carried 
forward  by  a  sort  of  tilting,  occasioned  by  the  muscles  connecting  it  with 
the  cricoid  cartilage,  (crico-thyroidei)*  the  voice  will  be  shrill,  that  is, 
clear  and  piercing ;  whereas  it  would  be  grave,  if  the  arytenoid  cartila- 
ges being  brought  forward  by  the  action  of  the  crico-ayrtenoidei  obliqui, 
and  the  thyro-arytenoidei  muscles,  (the  vocal  strings  being  relaxed,)  exe- 
cuted less  frequent  vibrations. 

It  has  been  objected  to  Ferrein,  that  to  perform  the  office  of  vibrating 
strings,  the  ligaments  of  the  glottis  are  neither  dry,  nor  tense,  nor  insu- 
lated, the  three-fold  condition  required  for  the  production  of  sound,  in 
the  instruments  to  which  this  anatomist  has  compared  the  larynx  $  but 
for  all  the  incompleteness  of  their  resemblance  to  strings,  the  ligaments 
of  the  glottis,  similar  to\he  vibratory  bodies,  serving  as  mouth-pieces  to 
wind-instruments,  such  as  the  reed  of  the  oboe,  the  mouth-hole  of  flutes, 
the  lips  themselves  in  the  horn,  do  not  the  less  contribute  to  the  form- 
ation and  varied  inflexions  of  the  vocal  sound.  It  is  the  more  difficult 
to  set  aside  their  influence  altogether,  inasmuch  as  their  state  of  tension 
coincides  always  with  the  contraction  of  the  glottis,  and  the  two  condi- 
tions producing  the  same  effect,  it  is  difficult  to  determine  if  it  be  due  to 
one  rather  than  the  other,  as  it  is  impossible  to  decide  whether  it  be  to 
the  enlargement  of  the  opening,  or  the  relaxation  of  the  ligaments,  that 
the  grave  tones  are  owing.  A  last  reason,  which,  I  think,  should  make 
the  larynx  be  considered  as  serving  at  once  the  purposes  of  a  wind  and  a 
stringed  instrument,  is,  that  the  ligature  or  section  of  the  recurrent  nerves, 
which  give  to  its  muscles  their  contractility,  takes  away  the  voice ;  so 
that  there  is  evidently  required  some  kind  of  action  in  the  sides  of  the 
opening. 

When  we  wish  to  speak  low,  we  contract  but  slightly,  or  not  at  all,  the 
muscles  of  the  larynx,  whose  action  is  entirely  under  the  direction  of  the 
will.  The  column  of  air  meeting,  then,  in  its  passage  along  the  glottis, 
only  relaxed  parts,  and  little  capable  of  vibration,  the  vocal  sound  is  no 
longer  produced.  The  permanent  extinction  of  the  voice,  must  depend, 
in  most  cases,  on  palsy  of  the  vocal  orlaryngeal  muscles. 


*  The  arytenoid.  muscle  is  used  in  the  formation  of  acute  sounds*  for  btiiiging  togeth. 
<?r  the  two  arytenoid  cartilages.—- Copland, 


372 

•It  appears  then,  that,  rejecting  the  opposite  and  exclusive  explanations 
of  Ferrein  and  Doclart,  we  are  to  consider  the  larynx  as  an  instrument 
combining  the  advantages,  and  exhibiting  the  double  mechanism  of  wind 
and  stringed  instruments  ;  it  is  on  this  account  that  it  surpasses  all  mu- 
sical instruments,  by  the  extent  the  perfection,  and  above  all,  by  the  in- 
exhaustible variety  of  its  effects.  There  is  no  one,  that  has  heard,  at  a 
concert,  a  solo  on  the  French  horn  by  an  able  performer,  but  has  been 
struck  with  the  resemblance  of  the  effects  of  this  instrument,  and  those  of 
the  human  voice.  It  is  because  the  vibrating  body  at  the  mouth  piece  of 
the  instrument,  is  alive  :  it  is  because  the  lips,  like  the  sides  of  the  glot- 
tis, are  moveable,  the  opening  of  the  mouth  dilates  and  contracts,  and,  at 
the  same  time,  its  edges  are  relaxed  or  stiffened  by  the  contraction  of  the 
muscles  of  the  lips. 

The  modifications  of  the  voice,  depend,  not  only  on  the  varied  sizes  of 
the  opening  of  the  glottis,  and  on  the  tension  of  its  ligaments,  but  further 
on  the.  degree  of  length  of  the  trachea.  The  singer  who  runs  down  the 
whole  scale  of  sounds,  from  highest  to  lowest,  visibly,  shortens  the  neck 
and  the  trachea,  whilst  in  ascending,  he  stretches  them  out. 

The  force  of  the  voice*  depends  on  the  volume  of  air  that  may  be  ex- 
pelled from  the  lungs  at  once,  and  on  the  degree  of  aptness,  in  the  pa- 
rietes  of  the  canals  by  which  it  is  given  out.  Birds,  whose  body  is  all 
aerial,  have  a  voice  very  strong  for  their  bulk.  Their  trachea)  furnished 
with  a  double  larynx,  is  almostf  entirely  cartilaginous.  It  is  especially  so 
in  certain  screaming  birds,  as  the  jay,  and  some  others;  whilst  it  is  nearly 
all  membranous  in  the  hedge-hog,  a  small  quadruped,  whose  cries  are 
almost  imperceptible. 

The  hissing  of  serpents,  and  the  croaking  of  frogs  are  heard  to  some 
distance,  because  these  creatures  can  send  out  a  large  quantity  of  air,  at 
once,  from  their  vesicular  lungs,  and  in  the  last,  because  the  vocal  strings 
are  completely  insulated  from  the  coats  of  the  larynx,  with  which  in  other 
animals,  they  are  continuous.  } 

The  voice  of  men  is  strong  according  to  the  capacity  of  the  chest.  It 
is  always  weaker  after  meals,  when  the  stomach  and  intestines,  distended 
with  food,  push  up  the  diaphragm  and  resist  its  descent.  The  voice, 
formed  in  the  passage  of  the  air  along  the  glottis,  acquires  much  force 
and  intensity,  becomes  much  more  sonorous,  by  the  reverberations  of  the 
sound  in  the  mouth  and  in  the  nasal  cavities.  It  is  weakened  and  disa- 
greeably impaired,  when  a  polypus  of  the  nasal  canals,  or  of  the  throat, 
or  the  destruction  of  the  roof  of  the  mouth,  prevents  the  air  from  passing 
along  the  nasal  canals,  and  their  various  sinuses.  The  voice  is  then  said 
to  be  nasal,  though,  in  truth,  it  suffers  from  want  of  the  modifications  it 
should  receive  in  the  cavities  belonging  to  the  nose. 

CXCVI.  Of  speech.  To  whisp.tr  is  to  articulate  very  weak  sounds, 
which,  in  truth,  deserve  not  the  name  of  voice,  since  they  scarcely  exceed 
the  sound,  which  always  accompanies  the  passage  of  air  in  expiration. 
Man  only  can  articulate  sound,  and  enjoys  the  gift  of  speech.  The  par- 
ticular disposition  of  the  mouth,  of  the  tongue,  and  lips  makes  all  pronun- 
ciation impossible  to  quadrupeds.  The  monkey,  in  whom  these  parts 


*  Sailors,  and  those  that  live  on  the  banks  of  great  rivers,  have  commonly  strong- 
voices  from  being  obliged  to  overpower,  with  the  voice,  the  noise  of  the  waves,  which 
bas  constrained  them  to  a  great  habitual  exertion  of  its  organs. — Authors  Note. 
•£  See  the  Memoirs  of  M.  Ctivier  on  the  double  Jarynx,  and  on  the  voice  of  the  birds.  lb. 


373 

have  the  same  conformation  as  in  man,  would  speak  like  him,  if  the  air 
as  it  leaves  the  larynx,  were  not  diffused  into  the  hyo-thyroid  cavities, 
which  are  membranous  in  some,  cartilaginous  and  even  bony  in  the 
howling  monkey,  whose  cry  is  so  hoarse  and  melancholy.  Every  time 
that  the  animal  would  utter  his  cry,  these  sacs  swell,  then  empty  them- 
selves, so  that  he  is  not  able,  at  will,  to  supply  to  the  different  parts  of 
his  mouth  the  sounds  they  might  articulate*. 

Articulated  sounds  are  represented  by  letters  which  express  their  whole 
force.  One  cannot  reflect  on  it  all,  without  seeing  what  an  advance  man 
made  towards  the  perfection  of  his  nature,  when  he  invented  these  signs 
for  the  preservation  and  transmission  of  his  thoughts.  The  vocal  sounds 
are  expressed  by  the  letters  called  vowels,  that  is  to  say,  which  the  voice 
furnishes  almost  completely  formed,  and  which  need,  for  their  articula- 
tion, nothing  more  than  the  more  or  less  opening  of  the  mouth,  by  the 
separation  of  the  jaws  and  of  the  lips.  We  pronounce,  without  effort, 
the  letters  A,  E,  I,  O,  U ;  they  are  the  first  the  child  utters;  they  appear, 
besides,  to  cost  him  less  study  than  the  consonants.  These*,  which  form 
the  most  numerous  class  of  the  letters  of  the  alphabet,  serve  only,  as 
their  name  indicates,  to  bind  together  their  vowels.  Their  pronunciation 
is  always  less  natural,  and  consequently  more  difficult.  Accordingly,  it 
is  observed,  that  the  most  harmonious  languages,  the  most  grateful  to 
the  ear,  are  those  which  use  fewest  consonants  and  most  vowels.  It  is 
in  this  point  especially,  that  the  Greek  tongue  surpasses  all,  ancient  and 
modern!  ;  that,  of  dead  languages,  Latin  holds  the  second  place ;  and. 
lastly,  that  Russian,  Italian,  and  Spanish,  are  more  agreeable  in  pronun- 
ciation, than  French,  and  still  more  than  languages  of  Teutonic  origin, 
as  English,  German,  Dutch,  Swedish,  Danish,  Sec,  Among  some  north- 
ern nations,  all  articulated  sounds  appear  to  issue  from  the  nose  or  the 
throat,  and  make  a  disagreeable  pronunciation,  no  doubt,  because  it  re- 
quires greater  effort,  and  he  who  listens  sympathizes  in  the  difficulty 
which  seems  to  be  felt  by  him  who  speaks.  Would  it  not  seem  that  the 
inhabitants  of  cold  countries  have  been  led  to  use  consonants  rather  than 
vowels,  because  the  pronunciation,  not  requiring  the  same  opening  of  the 
mouth,  does  not  give  the  same  room  to  the  continual  admission  of  cold 
air  into  the  lungs.  The  gentle  pacific  nature  of  the  inhabitants  of  Ota- 
heite,  and  of  the  other  Fortunate  Isles  of  the  South  Sea,  is  shown  in  the 
words  of  their  language,  in  which  are  abundance  of  vowels,  whilst  the 
hard  and  barbarous  speech  of  the  Esquimaux  of  the  people  of  Labrador, 
and  New  Zealand,  is  the  natural  consequence  of  the  rigour  of  their  cli- 
mate, the  barrenness  of  their  soil,  and  their  ferocious  and  warlike  habits. 

The  distinction  of  letters  into  vowels  and  consonants,  has  not  been 
thought  sufficient :  they  have  been  further  distinguished,  according  to  the 
parts  which  are  more  especially  engaged  in  the  mechanism  of  their  pro- 
nunciation. Thus  we  mark  the  labial,  oral9  nasal,  and  lingual  vowels; 
and  semi-vowek)  M,  N,  R,  L,  which  bear  different  names,  according  as 
the  tongue,  in  articulating  them,  strikes  the  roof  of  the  mouth,  the  teeth, 
or  the  lips:  lastly,  explosive  consonants,  K$  T,  P,  Q,  G,  D,  B,  P,  and  sibi- 
lant^ H,  X,  Z,  S,  J,  V,  F,  C,  which  are  more  numerous  and  more  fre- 
quently employed  in  languages  of  more  difficult  pronunciation.  If  infor- 


-  In  the  ass  ah  analogous  structure  is  obsewecL 

j Gratis  dedit  ore  rotundo 

..If UFO,  loqid. — HOHAT. 


374 

tnation  on  this  subject  could  be  of  real  utility,  I  should  explain  the  me- 
chanism of  the  pronunciation  of  every  letter  of  the  alphabet,  at  the  risk 
of  furnishing  a  new  scene  to  the  Bourgeois  Gentilhomme. 

CXCVII.  Singing,  stammering^  dumbness,  ventriloquism.  Singing  is 
nothing  more  than  voice  modulated,  that  is,  running  over,  with  varying 
rapidity,  the  different  degrees  of  the  harmonic  scale,  passing  from  the 
grave  to  the  acute,  and  from  the  acute  to  the  grave,  with  expression  too 
of  the  intermediate  tones.  Though,  in  general,  our  song  is  spoken,  speech 
is  not  necessary  to  it.  This  action  of  the  organs  of  the  voice  requires 
more  efforts  and  motions  than  speech  :  the  glottis  enlarges  or  contracts, 
the  larynx  rises  or  descends,  the  neck  stretches  out,  or  is  drawn  in  :  in- 
spiration is  accelerated,  prolonged,  or  slackened  :  expiration  is  long,  or 
short  and  abrupt.  Accordingly,  all  these  parts  are  more  fatigued  than 
by  speech,  and  it  is  impossible  for  us  to  sing  as  long  as  we  speak. 

Whatever  Rousseau  may  have  said,  in  his  Dictionary  of  Music,  singing 
may  be  regarded  as  the  most  natural  expression  of  the  emotions  of  the 
soul,  since  the  least  civilized  nations  so  use  it,  in  their  songs  of  war  and 
love,  of  joy  and  mourning ;  and,  as  every  affection  of  the  mind  modifies, 
in  some  way,  the  voice,  music,  which  is  only  imitated  song,  can,  by  the 
aid  of  sounds,  paint  love  or  rage,  sadness  or  joy,  fear  or  desire,  can  pro- 
duce the  emotions  of  these  different  states,  can  thus  sway  the  course  of 
our  ideas,  and  direct  at  pleasure,  the  operations  of  the  understanding,  and 
the  acts  of  the  will*.  Of  all  the  instruments  which  this  art  employs,  the 
vocal  organ  of  man  is,  indisputably,  the  most  perfect  that  from  which 
the  most  agreeable  combinations  and  the  most  varied  may  be  obtained. 
Who  is  there  that  knows  not  the  property  of  the  human  voice  to  lend  it- 
self to  all  accents,  and  to  imitate  all  languages!  ?  I  will  observe,  on  the 
occasion  of  song,  that  it  is  especially  consecrated  to  the  expression  of 
tender  sentiments  or  movements  of  passion,  and  that  it  is  turning  it  aside 
from  its  natural  or  primitive  destination,  to  employ  it  in  situations  where 
no  emotion  can  be  supposed.  It  is  this  that  makes  the  recitative  of  our 
operas  so  intolerably  tiresome,  and  throws  such  ludicrousness  over  dia- 
logues where  the  speakers  converse  singing,  on  the  most  indifferent  mat- 
ters. Languages  abounding  in  vowels,  are  thereby  fitted  to  song,  and 
favour  the  growth  of  musical  genius.  It  is  perhaps  their  smooth  and  so- 
norous language  that  has  given  to  the  music  of  the  Italians,  its  superi- 
ority over  that  of  other  countries^.  The  declamation  of  the  ancients 
was  much  more  removed  than  our  own,  from  the  common  tone  of  con- 
versation, approached  nearer  to  music,  and  might  be  noted  like  real 
song. 

The  pleasantness,  the  precision  of  the  voice,  the  extent  and  variety  of 


*  See  Gretry,  Essai  sur  la  Musique,  &c. 

j-  See  in  the  Aviceptologie  Francaies,  or  Art  c!e  prende  touiea  so^tes  d'  Oiseaux,  the  way 
in  which  they  are  drawn  into  snares  by  counterfeiting  their  song-. 

j  This  pre-eminence  has  been  strongly  contested,  especially  in  France,  where  to- 
wards the  middle  of  the  last  century,  a  war  arose  on  the  subject,  in  which  her  whole 
literature,  split  into  two  factions,  fought  for  the  superiority  of  Piccini  and  Gluck.  Out 
of  the  heaps  of  writings  in  verse  and  in  prose,  with  which. 'the  contest  was  carried  on,  a 
few  epigrams  will  be  remembered,  the  letter  of  Rousseau  on  French  music,  and  the 
little  work  of  D'Alembert  on  the  liberty  of  music.  Marmontel  too  has  made  these  dis- 
putes the  subject  of  an  unpublished  poem,  under  the  name  of  Voyages  de  Polymnie. — 
Note. 


375 

inflexions  of  which  it  is  capable,  depend  on  the  good  conformation  of  its 
organs,  on  the  flexibility  of  the  glottis,  the  elasticity  of  the  cartilages,  the 
particular  disposition  of  the  different  parts  of  the  mouth  and  nasal  canals, 
8cc.  It  would  be  enough  that  the  two  halves  of  the  larynx,  or  the  two 
nasal  canals,  were  unequally  developed,  to  prevent  precision  and  distinct- 
ness of  voice. 

Stammering  is  a  vice  of  pronunciation  too  well  known  to  make  it  neces- 
sary to  define  it.  A  tongue  too  bulky  and  thick,— a  remarkable  diminu- 
tion of  irritability,  as  in  drunkenness,  at  the  approach  of  apoplexy,  and 
in  certain  fevers  of  a  malignant  kind, — the  too  greatlength  of  the  frxnum 
of  the  tongue, — by  hindering  the  readiness  and  ease  of  its  motions,  be- 
come causes  of  stammering  ;  or  it  may  be  produced  by  the  want  or  bad 
arrangement  of  several  teeth.  The  same  causes,  but  especially  the  length 
of  the  fraenum  of  the  tongue,  keep  down  this  organ  against  the  lower  pa- 
rietes  of  themouth,  and  hinder  its  point  from  striking  the  anterior  part 
of  the  roof  of  the  mouth  with  the  quick  stroke,  requisite  for  the  pro- 
nunciation of  the  letter  R.  The  name  of  burr  is  given  to  this  defect  of 
speaking. 

As  for  dumbness^  it  may  be  either  accidental  or  from  birth.  When  by 
any  accident,  as  from  a  gun-shot  wound,  a  cancerous  tumour  which  has 
rendered  necessary  the  extirpation  of  part  of  the  tongue,  that  organ,  so 
far  destroyed,  is  no  longer  able  to  apply  itself  to  the  different  parts  of  the 
parietes  of  the  mouth,  and  combine  its  motions  with  those  of  the  lips, 
then  the  persons  becomes  dumb,  that  is  to  say,  deprived  of  speech.  He 
has  still  voice,  or  the  faculty  of  uttering  sounds  :  he  may  even  articulate, 
if  he  supply,  by  mechanical  means,  the  parts  of  the  tongue,  lips,  or  roof, 
the  want  of  which  hinders  his  pronunciation. 

It  is  not  so  with  the  dumb  from  birth.  Frequently,  all  parts  of  the 
mouth  are  perfect  in  their  conformation,  and  yet  the  child  cannot  attain 
to  speech.  Such  is  the  case  of  a  little  boy  of  three  years  and  a  half  old, 
who  has  been  brought  to  me,  to  divide  his  frasnum  linguae.  Sometimes, 
however,  the  tongue  adheres  to  the  lower  part  of  the  mouth,  because  the 
internal  membrane  of  that  cavity  is  reflected  over  its  upper  surface,  long 
before  it  reaches  the  middle  line  of  the  inferior.  In  other  cases,  the  edges 
of  the  tongue  adhere  to  the  gums. 

Sometimes,  also,  the  tongue  is  really  paralytic :  such  was  the  case  of 
the  son  of  Croesus,  whose  wonderful  story  is  related  by  Herodotus*. 

In  the  deaf  and  dumb  from  birth,  the  dumbness  always  arises  from  the 
deafness :  this,  at  least,  is  what  M.  Sicard  has  observed  in  the  great  num- 
ber of  pupils  committed  to  his  care,  which  has  led  him  to  say,  that  in 
them,  the  want  of  speech  should  bear  the  name,  not  of  dumbness,  but  of 
silence.  It  is  owing  entirely  to  the  absolute  ignorance  of  sounds,  and  of 
their  force  represented  by  the  letters  of  the  alphabet ;  the  organs  of  voice 
show  no  trace  of  injury  ;  they  are  well  fitted  for  fulfilling  the  purposes  to 
which  they  were  allotted  by  Nature ;  but  they  remain  inactive  because  the 
deaf  child  cannot  be  taught  to  use  them. 

It  was  necessary,  therefore^  as  the  ear  was  closed,  to  address  to  other 
senses  the  speech  he  must  endeavour  to  imitate.  His  eye  must  be  made 


This  is  the  author's  solution  of  the  story,  not  Herodotus's  statement,  who  says  ex- 
pressly the  boy  was  deaf.  But  the  conjecture  is  ingenious,  and  shows  a  possibility  in 
the  story,  which,  as  Herodotus  tells  it,  is  impossible — Tram, 


376 

to  watch  the  motions*  of  the  lips  and  the  tongue  $  his  hand  to  feel  the 
vibrations^  and  the  utterance  of  sound:  and  thence  he  must  learn  to  use 
his  organs  of  speech :  this  has  been  done.  What  Pereira  had  begun,  Si- 
card  has  brought  to  perfection;  and  such  command  of  articulate  sounds 
has  been  given  to  the  deaf  and  dumb  by  birth,  as  has  enabled  them  to 
utter  words  and  connected  discourse.  Even  something  of  inflection  of 
strong  and  weaker  tones  has  been  taught  them  by  using  the  arm  as  a  re- 
gulator, as  pedals  are  employed  to  modify  the  touches  of  the  piano-forte. 

But  instruction  to  the  deaf  and  dumb  must  be  given  them  by  another 
language.  Written  language  they  learn,  not  as  a  representative  of  speech, 
but  as  hieroglyphic  characters  for  ideas;  and  a  manual  language,  in  which 
each  letter  is  expressed  by  the  position  of  the  fingers  or  hands,  is  used  as 
a  more  convenient  and  rapid  representation  of  that  hyeroglyphic  language 
of  written  characters.  It  is  by  this  that  conversation  with  them  is  best 
carried  on  ;  and  it  is  with  an  ease  and  rapidity  which  astonishes  those, 
who,  for  the  first  time,  are  witnesses  to  the  use  of  it. 

To  conclude  this  chapter,  I  have  still  to  speak  of  a  phenomenon,  well 
worthy,  by  its  singularity,  of  the  attentiou  of  physiologists.  It  is  known 
under  the  name  of -ventriloquism,  because  the  voice  weak,  and  little  sono- 
rous, appears  to  issue  from  the  stomach.  There  was  at  the  Palais-Roy- 
al, at  the  Coffee-house  de  la  Grotte,  a  man,  who  could  carry  on  a  dia- 
logue so  naturally,  that  you  would  think  you  were  listening  to  the  conver- 
sation of  two  people,  at  some  distance  from  -one  another,  and  quite 
different  in  voice  and  tone.  I  have  observed,  that  he  was  not  inspiring 
while  he  spoke  from  his  belly,  but  that  less  air  came  from  his  mouth  and 
nostrils  than  in  his  ordinary  speaking.  Every  time  that  he  did  so,  he 
found  a  swelling  in  the  epigastric  region;  sometimes  he  felt  wind  mov- 
ing lower  down,  and  could  not  go  on  long  together  without  fatigue. 

I  had  at  first  conjectured  that,  in  this  man,  a  great  part  of  the  air  driv- 
en out  by  expiration,  did  not  issue  from  the  mouth  and  nasal  fossae,  but 
that,  being  swallowed  and  carried  down  into  the  stomach,  it  struck 
against  some  part  of  the  digestive  tube,  and  produced  a  real  echo,  but 
having  since  observed,  with  the  greatest  care,  this  curious  phenomenon 
in  Mr.  Fitz-James,  who  exhibits  it  in  the  highest  perfection,  I  have  satis- 
fied myself  that  the  name  of  ventriloquism  no  way  suits  it;  since  its 
whole  mechanism  consists  in  a  slow,  gradual,  attenuated  expiration, 
whether  for  that  purpose  the  artist  employ  the  power  of  the  will  upon 
the  muscles  of  the  parietes  of  the  chest,  or  whether  he  hold  the  epiglot- 
tis slightly  lowered,  by  means  of  the  root  of  the  tongue,  of  which  he 
scarcely  brings  the  point  beyond  the  dental  arches. 

I  find  this  long  expiration  always  preceded  by  a  strong  inspiration,  by 
means  of  which  he  introduces  into  his  lungs  a  large  quantity  of  air,  of 
which  he  afterwards  husbands  the  use.  Accordingly,  repletion  of  the 
stomach  is  a  great  hindrance  to  the  action  of  Mr.  Fitz-James,  by  pre- 
venting the  descent  of  the  diaphragm  which  the  chest  would  require,  to 
dilate  itself  for  the  full  quantity  of  air  the  lungs  should  receive. 

By  accelerating  or  retarding  expiration,  he  can  imitate  different 
voices,  make  it  seem  that  the  speakers,  in  a  dialogue,  which  he  carries  on 


*  It  is  known,  that  old  men,  grown  deaf;  fix  their  attention  very  closely  on  the  mo- 
tions  of  the  lips,  as  well  as  on  the  varying1  expressions  of  the  i'ace,  to  see  the  words  as 
well  as  thoughts  of  those  who  are  speaking. — Author's  JVbte 


377 
i 

by  himself,  stand  at  different  distances,  and  produce  illusion  the  more 
complete,  the  more  perfect  is  his  talent.  No  one  equals  Mr,  Fitz-Jame» 
in  the  art  of  deceiving,  in  this  respect,  the  most  wary  and  suspicious  ob- 
server. 

He  can  set  his  organ  to  five  or  six  different  tones,  pass  rapidly  from 
one  to  the  other,  as  he  does  when  he  represents  a  very  eager  discus- 
sion, in  a  popular  society,  imitate  the  sound  of  a  bell,  and  carry  on, 
singly,  a  conversation,  in  which  one  might  think  that  several  per- 
sons of  different  ages  and  sexes  were  taking  parts.  But  what  completes 
the  illusion}  and  especially  distinguishes  the  art  of  the  ventriloquist  from 
that  of  the  mimic,  who  can  only  counterfeit,  consists  in  the  power  of  so 
modulating  his  voice,  that  one  is  deceived  as  to  the  distance  of  the  speak- 
er,in  such  sort,  that  one  voice  comes  from  the  street,  another,  from  a 
neighbouring  apartment^  that,  from  one  that  had  clambered  up  the  roof 
of  the  house.  Sec,  It  is  easy  to  discern  the  value  of  such  a  talent  in  the 
days  of  oracles* 


SECOND   CLASS, 


FUNCTIONS 

SUBSERVIENT  TO  THE  PRESERVATION  OF  THE 
SPECIES. 


381 


CHAPTER  X. 


OF  GENERATION. 

CXCVIII.  Difference  of  the  sexes.  The  functions  treated  of  in  this 
chapter  are  not  necessary  to  the  life  of  the  individual,  but,  without  them, 
the  human  species  would  soon  perish,  for  want  of  the  power  of  reproduc- 
tion :  these  functions,  destined  to  preserve  the  species,  are  entrusted  to 
two  kinds  of  organs,  belonging  to  the  two  sexes,  of  which  they  constitute 
the  principal,  though  not  the  only  difference. 

Woman,  in  fact,  does  not  differ  from  man,  in  her  genital  organs  mere- 
ly, but,  likewise,  in  her  lower  stature,  in  the  delicacy  of  her  organization, 
in  the  predominance  of  the  lymphatic  and  cellular  systems,  which  softens 
down  the  projections  of  the  muscles,  and  gives  to  all  her  limbs  those 
rounded  and  graceful  forms,  of  which  we  see,  in  the  Venus  of  Medicis, 
the  inimitable  model.  In  woman,  sensibility  is  also  more  exquisite; 
and  with  less  strength,  her  mobility  is  greater.  The  female  skeleton 
even  is  easily  distinguished  from  that  of  the  male,  by  striking  differences. 
The  asperities  of  the  bones  are  less  prominent ;  the  clavicle  is  less  curv- 
ed, the  chest  shorter,  but  more  expanded,  the  sternum  shorter,  but  wider; 
the  pelvis  more  capacious,  the  thigh  bones  more  oblique*,  Sec.  In  a  dis- 
sertation on  physical  beauty,  read  by  Camper  to  the  Academy  of  Design, 
at  Amsterdam,  this  celebrated  physiologist  showed,  that,  in  tracing  the 
forms  of  the  male  and  female  body  within  two  elliptical  areas,  of  equal 
size  in  both,  the  female  pelvis  would  extend  beyond  the  ellipsis,  and  the 
shoulders  be  within^  while  in  man,  the  shoulders  would  reach  beyond 
their  ellipsis,  and  the  pelvis  be  contained  within  its  limits. 

The  general  characters  of  the  sexes  are  so  marked,  that  it  would  be 
possible  to  distinguish  a  male,  merely  by  seeing  a  part  of  his  body  naked, 
even  though  this  part  should  not  be  covered  with  hairs,  and  should  have 
none  of  the  principal  attributes  of  virility.  Should  this  difference  of  or- 
ganization and  character  be  abscribed  to  influence  of  the  sexual  organs 
upon  the  rest  of  the  body  ?  Does  the  uterus  impress  on  the  sex  all  its 
characteristic  modifications,  and  is  it  just  to  say  with  Vanhelmont :  Profi- 
ler solum  uterum  mulier  est^  id  quod  est ;  the  uterus  alone  makes  woman 
what  she  is.  Though  this  viscus,  very  evidently,  re-acts  on  the  whole 
system  of  the  female,  and  seems  to  draw  under  its  controul  nearly  the 
whole  of  the  actions  and  affections  of  woman,  I  am,  nevertheless,  of  opi- 
nion, that  it  is  far  from  being  the  only  cause  of  her  distinguishing  cha- 
racteristics, since  these  may  be  recognized  from  the  earliest  period  of 
life,  when  the  uterine  system  is  far  from  having  attained  its  full  activity. 
A  very  singular  fact,  recorded  by  Professor  Cailliot,  in  the  second  volume 
of  the  Memoirs  of  the  Medical  Society  of  Paris,  proves  better  than  all 


*  Compare  the  beautiful  plates  of  the  male  and  female  skeleton  by  Albinus  anc! 
Soemmering,  ' 


38% 

the  reasoning  In  the  world,  how  much  the  character  of  the  sex  is  fade* 
pendent  of  the  influence  of  the  uterus.  A  female  was  born  and  grew  up 
with  all  the  external  characteristics  of  her  sex.  At  the  age  of  twenty- 
one,  she  wished  to  yield  to  her  desires,  but  found  it  impracticable  ;  there 
was  nothing  beyond  the  vulva,  in  other  respeqts  well  formed.  A  small 
canal,  between  two  or  three  lines  in  diameter,  occupied  the  place  of  the 
vagina,  and  terminated  in  a  cul  de  sac,  and  was  about  an  inch  in  depth. 
The  most  accurate  examinations,  by  introducing  a  sound  into  the  blad- 
der, and  the  finger  up  the  rectum,  discovered  nothing  like  the  uterus. 
With  the  finger  in  the  rectum,  the  convexity  of  the  sound  in  the  bladder, 
could  be  distinctly  felt,  so  that  it  was  evident,  that,  between  the  lower 
part  of  the  bladder  and  the  anterior  part  of  the  rectum,  there  lay  no  o*- 
gan  corresponding  to  the  uterus.  The  young  woman,  had  never  been 
subject  to  the  periodical  evacuation  which  accompanies  or  precedes  the 
time  of  puberty.  No  haemorrhage  supplied  the  place  of  this  excretion. 
She  experienced  none  of  the  indispositions  that  are  occasioned  by  the 
absence  of  menstruation ;  she  enjoyed,  on  the  contrary,  the  most  perfect 
health;  she  was  deficient  in  none  of  the  other  characteristics  of  her  sex, 
only  that  her  breasts  were  small.  At  the  age  of  twenty-six  or  twenty- 
seven,  she  became  subject  to  a  pretty  frequent  evacuation  of  bloody  urine. 
May  not  this  affection,  which  recurred  at  irregular  periods,  be  consider- 
ed as  a  means  by  which  nature  supplied  the  deficiency  of  the  menstrual 
evacuation  ?  The  bladder,  in  that  case,  would  fulfil  the  office  of  the  Ute<- 
rus,  and  its  capillary  vessels  must  have  been  considerably  evolved. 

The  reproduction  of  the  species  is,  in  woman,  the  most  important  ob« 
ject  of  life  5  it  is  almost  the  only  destination  to  which  Nature  has  called 
her,  and  the  only  duty  she  has  to  fulfil  in  human  society.  Wherever  the 
earth  is  fruitful,  and  furnishes  man  with  abundant  means  of  providing 
for  his  wants,  he  dispenses  with  the  services  of  woman,  in  obtaining  from 
it  means  of  subsistence,  he  releases  her  from  the  burthen  of  social  obliga- 
lions.  The  Asiatic  expects  from  the  women  he  maintains  in  his  seraglio, 
in  a  state  of  inactivity,  nothing  but  pleasures  and  children  to  perpetuate 
his  race.  The  women  of  Otaheite  have  no  employment  but  pleasure  and 
the  duties  of  mothers.  Among  some  of  the  savage  tribes  of  America, 
man,  abusing  the  right  of  power,  tyrannizes,  it  is  true,  over  woman,  and 
reserving  to  himself  all  the  advantages  of  social  life,  makes  her  bear  all 
its  weight;  but  this  exception  does  not  invalidate  the  general  law  de- 
duced from  observation  of  all  nations.  Whatever  withdraws  woman 
from  this  primitive  destination ;  whatever  diverts  her  from  this  end  is 
to  her  injury ;  it  is,  the  scope  of  all  her  actions  and  habits,  every  thing, 
in  her  physical  organization?  has  evident  reference  to  it.  Of  all  the  pas- 
sions, in  woman,  love  has  the  greatest  sway;  it  has  even  been  said 
to  be  her  only  passion.  It  is  true*  that  all  the  others  are  modified  by  it, 
and  receive  from  it  a  peculiar  cast,  which  distinguishes  them  from  those 
of  man*. 

We  will  enter  no  further  into  the  examination  of  the  general  differences 
which  characterize  the  two  sexes  ;  no  one  has  entered  more  deeply  into 


*'  Fontenelle  used  to  say  of  the  devotion  of  some  women  :  One  may  see  that  love  has 
been  here.  It  has  been  said  in  speaking  of  St.  Theresa :  To  love  God  is  still  to  love. 
Thomas  maintains  that,  ivith  women,  a  man  is  more  than  a  nation.  Love  is  but  an  episode 
in  the  life  of  man  ;  it  is  the  whole  history  of  the  life  of -woman.  (Madame  DE  S 


this  subject,  or  has  treated  it  in  a  more  interesting  manner,  than  Mi 
Roussel,  in  an  excellent  work  entitled,  Syateme  physique  ct  morale  de  la 
femme. 

XCIX.  Htrmaphrodism.  Hermaphrodism9  or  the  union  of  the  two 
sexes  in  the  same  individual,  is  impossible  in  man,  and  in  the  numerous 
class  of  red-blooded  animals*  There  is,  on  record,  no  well  authenticated 
case  of  such  a  combination^  and  all  the  hermaphrodites,  that  have  been 
hitherto  met  with,  were  beings  imperfectly  formed  ;  in  whom  imperfect 
male  organs,  or  female  organs  unnaturally  enlarged,  rendered  the  sex  du- 
bious. None  was  ever  found  that  had  the  power,  by  itself,  of  begetting 
a  similar  being  to  itself:  the  greater  number  were  incapable  of  reproduc- 
tion :  the  imperfection,  or  the  faulty  conformation  of  their  organs,  con- 
demned them  to  barrenness.  Such  was  the  case  with  the  hermaphrodite 
mentioned  by  Petit  Namur,  in  the  Memoirs  of  the  Academy  of  Sciences; 
•with  that  one  whose  case  is  related  by  Maret,  in  the  Memoirs  of  the  Aca- 
demy of  Dijon,  and  with  all  those  to  be  found  in  the  records  of  the  Me- 
dical Society,  which  contain  the  greatest  number  of  facts  of  this  kind. 

But  though,  in  man^  and  in  all  beings  that  most  resemble  him,  in  their 
Organization,  complete  hermaphrodism  has  never  been  met  with,  it  is  a 
frequent  occurrence  among  the  white-blooded  animals,  and  especially 
among  the  plants  that  occupy  the  lowest  part  of  the  scale  of  organized 
beings.  The  same  is  observed  in  polypi,  in  several  kinds  of  worms,  in 
oysters,  and  snails.  The  latter  present  a  singular  variety  of  hemaphro- 
dism,  in  this,  that  the  male  and  female  organs  being  combined  in  the 
same  individual,  it  is  still,  singly,  not  capable  of  generation,  but  is  obliged 
to  copulate  with  another  being  likewise  an  hermaphrodite,  so  as  to  re- 
ceive, from  friction,  and  other  means  of  irritation,  the  excitement  of  the 
act  of  reproduction, 

In  the  immense  tribe  of  monoecious  plants,  the  male  and  female  organs 
are  combined  on  one  stalk,  and  even  sometimes  within  the  same  flower* 
A  number  of  stamina  surround  one  or  more  pistils,  and  shed  on  the  stig- 
ma their  fertilizing  dust  or  pollen,  which  is  conveyed,  along  the  canal  of 
the  style,  into  the  ovary,  there  to  impregnate  the  seeds  by  means  of  which 
the  species  are  perpetuated,  The  same  vegetable  species  containing,  some- 
times, male  and  female  individuals,  the  sexes  may  be  at  considerable  dis- 
tances from  one  another;  the  seminal  dust  is$  in  that  case,  conveyed  by 
the  air  from  the  male  to  the  female.  This  is  the  case  with  the  palm  trees 
on  which  Gleditsch  made  his  tirst  observations  on  the  generation  of  plants; 
hemp,  spinage,  mercurialis,  &c, 

CC.  It  is  a  distinction  of  the  human  species  that*  in  them,  the  func- 
tions  of  generation  are  not  under  the  influence  of  the  seasons.  The  lower 
animals,  on  the  contrary,  draw  together,  and  pair  stated  periods  of  the 
year,  and  seem  afterwards  to  forget  the  enjoyments  of  love,  that  they  may 
attend  to  their  other  necessities.  Thus,  wolves  and  foxes  copulate  in  the 
middle  of  winter;  deer,  in  autumn,  most  birds  in  spring.  Man  alone 
seeks  his  partner  at  all  seasons  of  the  yearj  and  impregnates  her  under  all 
latitudes  and  in  all  temperatures.  This  privilege  is  not  so  much  the 
consequence  of  his  peculiar  constitution,  as  a  result  which  he  derives 
from  his  industry)  protected  by  the  shelters  which  he  constructs  against 
the  inclemency  of  the  seasons,  and  the  variations  of  the  atmosphere ; 
always  capable  of  gratifying  his  physical  wants  by  help  of  the  stores 
which  his  foresight  has  led  him  to  collect,  he  can  at  all  times  indulge  in 
the  enjoyments  of  love.  The  domestic  animals  which  we  have,  in  great; 


884 

measure,  removed  from  the  influence  of  external  causes^  bring  forth  al- 
most indiscriminately,  at  all  seasons  of  the  year.  To  prove  still  farther^ 
that  is  from  counteracting,  by  the  resources  of  his  industry*  the  influence 
of  nature^  that  man  has  succeeded  in  resisting;  the  influence  of  the  sea- 
sons, in  the  reproduction  of  his  species,  1  may  observe,  that  this  effect 
of  temperature  is  more  absolute,  the  farther  the  species  is  from  man; 
hence  the  spawn  of  fishes  and  frogs  is  productive  sooner  or  later,  accor-* 
ding  to  the  earliness  or  lateness  of  the  season,  and  thus  a  great  number 
of  insects  depend  on  the  heat  of  the  weather  for  their  powers  of  repro- 
duction, and  for  their  existence. 

CCI.  Of  the  organs  of  generation  in  man.  Aristotle,  Galen,  and  their 
verbose  commentators,  have  expressed  the  analogy  which  subsists  be- 
tween the  organs  of  generation,  in  the  two  sexes,  by  saying  that  f.hey 
differ  only  in  their  position,  being  external  in  man,  and  internal  in  woman. 
There  is,  in  fact,  a  considerable  resemblance  between  the  ovaria  and  the 
testicles,  the  fallopian  tubes  and  the  vasa  deferentia,  the  uterus  and  the 
vesiculoe  seminalis,  the  vagina,  the  external  organs  of  generation  in  wo- 
men, and  the  male  penis.  The  former  secrete  the  seminal  fluid,  and  fur- 
nish in  man  or  in  women,  a  matter  essential  to  generation  (ovaria  and 
testicles.)  The  fallopian  tubes,  like  the  vasa  deferentia,  convey  this  fluid 
into  recepticies  where  it  has  to  remain  for  some  time  (uterus  and  vesiculse 
seminales.)  These  contractile  cavities,  which  serve  as  reservoirs  to  the 
semen,  or  its  product,  part  with  these  substances,  when  they  have  re- 
mained within  them  a  sufficient  length  of  time ;  lastly,  the  vagina  and 
penis  serve  to  expel  them.  However  striking  such  analogies  may  be,  we 
are  not  justified  in  inferring  a  perfect  resemblance  between  the  organs  of 
generation  in  the  two  sexes*  Each  of  them  fulfils,  in  ,the  act  of  repro- 
duction, functions  perfectly  distinct,  though  of  reciprocal  necessity. 

The  prolific  fluid  is  secreted  by  the  testicles  :  these  organs  are  two  in 
number,  covered  by  several  coats,  one  of -which,  covered  by  the  skin,  and 
known  under  the  name  of  scrotum)  resembles  a  bag  containing  both  these 
organs  :  it  contracts  on  the  application  of  cold,  is  relaxed  by  heat,  and 
possesses  a  degree  of  contractility  more  evident  than  the  other  parts  of 
the  cutaneous  tissue.  The  dartos  forms  a  second  cellular  envelope  com- 
mon to  each  testicle*  The  tunica  vaginalis,  a  serous  membrane,  affords 
an  immediate  covering  to  them,  and  reflecting  itself  over  the  surface,  is 
disposed  with  regard  to  them,  as  the  peritoneum  with  regard  to  the  abdo- 
minal viscera,  that  is,  it  does  not  contain  them  within  its  cavity.  Lastly, 
the  testicles  are  covered  by  a  fibrous,  white*  thick,  and  very  consistent 
membrane  :  it  is  termed  tunica  albuginea,  from  the  inner  surface  of  which 
there  arise  a  considerable  number  of  membranous  lamina,  which,  crossing 
one  another,  within  its  cavity,  form  cells  containing  a  yellowish  vascular 
substance.  This  substance  contained  within  the  tunica  albuginea,  has  so 
little  consistence,  that  it  would  very  soon  be  dissolved,  if  the  testicle  were 
stripped  of  its  outer  covering.  It  is  formed  by  the  seminiferous  tubes, 
which  are  small  capillary  vessels  extremely  tortuous  and  coiled  on  them- 
selves, arising,  probably,  from  the  extremities  of  the  spermatic  arteries, 
all  directed  towards  the  upper  part  of  the  oval  formed  by  the  testicles, 
joining  in  this  place,  and  forming  about  ten  or  twelve  tubes,  which  unite 
into  a  cord  situated  within  the  tunica  albuginea*  called  the  corjius  High- 
morianum.  The  ten  or  twelve  ducts  which  unite  into  a  fasciculus,  and 
form  this  cord,  pass  through  the  membrane  within  which  they  are  con- 
tained, unite  into  a  single  canal  which  is  convoluted,  and  form?  a  sub- 


stance  called  the  epididymis.  This  canal,  formed  by  the  union  of  the 
ducts  of  the  corpus  Highmorianum,  at  first  convoluted  on  itself,  becomes 
less  and  less  tortuous,  as  it  approaches  the  lower  extremity  of  the  testi- 
cle :  there  it  bends  back  and  ascends  under  the  name  of  vas  deferens, 
along  the  spermatic  cord,  as  far  as  the  inguinal  ring,  by  which  it  enters 
the  abdominal  cavity.  The  vasa  deferentia,  though  of  the  size  of  a  quill, 
have,  nevertheless,  a  very  small  cavity,  and  it  is  not  easy  to  say  why  a 
capillary  tube  should  have  such  thick  pareties,  and  nearly  as  hard  as 
cartilage. 

The  semen,  secreted  by  the  testicles,  is  formed  from  the  blood  conveyed 
to  them  by  the  spermatic  arteries,  long,  slender,  and  very  tortuous  ves- 
sels, arising  from  the  aorta,  at  a  very  acute  angle.  This  fluid  is  filtered 
through  the  seminiferous  tubes,  passes  into  those  of  the  corpus  High- 
morianum, and  thence  into  the  vasa  deferentia,  which,  after  they  have  en- 
tered the  abdomen,  terminate  into  the  vesicuse  seminales,  and  deposit  into 
them  the  spermatic  fluid.  The  delicacy  of  the  organization  of  the  testicle, 
the  delicacy  of  the  vessels  along  which  the  semen  is  conveyed,  account 
for  its  tendency  to  congestion,  and  for  the  difficulty  with  which  a  resolu- 
tion of  this  affection  is  obtained. 

The  spermatic  fluid  passes,  from  the  vasa  deferentia,  into  the  vesicular 
seminales,  notwithstanding  the  retrograde  direction  of  their  course.  The 
cavities  serving  as  receptacles  to  the  semen,  resemble,  in  this  respect,  the 
gall  bladder.  Notwithstanding  the  unfavourable  direction  in  which  the 
ducts  of  the  liver  and  of  the  testicles  join  in  their  respective  receptacles, 
they  nevertheless  convey  the  fluids  into  the  latter ;  the  bile,  because  the 
ductus  choledocus  is  pressed  by  the  coats  of  the  duodenum,  contracted 
on  itself  when  empty  5  the  semen,  because  the  duct  along  which  it  is  con- 
veyed, penetrating  through  the  prostate  gland,  and  opening  into  the  ure- 
thra, by  a  very  narrow  orifice,  this  fluid  flows  back  more  readily  into  the 
vesiculae  seminales,  than  from  the  vas  deferens  into  the  ejaculatory  duct. 

The  vesiculae  seminales  form  two  membranous  receptacles  of  different 
capacity,  in  different  individuals,  larger  in  young  people  and  adults,  than 
in  children  and  old  people.  Their  cavity  is  divided  into  a  number  of 
cells  ;  they  are  lined  with  a  mucous  membrane,  which  secretes,  in  con- 
siderable quantity,  a  viscid  humour  that  mingles  with  the  semen,  in- 
creases its  quantity  and  serves  as  a  vehicle  to  it.  The  situation  of  the 
vesiculae  seminales,  between  the  rectum,  the  levatores  ani,  and  the  pos- 
terior part  of  the  bladder,  promotes  the  excretion  of  their  contents, 
(which  is  chiefly  brought  about  by  the  contraction  of  their  parietes)  by  the 
compression  of  the  levatores  ani,  which  are  in  a  state  of  convulsion  at  the 
moment  of  emission.  Animals  that  are  not  provided  with  these  seminal 
receptacles,  remain  a  considerable  time  in  a  state  of  copulation,  the  pro- 
lific fluid  necesfary  to  impregnation  having  to  be  secreted  during  the 
time  that  the  copulation  lasts,  and  flowing  in  drops. 

The  ducts  formed  by  the  union  of  the  vesiculae  seminales  with  the  vasa 
deferentia,  pass  through  the  prostate  gland,  and  open,  by  separate  ori- 
fices, into  the  urethra,  at  the  bottom  of  a  lacuna,  near  the  verumoritanum. 
The  glandular  body  in  which  they  are  inclosed,  and  which  contains  both 
the  neck  of  the  bladder  and  the  beginning  of  the  urethra,  does  not  exist 
n  women.  The  mucous  and  whitish  fluid,  secreted  by  the  prostate,  is 
conveyed  by  ten  or  twelve  orifices  into  the  urethra.  This  prostatic  fluid 
mingles  with  the  semen,  adds  to  its  quantity,  is  perhaps  emitted  first,  in 
order  to  lubricate  the  internal  surface  of  the  canal,  and  prepare  it  for  the 

3  C 


386 

passage  of  the  seminal  fluid,  by  rendering  the  internal  surface  of  the 
urethra  more  slippery.  The  use  of  the  urethra  is,  not  only  to  convey 
the  semen  out  of  the  body,  but  likewise  to  serve  in  the  excretion  of  the 
urine,  and  to  form  a  part  of  the  penis.  The  latter  destined  to  convey 
the  prolific  fluid  into  the  female  organs  of  generation,  must  be  in  a  state 
of  erection  to  perform  this  function  completely.  Erection  being  a  phe- 
nomenon of  structure,  that  of  the  penis  will  be  considered,  after  the  de- 
scription of  the  female  organs  of  generation*. 

CCII.  Of  the  female  organs  of  generation.  I  shall  not  adopt  the  ana- 
tomical arrangement  generally  followed  in  this  description,  but  classing 
in  three  divisions,  the  different  parts  which,  in  women^re  subservient  to 
the  genital  function,  I  shall  speak  first  of  the  ovaria  and  fallopian  tubes, 
then  of  the  uterus,  and  in  the  last  place  of  the  vagina  and  external  parts. 

The  ovaria,  situated  in  the  female  pelvis,  connected  to  the  uterus  by  a 
ligament,  receive  the  vessels  and  nerves  which,  in  women,  are  sent  to  the 
testicles ;  they  resemble  in  form  the  latter,  but  are  somewhat  smaller. 
Do  the  ovaria  secrete  a  fluid,  which,  by  mixing  with  the  male  semen, 
produces  the  new  being,  or  is  there  detached  from  them,  at  the  moment 
of  conception,  an  ovum  which  the  semen  vivifies?  Whatever  opinion 
is  adopted,  one  is  compelled  to  admit,  that  the  ovaria  prepare  a  substance 
essential  to  generation,  since  females,  in  whom  these  parts  have  been  ex- 
tirpated, are  rendered  barren. 

It  is  likewise,  unquestionably  along  these  membranous  tubes,  called 
fallopian,  that  this  substance,  whatever  it  may  be,  furnished  by  the  ovaria, 
passes  into  the  uterus,  into  which  one  of  their  extremities  opens  :  while 
the  other  extremity,  broad  and  fringed,  lies  loose  in  the  cavity  of  the  pel- 
vis, supported  by  a  small  duplicature  of  the  peritoneum,  but  undergoes 
a  state  of  erection,  and  applies  itself  to  the  ovarium,  during  the  act  of 
coition,  and  forms  a  continuous  canal  between  that  organ  and  the  cavity 
of  the  uterus.  The  external  orifice  of  the  fallopian  tube,  called  corpus 
fimbriatum,  has  been  found  grasping  thus  the  ovarium,  in  females  opened 
immediately  after  coition.  It  may  happen,  from  a  malformation  of  the 
parts,  that  the  fallopian  tube  may  not  be  able  to  apply  itself  to  the  ova- 
rium. I  dissected  at  the  Hospital  de  la  Charite,  the  body  of  a  woman 
who  had  been  barren ;  and  found  the  corpora  fimbriata,  or  the  expanded 
termination  of  the  fallopian  tubes,  adhering  to  the  lateral  parieties  of  the 
pelvis,  so  that  it  was  impossible  they  should  perform  the  motions  re- 
quired for  impregnation. 

The  uterus,  lying  in  the  pelvis,  between  the  rectum  and  the  bladder,  is 
a  hollow  viscus,  in  which  the  foetus  grows  till  the  period  of  birth.  Its 
internal  part  has  been  found  separated  into  two  cavities,  opening,  in  some 
cases,  in  the  same  vagina,  and  at  others,  terminating  in  a  vagina  that 
•was  double,  only  in  the  immediate  vicinity  of  the  uterus.  Valisnieri 
mentions  the  case  of  a  woman  who  had  a  double  uterus,  the  one  opening 
in  the  vagina,  and  the  other  communicating  with  the  rectum.  Though 
the  muscularity  of  the  pareties  of  the  uterus  becomes  manifest,  in  pro- 
portion as  this  organ  enlarges,  during  the  progress  of  pregnancy,  this 
hollow  muscle  may  be  said  to  differ  from  other  muscular  organs,  by  the 
arrangement  of  its  fibres,  which  it  is  difficult  to  discover  while  its  cavity 
Is  empty,  and  which  it  is  even  impossible  completely  to  unravel,  while  it 
contains  the  foetus  ;  its  most  remarkable  distinguishing  character,  is  its 


See  APPENDIX,  Note  1 1. 


387 

singular  property  of  dilating  and  stretching  itself,  and,  at  the  same  time, 
of  gaining  in  thickness  instead  of  becoming  thinner. 

The  vagina  is  remarkable,  only  by  the  soft,  wrinkled,  and  easily  dila- 
ted structure  of  its  parietes.  The  upper  extremity  of  this  oblique  canal, 
which  is  directed  upward  and  backward,  embraces  the  cervix  of  the  ute- 
rus, while  its  lower  orifice  is  surrounded  by  a  spongy  body,  whose  cells 
fill  with  blood  and  expel  it,  like  the  corpora  cavernosa  of  the  penis  and 
clitoris.  It  is  called  plexus  retiforme  ;  its  turgesccuce,  during  erection, 
contracts  the  orifice  of  the  vagina  ;  the  contraction  of  the  constrictor 
muscles,  which  answers  the  purpose  of  the  accelerator  urinae  in  man,  and 
which  lies  over  this  plexus  retiforme,  surrounds,  like  it,  the  entrance  of 
the  vagina,  and  may,  in  the  same  manner,  contract  the  orifice  of  this  canal. 

Besides,  this  external  orifice  is  furnished,  in  women  who  have  had  no 
connexion  with  men,  with  a  membranous  fold,  varying  in  breadth,  gene- 
rally semicircular,  and  called  hymen.  Its  existence  is  considered  by 
many,  as  the  most  certain  sign  of  virginity.  But  all  the  marks  by  which 
it  has  been  attempted  to  obtain  a  certainty  of  the  presence  of  virginity 
are  very  equivocal*.  The  relaxed  state  of  the  parts,  from  a  great  quan- 
tity of  mucus,  in  a  woman  subject  to  the  fluor  albus;  or  from  the  blood 
of  the  menstrual  discharge,  may  make  the  hymen  yield  and  not  rupture, 
so  that  a  woman  might  seem  a  virgin  without  being  such  ;  while  another 
•woman  who  has  not  lost  her  virginity,  might,  from  illness,  have  her  hy- 
men destroyed.  There  are,  in  the  last  place,  persons  in  whom  the  hymen 
is  so  indistinct,  that  several  anatomists  have  doubted  its  existence!. 

The  other  external  parts  of  generation,  which  are  easily  discovered, 
without  the  aid  of  dissection,  cannot  be  considered  as  merely  ornamen- 
tal ;  all  are,  as  will  be  shown  presently,  of  real  utility.  The  folds  of  skin 
which  form  the  labia  and  the  nymphae,  yield  during  the  delivery  of  the 
fo3tus.  These  duplicatures  not  only  unfold  themselves,  but  likewise  un- 
dergo a  degree  of  extension,  their  tissue  being  moister,  softer,  and  more 
extensible  than  that  of  the  skin.  The  mons  veneris,  the  hairs  which 
cover  it,  the  clitoris,  which  resembles  an  imperfect  penis,  seem  merely 
organs  of  voluptuousness;  but  is  not  pleasure  itself  an  element  in  the 
act  by  which  the  human  species  is  reproduced}:  ? 

CCIII.  Of  conception.  When  a  chemical,  mechanical,  or  mental  irri- 
tation excites  the  action  of  the  genital  organs,  the  penis  elongates  itself, 
becomes  turgid  and  stiff,  from  the  accumulation  of  blood  within  the  cells 
of  the  corpus  cavernosum,  and  within  those  of  the  corpus  spongiosumof 
the  urethra§.  The  turgescence  of  these  two  parts  of  the  penis  should  be 
simultaneous,  to  render  the  erection  complete.  It  has  been  thought  that 
this  phenomenon  might  be  accounted  for,  by  the  compression  of  the 
pudic  veins,  which  are  situated  between  the  symphysis  pubis  and  the 
root  of  the  penis,  which,  as  long  as  the  erection  lasts,  is  compressed 
against  the  bone  by  the  erector  muscles.  But  far  from  elevating  the  penis, 
the  muscles  of  the  perineum,  especially  the  ischio  cavernous  (erectores 


*  Attamen  prima  venusdebet^esse  cruenta." — Hatter. 

•j-  It  nevertheless  always  exists,  but  its  size  is  very  various.  In  some  females  it  coi* 
pletely  closes  the  vagina,  and,  in  this  case,  it  causes  retention  of  the  menses.  In  other 
cases,  the  occlusion  not  being1  complete,  foccundation  may  take  place  by  menns  of  a 
very  small  opening-,  and  without  the  introduction  of  the  penis — Copland. 

*  See  APPENDIX,  Note  1 1. 

§  «•  Penis  adest,  ita  consmctus,  ut  sthnulo  corporeo  sive  mentali  irritatus,  turgeat  et 
obrigescat,  seque  erigat,  postea  detumescat,  et  collabatur."—  Crevt. 


tend  to  depress  It.  The  blood  -which  distends  the  corpora 
flosa  of  the  penis,  and  the  corpus  spongiosum  of  the  urethra  and  glans, 
which  is  itself  the  expanded  extremity  of  the  urethra,  does  not  stagnate  in 
their  cells,  only  there  is  a  greater  quantity  of  blood  in  them  than  usual;  the 
irritation  increasing,  in  a  remarkable  manner,  the  action  of  the  arteries. 
Erection,  always  proportioned  to  the  degree  of  the  stimulus,  ceases, 
when  the  cause  of  irritation  no  longer  acts  on  the  penis;  in  the  same 
manner  that  an  inflammatory  tumour  is  discussed,  when  the  cause  is  re- 
moved*. In  this  voluptuous  dilatation,  the  urethra  is  brought  into  a  state 
of  erection,  being  put  on  the  stretch  by  the  penis  which  is  elongated,  its 
curves  are  straightened,  the  irritation  is  propagated  from  the  external  to 
the  internal  parts,  to  the  vesiculse  seminales  and  the  testicles.  These 
swell,  and  their  secretion  is  increased,  as  they  receive  a  gentle  degree  of 
motion  from  the  action  of  the  scrotum,  which  becomes  wrinkled  and 
draws  them  up  towards  the  abdomen,  and  by  the  action  of  the  cremaster 
muscle,  whose  expansion  formsbetween  the  tunica  vaginalis  and  the  dar- 
tos,  what  has  been  improperly  called  the  tunica  erythroidea  ;  they  empty 
themselvess  with  the  greater  ease  along  the  vasa  deferentia,  which  de- 
crease in  length,  as  the  testicles  rise,  and  which  participate  in  the  con- 
cussion affecting  these  organs. 

The  concussions  of  the  cremaster  on  the  testicle,  or  on  the  vassa  defe- 
rentia, promote,  in  so  important  a  manner,  the  secretion  and  excretion  of 
the  semen,  that  this  little  muscle  is  fonnd  in  animals  whose  testicles  never 
leave  the  abdomen,  but  remain  within  that  cavity  on  the  sides  of  the  lum- 
bar region,  as  was  observed  by  Hunter  in  the  hedge-hog  and  the  ram. 
This  fact  of  comparative  anatomy  shows  that  the  cremaster  is  of  use,  not 
merely  in  suspending  the  testicles,  as  its  name  indicates,  since  in  the  ani- 
mals above-mentioned  they  return  into  the  abdomen  towards  the  organ 
on  which  they  are  to  act. 

When  irritation  is  carried  to  a  certain  length,  it  acts  on  the  vesicu- 
lae  seminales,  and  these  on  the  fluid  which  fills  their  cavity,  and  they 
expel  it,  by  the  spasmodic  contraction  of  their  membranous  parietes,  as- 
sisted, in  this  excretion,  by  the  levatores  ani.  (CCI.)  The  prostrate 
gland  and  the  mucus  glands  of  the  urethra  furnish  a  viscid  substance,  cal- 
culated to  promote  the  evacuation  of  the  seminal  fluid,  which  is  emitted 
in  jets,  more  or  less  rapid. 

CCIV.  The  human  semen  is  never  emitted  in  a  state  of  purity,  that 
is,  such  as  it  is  prepared  by  the  testicles  :  it  is  even  conjectured,  that  the 
mucous  fluid  of  the  vesiculae  seminales  forms  the  greatest  part  of  it.  It 
is  this  mucous  which  eunuchs  emit  in  considerable  quantity.  The  fluid 
secreted  by  the  prostrate  gland  and  by  the  mucus  glands  of  the  urethra, 
affect  it,  likewise,  by  uniting  with  it. 

On  being  received  into  a  vessel,  it  exhales  a  peculiar  smell  like  that  of 
the  pollen  of  a  great  number  of  plants,  for  example,  of  the  chesnnt-tree. 
It  consists  of  two  parts,  the  one  thick  and  in  clots,  while  the  other  is  vis- 
cid, white,  and  more  fluid.  The  proportion  of  the  fluid  to  the  semi-con- 
crete part  is  greater,  in  proportion  as  the  person  is  weaker,  and  as  the 
emission  of  semen  is  more  frequently  repeated.  It  soon  liquifies,  by 
losing  part  of  its  weight,  which  always  exceeds  that  of  water  in  which  it 


*  The  animal  heat  is  somewhat  augmented,  during  erection,  as  in  inflammation.  The 
temperature  of  the  blossoms  of  tire  arum  rises  several  degrees  above  that  of  the  atmos- 
phere, at  the  moment  of  impregnation. — 


'389 

becomes  soluble,  though  it  \vas  not  so  at  first.  On  being  analyzed  by  M. 
Vauquelin,  it  was  found  to  contain  of  water  90  centimes — of  animal  mu- 
lage  6— phosphate  of  lime  3 — soda  1.  It  is  in  consequence  of  this  last 
alkali,  that  it  is  enabled  to  turn  syrup  of  violets  to  a  green  colour,  The 
animal  mucilage  is  not  pure  albumine,  but  rather  a  gelatinous  mucus,  on 
which  the  qualities  of  the  semen  appear  particularly  to  depend,  such  as 
its  insolubility  in  water,  its  odour,  and  spontaneous  liquefaction. 

On  being  examined  with  the  microscope,  the  semen  is  seen  to  contain 
small  animalcules,  with  a  rounded  head,  a  tapering  tail,  and  moving  with 
rapidity.  Is  the  liquefaction  of  the  glutinous  and  viscid  parts  of  the 
semen,  owing  to  the  motion  of  these  creatures  ?  These  microscope  ani- 
malcules are  to  be  detected  in  the  semen  only  at  the  period  of  puberty*. 
It  has  been  thought  that  they  shunned  the  light:  authors  have  even  gone 
the  length  of  describing  their  ways  and  then'  diseases.  The  imagination 
has  had  much  to  do  with  all  that  naturalists  have  fancied  they  saw  in 
these  creatures,  which  they  made  subservient  to  theirexplanationsof  the 
mechanism  of  reproduction*  However,  it  must  be  confessed,  that  in  all 
the  animal  fluids,  and  in  the  juices  of  many  plants,  a  certain  number  of 
these  animalcules  may  be  detected  by  means  of  the  microscope. 

A  spasmodic  contraction  affects,  during  the  expulsion  of  the  semen,  not 
only  the  organs  of  generation,  but  the  whole  body  participates  in  the  con- 
vulsive state,  and  the  moment  of  emission  is  accompanied  by  a  commotion 
of  all  its  parts ;  so  that  it  should  seem,  says  Bordeu,  that  in  that  instant, 
Nature  forgot  every  other  function,  and  was  solely  engaged  in  collecting 
her  strength  and  directing  it  to  one  organ.  This  general  spasm,  this,  as 
it  were,  epileptic  convulsion,  is  followed  by  universal  depression  ;  this 
physical  lassitude  is  attended  with  a  sensation  of  sadness,  which  is  not 
without  enjoyment.  Does  this  peculiar  sensation,  which,  according  to 
Lucretius,  mingles  grief  with  the  most  lively  enjoyment  of  which  we  are 
capable,  depend  on  the  fatigue  of  the  organs,  or,  in  truth,  as  some  meta- 
physicians have  imagined,  on  the  confused  and  distant  notion  that  occurs 
to  the  soul  of  its  own  dissolution  ? 

^  The  penis  does  not  enter  the  uterus,  though  the  semen  does.  The  os 
tincse  offers  too  small  a  slit,  and  its  thick  edges  are  besides  in  contact.  It 
would  be  difficult  to  conceive  that  this  straight  passage  should  admit 
even  the  animal  fluid,  if  it  were  not  known  that  in  the  moment  of  copu- 
lation, the  uterus,  from,  irritation,  draws  together,  and  inhales,  by  real 
suction,  the  semen  which  it  craves.  Plato  compared  this  organ  to  an  ani- 


*  The  author  states  in  his  last  edition,  on  the  authority  of  one  observer  only,  that  ani- 
malcule are  not  found  in  the  semen  of  individuals  affected  with  syphilis.  He  also  ob- 
serves, that  he  has  frequently  had  reason  in  the  course  of  his  practice  to  impute  sterility 
in  the  male  to  the  existence  of  the  lues  venerea  ;  this  latter  circumstance,  however,  may 
be  otherwise  explained  than  by  supposing  that  the  seminal  animalculae  are  not  genera- 
ted during-  this  disease.  Indeed  the  existence  of  those  animalcule  is  a  matter  of  much 
doubt.  We  believe  that  what  has  been  usually  supposed  to  be  such,  are  nothing  more 
than  the  minute  portions  of  some  one  of  the  very  different  secretions,  mentioned  above, 
as  constituting  the  seminal  fluid,  in  the  act  of  move  intimate  mechanical  mixture,  or  of 
union,  with  those  of  the  others.  The  appearance  of  animalcules  may  be  also  exhibited 
by  the  secretion  of  a  single  organ  or  part ;  for,  as  all  secreted  fluids  are  not  actually  ho- 
mogeneous, their  minute  particles,  which  differ  in  colour,  consistence,  &c.  from  the 
more  abundant  and  more  aqueous  portion,  would  very  probably  give  rise  to  the  decep- 
tion in  question. —  Copland. 

The  recent  researches  of  Prevost  and  Dundas  have  incontestibly  established  the  fact 
of  the  existence  of  these  aTumalculse.—Go 


396 

inal  living  within  another  animal,  controlling  all  the  actions  of  the  living 
economy,  burning  to  sate  itself  with  the  liquor  of  the  male,  and  digesting 
it  to  form  a  new  individual. 

The  great  thickness  of  the  cervix  of  the  uterus  has  given  room  for 
reasonable  doubt,  if  its  orifice  could  dilate  sufficiently  to  admit  a  fluid  of 
the  consistency  of  semen,  Some,  therefore,  have  thought  that  it  was  not 
this  fluid  itself  that  penetrated  into  the  cavity  of  the  uterus,  but  the  sub- 
tlest of  its  parts,  the  most  spiritualized,  a  prolific  vapour,  to  which  they 
have  given  the  name  of  aura  seminalis  ;  but,  besides  that  the  semen  has 
been  found  in  the  uterus,  in  animals  opened  immediately  after  copulation, 
Spallanzani,  in  his  experiments  on  the  fecundation  of  frogs,  of  salaman- 
ders, and  toads,  perceived  that,  to  enable  the  eggs  to  produce,  it  was  not 
enough  to  expose  them  to  the  vapour  which  rises  from  the  seminal  fluid 
of  the  male  :  and  that  nothing  was  effected,  unless  the  fluid  semen  actually 
touched  them,  though  in  ever  so  small  a  quantity. 

It  has  been  said,  that  the  uterus  dilates  to  receive  the  semen,  constricts 
itself  to  retain  it,  and  that  this  spasmodic  contraction  of  the  uterus,  felt, 
as  Galen  assures  us,  by  women,  who  preserve  enough  sang-froid  to  make 
observations  in  that  situation,  was  the  most  undoubted  sign  that  could  be 
had  of  the  success  of  the  copulation.  It  is,  no  doubt,  to  ensure  this  re- 
tention, that  it  is  customary  to  throw  cold  water  on  the  females  of  some 
domestic  animals,  when  they  go  too  eagerly  to  the  male.  The  spasm  of 
the  skin,  occasioned  by  the  cold  striking  it,  affects  the  uterus,  and  hin- 
ders the  flowing  back  of  the  semen  which  has  been  thrown  into  its  ca- 
vity. 

It  has  also  seemed,  that  women  conceive  more  easily,  for  a  little  time 
after  menstruation  ;  when  the  mouth  of  the  uterus  is  less  exactly  closed 
than  usual. 

The  seminal  fluid,  thrown  into  the  cavity  of  the  uterus,  passes  along 
the  fallopian  tubes  to  the  ovaria.  It  does  not  diffuse  itself  in  the  cavity 
of  the  abdomen,  because  the  membranous  duct  seizes  the  ovarium,  which 
corresponds  to  it,  grasps  it  closely,  and  establishes  an  uninterrupted  canal, 
from  this  organ  to  the  uterus.  The  ovarium,  bedewed  by  the  semen,  ir- 
ritated by  its  contact,  lets  a  fluid  escape,  or  perhaps  a  little  ovum,  which 
passes  into  the  uterus,  the  same  way  that  the  semen  reached  itself*.  All 


*  The  account  here  given  of  the  fecundation  of  the  ovum,  seems  to  us  exceedingly 
erroneous,  and  as  this  is  a  point  of  some  interest,  we  will  not  too  hastily  dismiss  it. 

It  is  our  intention,  first,  to  show  that  the  semen  does  not  enter  the  cavity  of  the  ute- 
rus, much  less  that  it  reaches  the  ovary.  Those  who  differ  from  us  on  this  subject,  have 
mostly  insisted  that  the  semen  is  thrown  into  the  uterus,  by  injection  from  the  penis. 
True  it  is,  that  some  other  modes  have  been  suggested,  but  they  are  really  so  ridiculous, 
as  to  be  wholly  unworthy  of  criticism. 

That  the  male  organ  is  endowed  with  a  considerable  projectile  power,  cannot  be  de- 
nied. It  is  very  conspicuously  evinced,  by  the  impetus  with  which  the  urine  is  dis- 
charged. 

But  admitting,  that  by  an  unusually  vigorous  impulse,  it  were  projected  as  far  as  the 
uterus,  how  could  it  enter  into  the  cavity  of  that  viscus  ?  Let  it  be  recollected  that  the 
os  tincae,  at  least,  in  the  virgin  state,  is  nearly  as  small  as  the  opening  of  the  urethra  in 
the  male,  and  is  not  placed  in  the  immediate  axis  of  the  vagina,  but  is  inclined  more  or 
less  to  the  one  or  the  other  side,  or  towards  the  sacrum.  The  apertures  of  the  two 
organs,  therefore,  are  not  in  opposition.  But  this  is  not  all.  The  os  tineas  is  for  the 
most  part  filled  with  a  thick  glutinous  matter,  capable  of  considerable  resistance.  Where 
it  is  wanting,  as  is  generally  the  case  in  the  virgin  uterus,  the  hard,  unyielding  lips  of 
the  tinea  are  so  closely  approximated  as  to  be  nearly  closed. 

Nor  arc  these  the  only  obstacles  to  the  passage  of  the  semen.     The  canal  leading- 


391 

that  remains  to  be  said,  concerning  the  mechanism  of  generation,  must 
not  be  delivered  as  real  but  merely  as  probable,  such  is  is  the  darkness 
with  which  Nature  has  chosen  to  envelope  this  great  mystery  of  the  living 
economy*. 


through  the  neck  of  the  uterus,  is,  in  the  unimpregnated  state  of  the  organ,  probably  not 
larger  than  a  common  size  probe.  That  portion  of  the  canal  called  the  straight,  is  still 
more  contracted.  Besides,  along  the  whole  course  of  the  canal,  there  are  striae,  or 
wrinkles,  and  between  which,  glands,  secreting  mucus  obviously  calculated  for  the  pur- 
pose of  additional  obstruction.  Even  the  proper  cavity  of  the  uterus  itself,  is  so  ex- 
tremely shallow  that  its  two  surfaces  are  nearly  m  contact. 

Such  are  the  impediments  incident  to  a  perfectly  natural  and  healthy  condition  of  the 
parts.  To  these  may  be  added  others  resulting  from  morbid  derangement,  or  conge- 
nital deformities,  and  which  are  found  to  exist  as  well  in  the  males  as  the  female  organs. 

1.  The  penis  has  its  power  of  ejecting  the  semen,  destroyed  or  abridged  by  trunca- 
tion, by  strictures,  by  anomalous  openings  along  the  course  of  the  urethra,  or  by  debility 
and  relaxation. 

2.  The  vagina  is  obstructed  or  shut  up  by  cohesion  of  its  sides,  by  membranes  of  ad- 
ventitious growth,  or  by  tumors. 

3.  The  os  tincx  is  sometimes  discovered  impervious,  either  from  original  imperfec- 
tion, or  by  the  process  of  inflammation,  and  is  occasionally  rendered  utterly,  inaccessi- 
ble to  the  semen,  by  the  obliquities,  retroversions,  or  prolapsions  of  the  wombf. 

These  facts  very  clearly  demonstrate,  that  conception  can  take  place  though  the 
semen  may  be  deposited  merely  within  the  vulva,  and  seem  almost  to  warrant  the  con- 
clusion, that  it  never  does,  as  a  natural  event,  reach  the  cavity  of  the  uterus.  Lest, 
however,  they  may  not  appear  to  others  in  the  same  strong  light,  in  which  they  present 
themselves  to  us,  we  will  bring  to  their  aid  some  further  evidence. 

Experiments  have  been  resorted  to  in  order  to  decide  this  point.  They  have  been 
made  by  Harvey,  De  Graat,  Lewenhoeck,  Haller,  and  Heighten.  Different  animals 
were  the  subject  of  these  experiments.  The  doe,  the  cow,  the  ass,  the  ewe,  the  bitch, 
the  rabbit,  were  all  inspected  immediately,  or  at  remote  periods,  after  connexion  with 
the  male,  and  never  except  in  one  instance,  could  the  semen  be  traced  beyond  the  va- 
gina. By  Haller  it  is  stated,  that  he  once  detected  the  semen  in  the  uterus  of  a  sheep 
forty-five  minutes  post  coitiim.  But  this  is  a  solitary  exception,  to  the  numerous  obser- 
vations both  of  himself  and  others  and  which  can  claim  little  consideration,  especially 
when  it  is  known  that  such  a  result  was  essentially  necessary  to  the  maintenance  of  a 
favourite  hypothesis. 

As  auxiliary  to  this  single  experiment  of  Haller,  it  is,  however,  urged  that  Morgagni 
saw  the  semen  in  the  uterus,  and  Ruysch  in  the  fallopian  tube  of  the  human  species* 
Without  impeaching  the  veracity  of  either  of  these  illustrious  men,  we  may  be  permit- 
ted to  remark,  that  their  observations  have  never  been  confirmed,  and  that  under  the 
circumstances  in  which  they  were  made,  it  is  reduced  almost  to  a  moral  certainty  that 
they  mistook  for  semen  what  was  in  reality  the  mucus  of  the  parts.  But,  conceding  to 
these  alleged  facts  all  that  can  reasonably  be  required,  what  do  they  amount  to  ?  Con- 
trasted with  the  vast  mass  of  counter  evidence,  they  dwindle  into  insignificance  and  will 
not  weigh  as  dust  in  the  scale. 

It  appearing,  therefore,  that  the  semen  does  not  enter  into  the  uterus,  it  becomes  su- 
perfluous to  inquire  respecting  the  practicability  of  its  conveyance  by  the  fallopian  tubes. 
The  latter  problem  is  merged  in  the  former.  But  to  silence  all  cavils,  we  will  give  the 
question  a  cursory  examination. 

That  the  fallopian  tubes  are  not  subservient  to  this  purpose,  is  very  distinctly  indica- 
ted by  the  peculiarity  of  their  structure.  Commencing  with  an  aperture  so  very  minute, 
as  hardly  to  admit  a  common  bristle,  the  canal  gradually  enlarges,  and  finally  terminates 
in  a  wide  and  patulous  mouth.  Now,  were  they  destined  to  convey  from  instead  of  to 
the  utenis,  would  not  the  construction  be  directly  the  reverse  of  what  it  is  ?  We  know 
that  they  conduct  the  product  of  the  ovary  to  the  womb,  and  we  see  that  the  extremity 

*  See  APPENDIX,  Note  1 1. 

f  Each  of  the  above  positions  is  supported  by  cases  to  be  found  in  the  writings  of 
Harvey,  Morgagni,  Hildanus»  Ruysch,  Mauriceau,  Simpson,  Guillemeau,  Haller,  and  in 
the  periodical  journals. 


After  distinguishmgthe  true  from  the  probable,  an  indispensable  duty 
in  every  science  of  facts  and  observations,  like  physiology,  I  shall  pro- 
ceed to  state  the  hypothesis,  which  appears  to  me  the  likeliest,  on  the 
manner  in  which  the  two  sexes  concur  in  the  production  of  the  new 
being. 

CCV.  The  foetuses  pre-exist  in  the  ovaria  of  the  females,  not  that  they 
are  there  since  the  creation  of  the  world,  as  Bonnet  believed,  and  all  who 
embraced  the  doctrine  of  that  metaphysical  naturalist  j  but  the  ova  con- 
taining his  germs  are  formed  by  the  proper  action  of  the  ovariutn  which 
secretes  them,  a  fresh  proof  that  all  the  phenomena  of  organized  bodies, 
whether  for  the  preservation  of  the  species  or  of  the  individual,  are  effect- 
ed in  the  way  of  secretions.  This  ovum,  produced  by  the  elaboration  of 
the  blood  which  the  spermatic  vessels  carry  to  the  ovaria,  contains  the 
lineaments  of  the  new  being ;  but  it  is  only  the  sketch,  or  carcass  of  it,  if 
this  may  be  applied  to  what  has  not  yet  lived.  The  seminal  fluid  must 
bring  it  out  of  this  state  of  inactivity,  and,  with  something  of  an  electri- 
cal power,  waken  it  into  life.  The  eggs  laid  by  a  maiden  hen,  will  never 
hatch,  though  there  are  in  them  the  rudiments  of  the  chick.  The  eggs 
of  a  frog  that  has  been  kept  apart  from  the  male,  during  the  whole  time 
of  spawning,  putrify  in  the  vessel  of  water  they  are  kept  in:  if  the  male, 
on  the  contrary,  if  sprinkled  with  his  semen,  as  they  quitted  her,  they 

is  adapted  to  this  office.  It  is  almost  as  well  ascertained  that  they  convey  nothing-  from 
the  uterus,  and  the  orifice  is  fashioned  accordingly. 

By  assigning  to  the  tube  this  function,  we  moreover  invest  it  with  a  power  of  a  two- 
folti  action,  precisely  opposite,  of  which  there  is  no  analogy  in  the  animal  economy.  The 
inverted  periastalic  motion  of  the  intestines,  comes  nearest  to  an  example,  but  it  will 
not  hold.  The  cases  are  not  parallel,  the  action  of  the  intestine  being  preternatural, 
the  effect  of  violence  and  disease.  It  is  useless,  however,  to  protract  this  discussion,  as 
we  have  proof  at  hand  which  is  absolutely  conclusive.  By  the  experiments  of  Mr. 
Haighton,  it  is  ascertained  that  the  tubes  do  not  change  their  position  to  grasp  the  ma- 
tured vesicle  till  the  whole  process  of  conception  is  consummated  in  the  ovary. 

"I  found,"  says  this  eminent  physiologist,  "  from  a  series  of  observations  made  on 
different  rabbits,  at  every  hour  between  the  1st  and  9th,  that  the  iimbrix  remained 
nearly  in  their  usual  situation,  and  the  only  difference  1  found  in  the  last  hour,  was  a 
greater  turgescency  of  vessels,  as  if  preparatory  to  some  important  action.  I  desisted 
from  this  inquiry  at  the  9th  hour,  because  the  ovaries  bare  evident  marks  of  impregna- 
tion, and  there  appeared  to  be  no  action  in  the  tubes,  by  which  the  semen  could  be 
conveyed  to  them." 

Convinced  that  the  hypothesis  in  its  primitive  shape  was  no  longer  tenable,  some  of 
the  advocates  of  impregnation  by  contact,  have  contended  that  it  is  effected  by  the 
emission  of  subtle  exhalation  from  the  semen,  termed  aura  semitiaUs,  and  which  is  trans- 
mitted through  the  tubes  to  the  ovary.  But  here  they  are  again  met  by  the  whole  body 
of  facts,  and  chain  of  reasoning  which  drove  them  from  their  original  position.  It  has 
indeed,  been  said,  and  with  no  want  of  plausibility,  that  the  volatile  vapours  from  the 
semen  might  penetrate  through  obstructions  which  should  resist  the  semen  itself.  Be 
it  so  :  in  many  instances,  it  might  happen  undoubtedly.  But  still,  how  can  the  cases 
formerly  referred  to,  be  got  over,  where  from  organic  derangement,  the  passages  were 
so  entirely  occluded,  as  to  be  impervious  even  to  air  ? 

Nor  are  these  the  only  difficulties  that  stand  in  the  way  of  this  amended  hypothesis. 
We  are  not  disposed,  however,  to  enter  at  present  into  any  further  detail.  Before  we 
engage  in  a  lengthened  investigation  of  this  sort,  we  require  it  to  be  shown  that  the 
aura  seminalis  has  the  property  of  fecundation.  As  yet,  no  such  proof  has  been  exhibi- 
ted, The  experiments  of  Spallanzani,  and  Hunter,  the  only  ones  which  have  been  made 
on  the  subject,  prove  indeed  quite  the  contrary. — Chapman. 

Dr.  Gartner  of  Copenhagen  has  demonstrated  the  existence  of  ducts  leading  from 
the  ovaries  to  the  uterus  in  the  cow  and  sow,  Dr.  Dewees  of  Philadelphia,  some  years 
ago  published  a  new  theory  of  generation,  which  is  predicated  on  the  existence  of  these 
ducts  between  the  vagina  and  ovaries.  See  ed.  Med.  Journal,  July  1822. — Godman. 


393 

will  speedily  show  some  developement  of  life.  Their  putrefaction  may 
be  prevented,  and  themselves  animated,  by  shedding  on  them  the  sper- 
matic fluid,  obtained  by  the  process  employed  by  Spallanzani,  in  his  ad- 
mirable experiments  on  artificial  impregnation, 

It  is  especially  to  the  labours  of  this  able  observer,  that  we  owe  what 
has  been  unveiled  of  the  mystery  of  generation,  and  of  the  part  which 
each  sex  bears  in  this  function.  It  is  almost  proved.,  that  the  male  co- 
operates in  it,  only  by  supplying  the  vivifying  principle  that  must  ani- 
mate the  individuals  of  which  the  female  furnishes  the  germs;  that  thus, 
his  part  is  the  least  essential.  It  is  not  so  difficult  as  may  be  imagined, 
to  explain  upon  this  system,  the  striking  resemblances  which  are  fre- 
quently seen  between  fathers  and  sons.  The  imperceptible  embryo  has,  at 
most,  the  consistency  of  a  slight  viscous  glue.  Such  a  body  must  be  ex- 
ceedingly impressible,  and  the  semen  of  the  male,  applied  to  its  surface, 
must  impress  on  it  powerful  modifications.  The  action  of  the  fluid  on 
this  yet  tender  embryo  must  be  like  that  of  a  seal,  which  stamps  on  the 
soft  wax  its  own  image.  The  impression  is  the  deeper,  the  resemblance 
the  more  striking,  according  to  the  spirit  and  energy  with  which  the  male 
performed  the  act  of  reproduction. 

The  seminal  fluid  may  not  merely  act  on  the  surface  of  the  gelatinous 
and  nearly  liquid  germ,  and  modify  it  externally*  but  it  may  penetrate  so 
soft  a  substance,  and  impress  it  on  inward  changes.  It  is  thus  that  we 
are  able  to  explain,  not  only  hereditary  likeness,  but  also  hereditary  dis- 
eases. Nevertheless,  it  does  appear,  that  the  interior  parts  are  derived 
chiefly  from  the  female,  while  the  outward  parts  are  especially  influenced 
by  the  male;  for,  when  two  animals  of  different  species  copulate,  their 
mule  resembles  the  sire  outwardly,  and  the  dam  within.  It  is  difficult  to 
show  good  reason  for  the  want  of  the  generative  faculty  in  mules.  Why 
are  their  sexual  parts,  so  well  developed,  altogether  barren?  What  se- 
cret defect  frustrates  their  action?  And  why  do  certain  mules,  among- 
birds,  propagate,  and  in  the  same  manner,  hybrid  plants,  which  are  real 
mules,  and  not  quadrupeds  ? 

The  impregnation  of  the  ovum  is  effected  in  the  ovarium  itself,  to 
which  the  semen  is  conveyed,  as  has  been  said.  The  ovum,  stirred  by  the 
action  of  the  semen,  and  of  the  fallopian  tubs,  detaches  itself  from  the 
organ  which  has  produced  it,  and  descends  into  the  uterus,  by  the  peris- 
taltic contractions  of  the  fallopian  tube.  This  canal  is  susceptible  of  a 
retrograde  motion.  It  may  be  conceived,  by  considering  that  having 
stretched  itself,  by  a  real  erection,  to  convey  the  semen  to  the  ovarium,  it 
must,  in  its  return  upon  itself,  cause  a  flow  of  the  fluid  its  cavity  contains, 
in  a  completely  inverted  direction*.  This  retrograde  motion,  as  Nisbet 
observes,  is  assisted  by  a  sort  of  collapse  succeding  the  excitation  which 
coition  had  produced:  for,  the  experiments  of  Darwin  prove  that  the 
weakness  of  the  vessels  is  the  cause  of  this  mode  of  action  in  their  f>ari- 
etes.  Spongy  as  the  urethra  of  man,  the  fallopian  tube  brings  back  the 
ovum  from  the  ovarium  to  the  uterus.  The  extra  uterine  foetations  afford 
the  proof,  that  matters  are  carried  on  in  the  manner  we  have  stated.  Since 
foetuses  have  been  found  developed,  in  the  ovurium,  in  the  fallopian  tube, 
and,even  in  the  cavity  of  the  abdomen,  when  the  detached  ovum  has 
escaped  from  the  grasp  of  the  corpus  fimbriatumf,  one  must  admit,  that 
it  follows  the  course  which  has  been  described. 

*  See  the  Note  in  the  APPENDIX  on  this  subject. 

f  In  extra  uterine  abdominal  conceptions,  the  ovum  which  the  tube  could  not  hold  or 

3  D 


394 

The  ovaria,  like  the  testicles,  swell  and  enlarge,  at  the  time  of  puberty. 
They  shrink,  and  wither  in  some  sort,  when  the  woman  is  no  longer 
fit  for  conception.  On  examination,  a,  few  days  after  conception,  one  of 
the  ovaria,  larger  than  the  other,  shows  a  little  yellowish  vesicle,  which 
dries  up  in  the  course  of  pregnancy,  so  that,  towards  the  end,  there  re- 
mains nothing  in  place,  but  a  very  small  cicatrix.  Is  this  vesicle,  the 
outermost  covering  of  the  ovum,  in  which  the  germ  is  enclosed,'  and 
which  is  torn  to  allow  its  escape?  The  observations  of  Haller  prove  that 
the  corpus  luteum  is  formed  by  the  remains  of  a  vesicle  that  has  burst  at 
the  moment  of  conception,  and  allowed  the  fluid  it  contained  to  escape. 
In  an  ewe  opened  a  few  minutes  after  coition,  you  may  see,  in  one  of  the 
ovaria,  a  vesicle  larger  than  the  others,  torn  with  a  little  wound,  of  which 
the  lips  are  still  bloody.  Inflammation  comes  on  in  the  torn  coats  of  the 
small  vesicle,  fleshy  granulations  appear,  then  sink,  and  a  scar  shows  the 
place  where  it  had  been.  The  number  of  these  cicatrices  is  proportion- 
ed to  that  of  the  foetuses.  It  is  not  known  how  long  the  germ  detached 
from  the  ovarium  remains  within  the  fallopian  tube,  before  it  reaches  the 
cavity  of  the  uterus.  Valisnieri  and  Haller  had  never  been  able  to  per- 
ceive it  distinctly  in  this  viscus,  before  the  seventeenth  day. 

The  obstruction  of  the  tubes  may,  as  well  as  the  defect  or  diseased 
affection  of  the  ovaria,  cause  barrenness.  Morgagni  speaks,  on  this  head, 
of  certain  courtezans  in  whom  the  tubes  were  entirely  obliterated  by  the 
thickening  of  their  parietes ;  the  consequence,  evidently,  of  the  habitual 
orgasm  in  which  they  had  been  kept,  by  two  frequent  excitation.  The 
structure  of  these  parietes  must  make  obstructions  of  the  fallopian  tubes 
very  easy.  Their  tissue  is  spongy,  vascular,  and  seems  susceptible  of 
erection,  like  the  corpus  cavernosum  of  the  penis  and  of  the  clitoris.— 
Their  internal  coat  (the  .point  of  union  between  the  serous  membrane 
which  lines  the  abdomen,  and  the  mucous  membrane  within  the  uterus) 
partakes  in  the  inflammation  of  both.  I  have  often  been  consulted  by 
young  women  on  the  cause  of  their  sterility:  by  a  close  investigation  of 
the  causes  from  which  it  might  have  arisen,  I  have  always  found  that 
they  had  had,  at  different  periods  of  life,  inflammation  of  the  lower  part, 
of  the  abdomen.  A  young  woman,  after  obstinate  suppression  of  the 
menses,  exhibited  all  the  symptoms  of  inflammation  of  the  peritoneum: 


seize,  rolls  into  the  hypogastric  region,  and  there  adheres  to  some  point  of  the  perito- 
neum. It  is  found  attached  to  the  mesentery,  to  the  colon,  to  the  rectum;,  to  the  ex- 
.ternal  part  of  the  uterus,  growing-  there,  and  developed,  by  the  vascular  communica- 
tion which  takes  place  at  the  adhesion  ;  but  the  vessels  of  the  peritoneum  are  insuffici- 
ent for  the  entire  developement  of  the  foetus,  which  dies,  for  want  of  nourishment,  in 
the  first  months  of  pregnancy.  The  adhesion  of  the  ovum  to  the  peritoneum,  is  easily 
accounted  for,  by  the  irritation  it  occasions  :  it  may  be  considered  as  a  foreign  body,  de- 
termining, by  its  presence,  inflammation  of  the  membrane,  with  which  it  lies  in  contact 
and  uniting  with  it,  because  it 'brings  to  this  act  its  own  share  of  vitality.  It  is  really 
a  union  of 'two  living  parts,  not  unlike  to  that  which  takes  place,  between  the  bleeding 
lips  of  a  wound,  between  the  pleura  pulmonalis,  and  pleura  costalis,  8cc. 

But  as  the  serous  membranes  contain,  in  their  tissue,  capillaries  so  fine,  that  when  in 
a  healthy  state,  the  blood  does  not  show  its  colour  in  them,  their  vessels  never  develops 
themselves,  sufficiently  to  transmit  to  the  ovum,  which  has  adhered  to  them,  a  due  sup- 
ply of  this  fluid.  The  mucous  membranes  receiving  more  blood,  are  able  to  supply 
more;  but  the  placenta  cannot  adhere  to  them  in  extra  uterine  conception.  The  mem- 
brane which  lines  the  tube,  belongs,  in  fact,  as  much  to  the  serous  as  to  the  mucous  mem- 
branes; it  establishes,  as  is  well  known,  the  only  point  of  communication  there  is  between 
the  two  kinds  of  membranes. — Author's  Note. 


395 

a  year  afterwards  she  married,  but  never  became  pregnant,  A  woman 
recovered  from  puerperal  fever,  ensuing  upon  a  very  difficult  first  labour; 
from  that  time,  with*all  the  appearance  of  the  stoutest  health,  she  has 
never  been  again  a  mother. 

Do  the  two  testicles,  and  the  two  ovaria,  contain  the  separate  germs  oi' 
males  and  females  ?  Are  these,  as  has  been  guessed,  contained  in  the  le/t 
ovarium,  and  males  in  the  right?  and  may  we  procreate  sexes  at  plea- 
sure, by  varying  the  attitude  of  copulation  ?  This  old  opinion,  lately  re- 
vived, besides  wanting  all  foundation,  is  formally  confuted  by  facts  :  no- 
thing is  more  common  than  to  see  men  who  have,  from  some  accident, 
lost  a  testicle,  procreating  sexes  indifferently.  Women,  with  an  ovarium 
deficient,  or  the  fallopian  tube  obliterated  on  one  side,  have  produced 
both  boys  and  girls.  Dr.  Jadelot  has  presented  to  the  society  of  the 
School  of  Medicine,  in  Paris,  a  uterus,  wanting  the  right  tube  and  ovari- 
um; and  nothing  indicated  that  they  had  ever  existed.  On  inquiry  con- 
cerning this  woman,  it  appeared  that  she  had  been  delivered  of  a  boy  and 
two  girls:  Haller  quotes  similar  cases.  The  cause,  then,  which  deter- 
mines the  sex,  altogether  eludes  our  investigation.  Does  that  one  of  the 
two,  who  exerts  most  energy  in  the  act  of  coition,  impress  his  sex  on  the 
offspring?  I  cannot  tell;  but  I  think  I  have  observed  that  the  marriage 
of  young  people,  where  both  are  glowing  with  love  and  youth,  most  fre- 
quently produce  daughters,  whilst  boys  are  ordinarly  the  consequence  of 
the  union  of  a  middle  aged,  or  elderly  man,  with  a  younger  woman. 

CCVI.  Systems  of  generation.  The  antique  system  of  the  mixture 
of  the  semen  in  the  cavity  of  the  uterus,  set  forth  in  the  writings  of  Hip- 
pocrates and  Galen,  is  still  that  of  many  physiologists.  In  this  system, 
the  mixed  fluid  may  be  considered  as  an  extract  from  all  parts  of  the 
body  male  and  female.  A  generative  faculty*  disposes  them  suitably  for 
the  formation  of  the  new  individual.  Buffon  has  further  particularized 
the  facts  which  this  hypothesis  requires,  and  displays  its  improbability. 
Each  part,  he  says,  furnishes  molecules,  which  he  calls  organic,  and 
these 'molecules,  coming  from  the  eyes,  the  ears,  Sec.  of  the  man  and  the 
woman,  arrange  themselves  round  an  internal  mould,  of  which  he  admits 
the  existence,  which  mould  forms  the  basis  of  the  edifice,  and  comes 
from  the  male  probably,  if  it  be  a  boy,  from  the  female,  if  a  girl.  Rea- 
son rejects  a  theory  which  gives  no  explanation  of  the  production  of  the 
placenta,  and  of  the  membranes  covering  the  foetus  :  it  is  moreover  di- 
rectly disproved  by  the  good  conformation  of  children,  born  of  parents, 
who,  not  happening  to  have  certain  organs  and  limbs,  could  not  certaintly 
supply  the  proper  molecules  for  their  formation  in  the  child. 

The  system  of  the  ovarists,  which  at  this  time  stands  highest  in  favour, 
numbers  amongst  its  supporters,  Harvey,  Stenon,  Malpighi,  Valisni- 
eri,  Duhamel,  Nuck,  Littre,  Swammerdam,  Haller,  Spallanzani,  Bonnet, 
&c.  These  admit  the  distinction  of  animals  into  oviparous  and  vivipa-* 
rous,  in  this  sense  only,  that  these  last  hatch  within,  and  break  their 
shell  before  they  are  brought  forth.  Lastly,  Leeuwenhoek,  Hartsoeker, 
Boerhaave,  Mery,  Werheyen,  Cowper,  &c.  have  added  to  the  opinion  of 


*  All  thatBlumenbach  has  said,  on  the  force  of  formation,  (JHisua  formatimt*)  Applies 
to  this  generative  faculty;  it  is  only  a  new  name  given  to  an  old  idea. — .Author's  J\'ot*. 

This  "  generative  faculty,'*  will  doubtless  remind  the  reader  of  the  "  dormitive  fa- 
.culty"  by  which  Moliere's  new  made  fioctor  explained  the  action  of  opium.— Gwlman. 


396 

the  ovarists,  that  the  seed  of  the  male  contains  a  multitude  of  spermatic 
animalcules,  all  capable  of  becoming1,  by  developement,  beings  similar  to 
their  father.  These  animalcules  push  forward,  along  the  tubes,  upon  the 
ovaria  :  there  a  general  engagement  takes  place,  in  which  all  are  slain, 
save  only  one,  who,  master  of  the  field  of  battle,  finds  the  triumph  of  his 
victory  within  the  ovum  that  has  been  prepared  for  him.  This  system, 
\vnich  is  not  the  most  probable  in  the  world,  assigns  to  the  male  the 
greater  part  in  the  work  of  generation,  since  the  female  is  made  to  fur- 
nish merely  the  coverings  of  the  foetus. 

It  would  be  to  no  purpose  to  unfold,  more  at  large,  opinions  hazarded 
on  a  subject  so  obscure.  What  I  have  said  is  enough  to  show  that  those 
parts  of  nature  which  most  obstinately  elude  our  curiosity  and  afford 
most  scope  to  our  imagination,  are  those  whfch  men  believe  they  know 
the  best,  and  on  which  they  speak  with  most  confidence  and  prolixity: — 
so  true  is  it,  as  Condillac  has  observed,  that  we  have  never  so  much  to 
say,  as  when  we  set  out  from  false  principles*. 


*  Numerous  as  are  the  theories  which  have  been  advanced  on  the  subject  of  gene- 
ration, they  may  all,  as  mere  varieties,  (or  at  least  such  as  are  worthy  of  attention,)  be 
very  properly  reduced  under  two  leading  heads  or  general  divisions. 

1.  Doctrine  of  Palengenesis. 

2.  Doctrine  of  Epigenesis. 

The  first  of  these  doctrines  suppose  the  pre-existence  of  germs.  It  is  of  great  anti- 
quity, and  in  its  descent  to  us  has  undergone  some  slight  modifications-  By  most  of 
the  early  philosophers  it  was  taught,  "  That  these  germs  created  with  the  beginning 
of  things,  were  scattered  throughout  the  world,  but  ultimately  meeting-  with  appropri- 
ate genital  organs,  effected  a  lodgment  therein,  and  became  fit  for  developement." 

As  soon,  however,  as  the  moderns  entered  into  speculations  of  this  nature,  the  hypo- 
thesis received  a  correction  which,  in  part,  divested  it  of  its  absurdity.  Denying-  that 
these  germs  wandered  about  "  in  quest  of  an  habitation  and  a  home,'*,  it  was  now,  on 
•;he  contrary,  maintained,  "  That  all  of  the  same  species,  were  ab  initio  neatly  incased, 
one  within  another,  so  that  the  first  parent,  animal  and  vegetable,  contained  the  germs 
of  each  succeeding-  generation,  and  which  to  be  evolved  required  only  the  seminal  im- 
pulse of  the  male." 

This  doctrine  of  evolution  had  been  hardly  revived,  when  two  sects  arose,  who  urged 
their  respective  opinions  with  all  the  zeal,  all  the  ardour,  and  all  the  pertinacity  of 
party  controversialists.  They  differed,  however,  only  on  a  single  point.  By  the  one 
side  it  was  maintained,  that  the  germs  were  furnished  by  the  female,  and  by  the  other 
that  they  proceeded  from  the  male. 

The  former  of  these  opinions  was  brought  into  repute  by  Fabricius  ab  Aquapendente, 
so  called  from  the  place  of  his  nativity.  Having-  ascertained,  as  he  thought,  by  a  series 
of  experiments  on  the  eg-g,  that  it  contained  a  pre-existing-  embryon,  he,  with  a  nume- 
rous train  of  disciples,  pushed  their  investigations,  and  finally  detected,  or  pretended 
to  detect,  ova  also  in  the  viviparous  animals. 

Enamoured  of  this  boasted  discovery,  the  celebrated  Harvey  became  one  of  the 
warmest  and  most  strenuous  supporters  of  the  hypothesis  to  which  it  led.  "  Omnia  ex 
ovo." 

This  brief  aphorism,  which  escaped  from  him  in  the  enthusiasm  of  his  devotion,  suf- 
ficiently marks  his  impressions  on  the  subject.  The  only  distinction,  indeed,  which 
he  admits  in  the  generative  process  of  the  two  classes  of  animals,  is,  **  That  in  the  vi- 
viparous, the  feet  us  begins  to  exist,  increases,  and  completes  its  growth  in  the  uterus; 
whereas,  in  the  oviparous,  the  embryo  exists  in  the  egg  in  the  body  of  the  hen,  but 
does  not  become  a  fccttts  till  expelled,  and  is  hatched  into  life  by  incubation." 

The  ovular  doctrine  was  first  arranged  by  Lewenhoek,  Who  made  the  discovery  of 
the  spermatic  animalcules  in  the  male  seed-  By  him  and  his  followers,  the  existence 
of  ova  in  viviparous  animals  was  speedily  and  satisfactorily  confuted.  They  demon- 
strated to  entire  conviction,  that  what  had  been  taken  for  true  ova  were  the  mere  vesi- 
cles of  the  ovary,  which  have  no  resemblance  to  an  egg,  being  merely  cups  or  reser- 
voirs of  a  fluid,  which  after  fecundation  is  discharged  and  conveyed  by  the  fallopian 


397 

CCVII.  Of  gestation.  From  the  moment  of  conception,  there  begins 
in  woman,  both  in  the  motion  of  the  solids,  and  the  composition  of  the 
fluids,  a  remarkable  alteration.  The  change  that  has  taken  place  shows 
itself  in  all  her  functions:  she  exhales  a  peculiar  odour;  the  child  she 
suckles  refuses  the  breast,  or  takes  it  with  reluctance,  an$  soon  falls  away, 
if  left  in  the  hands  of  such  a  nurse. 

Nature,  occupied  with  her  work,  seems  to  forget  every  thing  else,  to 
bring  it  to  perfection.  It  has  been  observed,  that  in  times  of  contagious 
diseases,  even  where  the  plague  raged,  pregnant  women  were  least  ex- 


tube  to  the  cavity  of  the  uterus.  They  further  proved,  that  previously  to  impregnation 
nothing  like  a  germ  could  be  found  even  in  the  real  egg's,  but  that  there  is  placed  on 
the  vitellus,  a  small  vesicle,  the  cicatricula,  containing  a  fluid  of  the  same  nature,  and 
destined  for  the  same  end  as  that  in  the  vesicle  of  the  ovary.  The  only  difference, 
therefore,  in  this  respect,  between  the  egg  and  ovary,  according  to  this  sect,  is,  that 
the  former  has  a  single,  while  the  latter  has  a  cluster  of  vesicles. 

By  this  doctrine  of  spermatic  worms,  which  completely  usurped  the  place  of  the  ovu- 
lar  doctrine,  and  which  acquired  for  a  time  an  undisputed  ascendency  in  the  medical 
and  philosophical  schools,  it  was  affirmed,  that  these  seminal  vermiculi  are  living  minia- 
tures of  the  animal  from  which  they  are  derived,  exacting  only  from  the  female  a  ma- 
trix  for  nourishment,  evolution  and  growth. 

Though  the  ovular  doctrine  was  thus  subverted  by  Lewenhoek  and  his  auxiliaries,  it 
after  a  while  again  revived,  under  the  auspices  of  Haller,  so  far  at  least,  as  to  suppose 
the  pre-existence  of  a  germ  in  the  female,  and  soon  received  the  distinguished  support 
of  Bonnet,  Spallanzani,  Hunter,  &c.  Being  restored  in  a  more  enlightened  age,  it  of 
course  was  stripped  of  most  of  those  extravagancies  which  had  before  detracted  so 
much  from  its  merit.  Agreeing  in  the  fundamental  principle  of  the  doctrine,  these 
physiologists  entertained  some  difference  of  opinion  as  to  the  origin,  the  existence  and 
develop ement  of  the  germs.  They  all,  however,  maintained  «  that  the  germ,  as  the 
exact  miniature  of  the  animal  or  vegetable  to  which  it  belongs,  exists  in  the  female 
prior  to  fecundation,  requiring  only  the  stimulus  of  the  male  seed  to  excite  it  into  life, 
&c.  8cc. 

By  thus  narrowing1  the  definition  of  the  doctrine,  they  presented  it  in  a  guise  exceed- 
ingly alluring,  and  rested  its  vindication  on  a  collection  of  experiments  and  observa- 
tions, in  appearance,  the  most  definite  and  conclusive.  These,  however,  on  a  closer 
examination,  exhibit  a  very  different  aspect,  so  much  so  indeed  that  a  large  number  of 
distinguished  physiologists  have  been  induced,  upon  the  most  diligent  scrutiny,  to 
question  altogether  the  pre-existence  of  germs.  It  would  be  wholly  inconsistent  with 
our  limits  to  detail  the  arguments  and  reasonings  which  have  been  employed  by  the 
adverse  parties  in  this  interesting  controversy.  We  proceed  next,  therefore,  to  the 
doctrine  of  Epigenesis. 

Discarding,  as  we  have  already  hinted,  the  notion  of  the  pre-existence  of  germs,  it 
presumes  that  "  the  prepared,  but  at  the  same  time  unorganized  rudiments  of  the  foetus, 
first  begin  to  be  gradually  organized  when  they  arrive  at  their  place  of  destination,  at  a 
due  time,  and  under  the  necessary  circumstances."  This  is  the  definition  of  a  learned 
writer.  The  doctrine,  however,  may  be  more  distinctly  enunciated.  We  would  say, 
that,  denying  the  pre-existence  of  germs  in  either  parent,  the  doctrine  of  Epigenesis 
supposes,  that  the  fluid  contained  in  the  ovarian  vesicle  is  the  rude  elementary  matter, 
which,  after  impregnation,  becomes  organized  into  an  embryon  by  the  energies  of  the 
semen  masculinum.  The  primary  traces  of  this  doctrine  are  to  be  niet  with  in  the 
writings  of  Aristotle.  The  prevailing  opinion  on  the  subject  of  generation,  in  the  time 
of  this  eminent  philosopher  was,  that  each  sex  furnishes  semen,  and  that  the  embryon 
results  from  an  admixture  of  the  two  fluids  in  the  cavity  of  the  uterus.  After  confuting 
the  popular  idea  of  women  having  semen,  he  asserted"  that  they  contribute  nothing  to- 
wards conception,  except  the  menstrual  blood  ;  that  the  rudiments  of  the  embryon  are 
derived  from  the  menses,  and  are  vivified  and  put  together  by  a  plastic  power,  which 
he  imputed  to  the  semen.  With  various  modifications  this  hypothesis  has  been  handed 
down  to  us.  It  would  be  tedious  and  impossible  to  point  out  all  the  shapes  which  at 
different  times  it  has  assumed.  Of  late  its  most  able  and  determined  supporter  is  Bin- 
menbach,  to  whose  system  of  Physiology,  and  Essay  on  Generation,  we  must  refer  such 
of  our  readers  as  are  desirous  of  further  information  on  this  subject. — Chapman. 


39$ 

posed  to  infection  ;  but,  at  the  same  time,  when  they  are  seized  with  af- 
fections, which  in  other  persons,  or  at  another  season,  would  be  without 
danger,  they  sink  under  them,  because  these  diseases,  though  at  first  very 
slight,  easily  put  on  a  malignant  character.  The  progress  of  mortal  dis- 
eases is  retarded  ;  a  phthisical  woman,  and  who  has  only  a  few  months 
to  live,  shall  prolong  her  life  through  the  whole  term  of  gestation.  The 
consolidation  of  fractures  is  nothing  slower,  though  Fabricius  Hildanus 
pretends  that  the  state  of  pregnancy  pats  a  complete  stop  to  it. 

I  have  never  been  able  to  find  any  difference  in  the  time  of  formation  of 
callus,  between  pregnant  women  and  others.  M.  Boyer  avows  the  same 
opinion*.  Among  the  authors  who  have  asserted  that  fractures  could  not 
consolidate  during  pregnancy,  some  have  conjectured  that  this  depends 
on  Nature;  who  is  busy  in  directing  the  humours  to  the  uterus,  forget- 
ting, in  some  sort,  every  other  function,  and  omitting  to  institute  the  pro- 
cess necessary  to  the  cure.  But  as  we  shall  see,  whatever  may  be  the 
importance  of  the  uterus,  charged,  during  pregnancy,  with  the  fruit  of 
conception,  the  foetus  is  merely  an  organ  added  to  the  organs  of  the  mo- 
ther, and  assimilating  to  itself  the  juices  it  receives  from  the  uterine  ves- 
sels. It  does  not  hinder  the  other  parts  from  getting  their  nourishment: 
they  all  go  on  living,  and  separating  to  themselves  the  juices  their  exist- 
ence or  their  functions  require.  Haller  ascribes  the  difficulty  with  which 
the  broken  ends  unite,  in  pregnant  women,  to  the  great  quantity  of  earthy 
matter  which  the  foetus  draws  off  from  the  mother.  This  opinion  will 
not  stand;  for,  as  I  have  shown  in  my  preliminary  discourse,  the  phos- 
phate of  lime  has  but  little  to  do  in  the  work  of  re-union,  which  chiefly 
goes  on  by  changes  in  that  part  of  the  bone  which  is  really  organic.  Be- 
sides, this  hypothesis  would  imply  that  consolidation  were  as  difficult  in 
nurses,  whose  milk  carries  off  a  large  quantity  of  phosphate  of  lime.  Yet 
it  has  not  been  observed  that  the  formation  of  callus  is  more  difficult  du- 
ring suckling.  Lastly,  on  this,  as  on  all  occasions,  experience  is  more 
effectual  than  reasoning  ;  now,  experience  shows,  that  the  time  required 
for  the  formation  of  callus,  in  pregnant  women,  is  not  sensibly  longer  than 
in  their  ordinary  state. 

Meanwhile,  the  uterus,  imbued  with  prolific  fluid,  swells,  to  avail  my- 
self of  the  expression  of  a  modern,  like  a  lip  stung  by  a  bee :  it  becomes 
a  centre  of  fluxion  towards  which  the  humours  tend  from  all  quarters. 
The  diameter  of  its  vessels  increases  with  the  thickness  of  its  parietes  : 
these  soften,  and  their  muscular  nature  becomes  more  markedf.  Till 
the  end  of  the  third  month,  the  only  appearance  of  pregnancy  is  in  the 
suspension  of  menstruation  :  the  uterus,  ©f  which  the  cervix  has  yet  un- 
dergone no  change,  has  concentrated  itself  behind  the  pubis,  but  very 
soon  it  rises  above  the  upper  outlet  of  the  pelvis,  pushing  upwards  the 
intestines  and  the  rest  of  the  abdominal  viscera.  Towards  the  end  of 
pregnancy,  it  rises  above  the  umbilicus,  its  fundus  comes  in  contact  with 
the  arch  of  the  colon,  and  reaches  sometimes  to  the  epigastric  region. 
The  compression  it  exerts  on  the  organs  of  digestion,  explains  the  loath- 
ings, and  the  nausea  which  belong  to  the  state  of  pregnancy.  The  de- 
rangement of  sensibility,  by  the  affection  of  the  great  sympathetic^,  ac- 
counts equally  for  those  depraved  tastes,  those  fantastic  appetites,  which 

*  Lecons  de  M.  Boycr,  svir  les  Maladies  des  Os,  refugees  en  un  Traite  coir.plet  cle  ces 
Maladies,  par  A.  Richerand,  2  vols.  8vo. 

j-  According  to  M.  Lobstein,  the  uterus,  during1  pregnancy,  is  ixnalagotis  to  an  organ 
in  a  state  of  chronic  inflammation. 


'     399 

the  ignorant  think  it  so  important  to  gratify.  When  the  term  of  preg- 
nancy draws  near,  respiration  is  oppressed,  the  diaphragm  forced  upward 
by  the  abdominal  viscera,  descends  with  difficulty;  accordingly,  Nature 
has,  as  much  as  possible,  delayed  this  moment  of  oppression,  by  giving 
the  lower  part  of  the  abdomen  a  great  capacity,  at  the  expense  of  the 
chest,  which,  in  women,  is  much  shorter  than  in  men. 

If  the  growth  of  the  foetus,  its  size,  the  quantity  of  liquor  amnii,  the 
developement  of  the  uterus,  were  always  the  same,  we  might  settle  the 
height  to  which  this  last  organ  must  rise,  at  each  stage  qf  pregnancy; 
but  these  conditions  vary  so  much,  in  every  individual,  that  the  terms  one 
might  assign  would  suit  but  a  small  number:  let  it  suffice  to  have  spoken 
of  the  extremes.  The  uterus  tends  to  rise  directly  upwards:  while  en- 
closed within  the  pelvis,  it  preserves  this  direction  ;  but  as  soon  as  it  has 
passed  the  upper  outlet  of  the  pelvis,  it  is  no  longer  supported,  and  in- 
clines forwards,  backwards,  or  to  the  sides.  These  inclinations,  if  they 
go  a  certain  length,  constitute  those  vices  of  situation  which  accoucheurs 
call  obliquities  of  the  uterus-  Their  direction  is  determined  by  the  dis- 
position of  the  parts:  accordingly,  they  almost  always  lie  forwards; 
either  because  the  upper  outlet  of  the  pelvis  is  naturally  so  inclined,  and 
forms,  with  the  horizon,  an  angle  of  45  degrees,  or  because  the  lumbar 
column,  being  convex,  pushes  the  uterus,  which  cannot  depress  it,  upon 
the  anterior  parietes,  which  yields  the  easier,  the  more  frequent  preg- 
nancy has  been. 

The  dilatation  of  the  uterus  is  not  the  effect  of  a  simple  distension  of 
its  parietes,  since  these,  far  from  stretching  thinner,  as  the  viscus  grows 
in  size,  thicken  progressively,  on  the  contrary,  by  the  dilitation  of  ves- 
sels of  all  sorts  and  the  afflux  of  humours.  In  this  sort  of  vegetation,  the 
uterus  is  really  active,  and  does  not  give  way  to  any  efforts  of  the  foetus. 
The  cervix  of  this  viscus,  which,  from  its  greater  consistency,  had  at 
first  resisted  dilatation,  ends  by  yielding  to  the  efforts  of  the  fibres  of  the 
fundus,  on  the  edges  of  the  os  tincae  ;  the  edges  of  that  opening  are 
attenuated,  the  cervix  effaced,  the  orifice  enlarged,  and  you  may  feel 
through  its  parietes,  the  foetus  plunged  in  the  waters  which  its  mem- 
branes contain. 

Towards  the  term  of  gestation,  the  discharge  of  urine  is  more  frequent, 
because  the  bladder,  under  compression,  cannot  contain  it  in  any  quan- 
tity; the  lower  extremities  are  oedematous  ;  the  veins  of  the  legs  vari- 
cose; women  are  also  more  exposed  to  haemorrhoids;  and  these  effects 
depend  on  the.  compression  of  the  vessels,  which  bring  back  the  blood  and 
the  lymph  of  the  inferior  parts,  as  the  cramps,  to  which  pregnant  wo- 
men are  subject,  depend  on  that  of  the  sacral  nerves.  The  groins  are 
alike  painful,  and  there  are  felt  in  them,  twitchings  which  must  be  as- 
cribed to  congestion  in  the  round  ligaments  of  the  uterus*.  Lastly,  the 
skin  of  the  anterior  parietes  of  the  lower  part  of  the  abdomen,  distended 
beyond  measure,  cracks,  when  that  of  the  neighbouring  parts  has  yielded 
as  much  as  it  could. 

Before  explaining  how  the  uterus  expels  the  foetus  and  its  coverings,  at 

*  These  ligaments,  as  well  as  the  uterus,  manifest,  during-  grstation,  their  muscular 
character:  their  vessels  enlarge,  and  their  iibres  become  more  apparent,  according  to 
the  observations  of  M.  Jules  Cloquet,  made  on  the  bodies  of  s  everal  females  who  had 
died  soon  after  child-birth. 

See  the  Note  (I  I.)  last  referred  to,  in  the  APPENDIX,  for  the  changes  which  the  nerves 
of  the  ute-us  and  its  appendages  undergo  during  pregnancy.— Copland. 


400 

the  term  of  gestation,  let  us  consider,  a  little,  this  fruit  of  conception ; 
let  us  study  its  developement,  let  us  examine  the  nature  of  the  relations 
which  it  holds  with  its  mother. 

CCVIII.  History  of  the  fcetus  and  its  coverings.  The  interior  of  the 
uterus,  for  a  short  period  after  the  instant  of  conception,  shows  nothing 
that  leads  to  a  knowledge  of  the  existence  of  its  product.  But,  at  the  end 
of  a  few  days,  there  appears  a  membranous  transparent  vesicle,  filled  with 
a  liquid  trembling  jelly  5  discovering  no  trace  of  organization  and  life. 
But  the  little  ovum  begins  to  grow,  parts  of  the  gelatinous  fluid  assume 
more  consistence,  losing,  at  the  same  time,  their  transparency  :  one  may 
then  distinguish  the  first  rudiments  of  parts,  an  imperfect  appearance  of 
the  head,  trunk,  and  limbs.  The  small  ovum,  free  at  first  in  the  cavity 
of  the  uterus,  contracts  adhesion  to  this  viscus:  its  whole  exterior  sur- 
face becomes  shaggy,  and  this  sort  of  vegetation  is  no  where  more  mark- 
ed, than  in  the  situation  to  be  occupied  by  the  placenta.  Meantime,  to- 
wards the  seventeenth  day,  the  p!arts  which  showed  merely  a  homoge- 
neous semi-transparent  mass,  discover  a  more  determinate  structure.  A 
red  point  appears  in  the  spot  of  the  heart,  it  is  the  heart  itself,  distin- 
guishable by  the  pulsations  of  its  cavities,  and  the  motions  of  the  mole- 
cules of  the  red  liquid  that  fills  them.  Because  the  heart  is  the  punctum 
baliens,  it  is  not  therefore  to  be  concluded  that  it  is  \X\tprimum  vivens.  All 
our  parts  are  formed  together,  all  are  coeval,  as  Charles  Bonnet  has  said; 
only  they  discover  themselves  earlier  or  later  to  the  eye  of  the  observer, 
according  as  the  nature  of  their  organization  is  adapted  to  the  reflection 
of  light*.  Were  we  to  admit  a  successive  order  in  the  formation  of  our 
organs,  the  brain  and  the  nervous  system  might  exist  before  the  heart, 
without  being  perceptible  from  their  transparency. 

Meanwhile,  red  lines,  setting  oft'  from  the  heart,  sketch  the  course  of 
larger  vessels,  and  seem  agitatated  by  the  action  of  these  tubes,  whose 
parieties  are  still  semi-transparent.  As  the  blood,  or  rather  its  red  part, 
extends  from  the  centre  to  the  circumference,  the  forms  become  more 
determinate,  the  parts  unfold  and  grow  rapidly :  points  quite  opaque,  are 
seen,  and  the  form  of  the  foetus  may  be  distinguished.  Bent  upon  itself, 
the  foetus  is  not  unlike  a  French  bean,  suspended  by  the  umbilical  cord, 
which,  as  I  shall  mention  by  and  by,  formed  with  the  foetus  and  its  co- 
verings, proceeds  in  growth  with  them:  it  swims  amidst  the  liquor  amnii, 
cnanges  its  position  the  more  easily,  as  the  space,  in  which  itis  enclosed, 
is  greater,  compared  to  its  size.  As  it  grows,  it  stretches  out  a  little, 
without  ceasing,  however,  to  retain  hs  bent  posture  CLXV1:)  the  head 
composes  the  greater  part  of  its  body  :  the  upper  limbs,  like  little  buds, 
pullulate  first,  then  the  lower  limbs:  the  feet  and  the  hands  appear  im- 
mediately attached  to  the  trunk :  the  fingers  and  toes  show  themselves 
like  little  papillae.  Of  all  the  organs  of  sense,  the  eyes  are  the  first  ap- 
parent: they  are  discernible,  as  two  little  black  spots,  by  the  end  of  the 
first  month ;  the  eyelids  are  produced  and  cover  them.  The  mouth,  at  first 
gaping,  closes  by  the  drawing  together  of  the  lips,  towards  the  end  of 
the  third  month.  During  the  fourth,  a  reddish  coloured  fat  begins  to  be 
disposed  in  the  cells  of  the  mucous  tissue,  ancbthe  muscles  already  exert 
some  action.  The  growth  is  ever  more  rapid,  as  the  foetus  draws  nearer 
to  its  birth.  It  is  impossible  to  assign  the  weight  and  the  length  of  the 

*  The  opinion  of  Bonnet  alluded  to  above,  rests  on  no  observation  that  can  even  lend 
it  a  collateral  support.  We  have  every  reason,  on  the  contrary,  to  infer,  that  a  succes- 
sive order  in  the  formation  of  our  organs  is  observed.  See  some  remarks  on  this  subject 
ui  the  ArrusDii'.  Note  1 1. 


401 

foetus,  at  the  different  stages  of  pregnancy,  since  the  time  of  conception 
is  never  very  certain,  and  further,  the  progress  of  growth  varying  much, 
one  foetus  at  six  months  shall  be  as  large  as  another  at  the  full  term.  Ne- 
vertheless, at  the  time  of  birth,  the  body  is  commonly  eighteen  inches 
long,  and  weighs  from  seven  to  eight  pounds. 

The  secretion  of  bile,  like  that  of  the  fat,  seems  to  begin,  towards  the 
middle  of  gestation,  and  tinges  the  meconium  yellow,  a  mucus  previously 
colourless,  which  fills  the  digestive  tube;  a  little  while  after,  the  hairs 
grow,  the  nails  are  formed  about  the  sixth  or  seventh  month  ;  a  very  thin 
membrane,  which  closed  the  pupil,  tears,  by  what  mechanism  is  unknown, 
and  the  pupil  is  seen.  The  kidneys,  at  first  manifold,  that  is  to  say, 
formed  each  of  from  17  to  18  separate  glandular  lobules,  unite,  and  form, 
on  each  side,  a  single  viscus.  Lastly,  the  testicles,  placed  at  first,  at  the 
side  of  the  lumbar  column,  and  aorta,  near  the  origin  of  the  spermatic 
arteries  and  veins,  then  carried  along  the  iliac  vessels  to  the  inguinal  rings, 
directed  by  the  cellular  cord,  (which  Hunter  calls  the  gubernaculum  testis,) 
clear  this  opening,  carrying  along  with  them  the  portion  of  the  perito- 
neum which  is  to  form  their  tunica  vaginalis,  and  the  inferior  fibres  of 
the  smaller  oblique  muscle. 

This  covering  of  the  testicles,  furnished  by  the  peritoneum,  not  only 
covers  these  organs,  and  is  reflected  again  over  them,  but  also  rises,  in 
adults,  about  half  an  inch  high,  along  the  lower  part  of  the  spermatic  cord. 
If  it  do  not  reach,  it  is  said,  to  the  inguinal  ring,  it  is  because  the  whole 
portion  which,  after  birth,  extended  from  this  opening  to  near  the  testicle, 
has  been  decomposed,  and  is  reduced  to  cellular  tissue.  Upon  reflecting 
on  the  causes  of  the  spontaneous  decomposition  of  a  portion  of  this  perito- 
neal prolongation,  it  occurred  to  me,  that  nothing  was  less  proved,  or  more 
improbable;  in  fact,  in  earliest  life,  the  testicles,  which  have  passed  out 
from  the  abdomen,  by  the  inguinal  rings,  are  very  little  removed  from  this 
opening.  The  portion  of  tunica  vaginalis,  which  is  carried  on  upon  the 
cord  of  the  spermatic  vessels,  rises  up  to  the  rings,  and  even  extends  be- 
yond ;  communicating  with  the  peritoneum,  as  is  sometimes  seen  in  con- 
genital bubonocele.  It  is  only  in  the  progress  of  life,  that  the  testicles 
descend  into  the  scrotum,  still  departing  from  the  opening  which  gave 
them  passage ;  so  that,  in  adults,  the  prolongation,  which  at  first  covered 
the  whole  cord,  which,  just  after  birth,  was  not  more  than  a  few  lines 
long,  is  found  to  cover  only  its  lower  part,  when  it  is  lengthened  some 
inches,  without  any  necessity  of  decomposition;  a  phenomenon,  which 
it  is  as  as  difficult  to  conceive  as  to  explain.  This  opinion,  suggested, 
for  the  first  time,  in  the  first  edition  of  his  works,  is  now  almost  univer- 
sally received. 

CCIX.  Of  the.  circulation  in  the  foetus.  The  principal  difference  that 
is  found  between  the  foetus  and  the  new-born  child,  besides  the  inactivity 
of  the  senses,  and  the  repose  of  the  muscles  subject  to  volition,  lies  in  the 
manner  in  which  the  circulation  is  carried  on.  Too  feeble  to  assimilate 
to  its  own  substance  foreign  substances,  the  foetus  receives  from  its  mo- 
ther, aliments  ready  prepared.  The  arteries  of  the  uterus  receive  a  large 
supply  of  blood  :  this  is  not  all  employed  for  the  nourishment  of  the  or- 
gan itself,  but  passes,  in  great  part,  from  the  mother  to  the  child,  being 
poured,  by  the  uterine  vessels,  into  the  cell  of  a  spongy  substance,  ad- 
hering on  one  side  to  the  uterus,  and  on  the  other  to  the  ovum  which 
contains  the  foetus. 

This  cellulo-vascular  body,  known  under  the  name  of  placenta,  is,  as 

-s  r. 


well  as  the  coverings  of  the  foetus  and  the  foetus  itself,  a  product  of  the 
act  of  generation.  Though  it  adheres  commonly  to  the  fundus  of  the 
uterus,  it  may  adhere  to  any  other  point  of  its  parietes;  sometimes,  jeven, 
it  is  placed  on  its  orifice,  a  circumstance  which  always  makes  delivery 
difficult.  The  side  by  which  it  is  united  to  the  internal  face  of  the  uterus, 
is  uneven,  covered  with  mamillary  projections  (cotyledons^)  which  are 
sunk  in  corresponding  ceils  of  the  parietes  of  the  uterus,  the  internal 
surface  of  which,  loses,  as  it  developes  itself,  the  smoothness  which  it 
had  while  empty,  as  it  is  furrowed  with  depressions  destined  to  receive 
theplacenta,  and  studded  with  projections  which  penetrate  into  the  cells 
of  the  latter. 

The  uterine  arteries,  and  perhaps  likewise  the  absorbents  which  are  so 
large  and  numerous  in  the  gravid  uterus, that  Cruickshank,who  succeeded 
in  injecting  them,  compares  them  to  quills,  thrown  out,  on  the  surface  of 
the  placenta,  and  within  its  spongy  tissue,  the  arterial  blood  of  the  mo- 
ther; according  to  some,  these  vessels  exhale  only  the  serous  part  of  the 
blood,  and  according  te  others,  a  chylous,  lymphatic,  whitish,  or  milky 
substance*.  These  fluids,  effused  within  the  cells  of  the  placenta,  are 
absorbed  by  the  numerous  minute  divisions  of  the  umbilical  vein,  which 
by  thier  union  form  the  trunk  of  this  vessel. 

The  umbilical  vein,  arising  from  the  interior  of  the  placenta,  by  nu- 
merous branches,  detaches  itself  from  it,  and  goes  towards  the  umbilicus 
of  the  child,  enters  his  body,  at  that  aperture,  ascends,  in  a  fold  of  the 
peritoneum,  behind  the  recti  muscles,  to  the  anterior  extremity  of  the 
sulcus  of  the  liver,  goes  along  the  anterior  of  this  fissure,  sending  a  num- 
ber of  branches  to  the  lobes  of  that  viscus,  especially  to  the  left  lobe. 
On  reaching  the  right  extremity  of  the  transverse  fissure,  where  this  last 
meets  the  anterio-posterior,  it  unites,  in  part,  with  the  sinus  of  the  vena 
portse  hepatica,  while  .the  remainder  of  the  vessel,  called  ductus  venosus, 


*  A  German  physician,  SCHKEGER  has  suggested  a  very  ingenious  opinion  on  the  mode 
of  circulation,  between  the  mother  and  child.  He  believes  that  the  uterine  arteries 
pour  out  nothing  but  serum,  into  the  cells  of  the  placenta.  This  serum  is  absorbed  by 
the  lymphatics,  whose  existence 'he  infers  from  analogy,  in  this  organ  and  in  the  um- 
bilical cord,  in  which,  however,  no  one  has  yet  succeeded  in  injecting  them.  These 
vessels  convey  it  to  the  thoracic  duct,  \Vhence  it  is  poured  into  the  left  subclavian  vein, 
and  at -last,  reaches  the  heart,  which  sends  it  along  the  aorta.  It  returns  to  the  placenta 
by  the  umbilical  arteries,  after  being  converted  into  blood,  by  the  actions  of  the  organs 
of  the  foetus.  This  serosity,  after  undergoing  the  process  of  sanguification,  returns 
to  the  foetus  by  the  umbilical  vein,  and  following  the  well-known  course  of  the  foetal 
circulation,  is  subservient  to  the  nourishment  of  its  organs.  The  branches  of  the  um- 
bilical arteries  and  veins,  ramified  in  the  placenta  and  communicating  together  in  this 
spongy  tissue,  reject  through  their  lateral  pores  that  which  can  rto  longer  serve  to  the 
maintenance  of  the  foetus.  This  residue  of  nutrition,  deposited  in  the  cells  of  the  pla- 
centa, is  absorbed  by  the  lymphatics  of  the  uterus,  which  carry  it  back  into  the  mass  of 
the  fluids  of  the  mother.  Not  to  mention  the  impossibility  of  demonstrating  the  pre- 
sence of  the  lymphatics,  in  the  placenta,  or  in  the  umbilical  cord,  Schreger's  hypothesis 
ia  attended  with  two  objections.  How  does  the  nutritious  fluid,  coming  from  the  mo- 
ther and  se  \  along  the  aorta  of  the  fcetus  to  every  part  of  its  body,  return  to  the  pla- 
centa, to  be  brought  back  again  by  the  umbilical  vein  ?  Absorption  scarcely  goes  on  in 
the  foetus;  the  unctuous  substance  with  which  the  body  of  the  fcetus  is  covered,  pre- 
vents that  function  from  taking  place  on  the  surface  of  the  body.  It  goes  on  with  very 
little  more  activity,  within  the  body:  the  excrementitious  secretions  scarcely  exist  before 
birth ;  whatever  is  conveyed  to  the  foetus  is  employed  in  the  developcment  of  its  or- 
gans ;  hence  its  growth  is  so  rapid. — Author's  Note. 

See  the  remark  on  the  function  of  the*  placenta  in  the  Note  (Note  II.)  in  the  AP- 


403 

follows  the  original  direction,  and  opens  into  the  ascending-  or  interior 
vena  cava,  very  near  to  the  spot  where  this  vein  pours  its  contents  into 
the  right  auricle  of  the  hearfc 

CCX.  The  arterial  blood  which  flows  along  the  umbilical  vein,  acquires 
the  properties  of  venous  blood,  and  combines  with  hydrogen  and  carbon, 
and  parts  with  its  vivifying  qualities,  in  flowing  along  the  vessels  of  the 
mother  and  the  tortuous  vessels  of  the  placenta.  It  parts  with  these 
principles,  and  again  becomes  vivified*  by  circulating  through  the  liver, 
which,  at  this  period  of  life^  fulfils  the  function  which, after  birth,  is  com- 
mitted to  the  lungs.  Hence  the  liver  and  brain  form  the  greatest  part  of 
the  weight  of  a  new  born  child.  The  former  alone  occupies  the  greatest 
part  of  the  abdomen.  It  acquires  this  bulk,  by  assimilating  to  itself  the 
hydrogen  and  carbon  of  the  umbilical  blood.  Its  substance  is  adipose, 
oily^  and  contains  these  two  principles,  in  a  considerable  proportion. 
The  secretion  of  the  bile  and  that  of  the  fat,  the  only  secretions  that  are 
manifestly  carried  on  in  the  foetus,  may  besides  supply,  very  well,  the 
want  of  respiration*. 

The  blood  conveyed  by  the  umbilical  vein  into  the  lower  vena  cava,  and 
deposited  by  that  vein  into  the  right  auricle,  does  not  unite  with  that 
which  is  brought  by  the  descending  cava,  from  the  upper  parts,  for  as 
was  observed  elsewhere,  the  orifices  of  these  two  vessels  not  being  di- 
rectly opposed  to  each  other,  the  columns  of  blood  which  flow  in  them  do 
not  meet  each  other.  That  which  is  brought  by  the  lower  cava,  passes 
through  the  foramen  ovale,  towards  which  the  mouth  of  that  vessel  is 
turned;  it  passes  into  the  left  auricle,  thence  into  the  left  ventricle,  with- 
out circulating  through  the  lungs,  which  containing  no  air  and  being  dense 
and  indurated,  could  not  have  received  it ;  the  contractions  of  the  left 
ventricle  send  it  into  the  aorta,  the  force  of  its  impetus  is  broken,  by 
striking  against  the  great  arch  of  this  artery.  It  enters  into  the  vessels 
which  arise  from  it,  and  these  convey  it  directly  to  the  brain  and  upper 
parts.  This  blood  is  the  most  pure,  the  most  oxygenated,  and  that  which 
comes  most  immediately  from  the  placenta  ;  it  has  not  yet  circulated  in 
the  body  of  the  foetus,  with  the  exception  of  a  very  small  quantity  brought 
from  the  pelvis  and  lower  parts,  for,  the  blood  which  comes  from  the 
abdominal  viscera,  is  purified  in  passing  through  the  liver.  The  other 
parts  of  the  body  receive,  on  the  contrary,  blood  very  imperfectly  oxy- 
genated, since  the  very  inconsiderable  quantity  which  the  contractions 
of  the  left  ventricle  of  the  aorta  have  not  been  able  to  send  into  the  ves- 
sels arising  from  the  arch  of  this  vessel,  mixes  with  the  venous  blood 
which  is  brought  by  the  ductus  arteriosus,  immediately  below  this  cur- 
vature. Hence  the  growth,  which  is  always  relative,  not  only  in  respect 
to  the  quantity,  but  likewise  to  the  vivifying  qualities  of  arterial  blood, 
is  much  more  rapid,  before  birth,  in  the  upper  parts,  so  that  the  brain 
alone  constitutes  the  greatest  part  of  the  body,  and  the  shoulders,  the 
chest,  and  the  upper  extremities,  are  developed,  in  a  much  greater  de- 
gree than  the  abdomen,  and  especially  than  the  pelvis  and  lower  extre- 
mities. 

The  blood  which  is  brought  by  the  descending  cava,  from  the  upper 
parts  of  the  body  of  the  foetus,  passes  into  the  right  ventricle  which  forces 
it  into  the  pulmonary  artery ;  this  vessel  sends  only  two  small  branches  to 
the  lungs,  and  terminates,  by  a  vessel  called  the  ductus  arteriosus,  into 


*  See  APPENDIX,  Note  1 1, 


404 

the  aorta,  immediately  below  the  origin  of  the  left  subclavian  arterr.  The 
aorta,  at  its  origin,  is  therefore  filled  with  arterial  blood,  sent  towards 
the  upper  parts  of  the  body,  by  the  contraction  of  the  left  ventricle,  while 
the  remainder  of  this  artery  contains  venous  blood,  which  is  expelled  by 
the  combined  action  of  both  ventricles. 

It  is  impossible,  in  this  arrangement,  not  to  recognize  an  evident  design. 
In  fact,  if  the  whole  force  of  the  heart  had  been  exerted  to  send  the  blood 
towards  the  brain,  the  delicate  texture  of  this  viscus  would  have  been 
injured  by  it ;  the  combined  action  of  the  two  ventricles  was,  on  the  con- 
trary,.required,  to  enable  the  blood  to  circulate,  along  the  extensive  and 
tortuous  channels  of  the  umbilical  cord  and  placenta.  The  aorta,  on 
reaching  the  body  of  the  fourth  or  fifth  lumbar  vertebra,  divides  into  the 
two  umbilical  arteries;  these  send  to  the  pelvis  and  to  the  lower  parts, 
only  very  insignificant  branches,  which  convey  blood  that  contains  a  very 
small  quantity  of  oxygen ;  they  then  bend  along  the  sides  of  the  bladder, 
incline  inwards,  approach  towards  the  urachus,  pass  out  of  the  abdomen, 
at  the  umbilicus,  and  -joining  the  umbilical  vein  which  had  entered, 
through  the  same  opening,  into  the  body  of  the  foetus,  form  with  it  the 
umbiiiral  cord. 

CCXI.  The  length  of  the  umbilical  cord,  measured  from  the  umbili- 
cus to  the  placenta,  is  from  twenty  to  twenty-four  inches.  It  may  be  not 
above  six  inches  long,  or  may  greatly  exceed  that  length,  as  is  proved  by 
a  case  of  M.  Baudelocque,  in  which  the  umbilical  cord  was  fifty-seven 
inches  in  length,  and  passed  seven  times  round  the  child's  neck;  which 
circumstance,  by  the  way,  shows  that  the  foetus  moves  in  its  mother's 
womb.  Of  the  three  vessels  which  form  the  umbilical  cord,  two,  which 
are  the  smallest,  have  an  arterial  structure,  though  they  convey  blood 
that  is  truly  venous,  while  the  umbilical  vein  carries  arterial  blood  to  the 
foetus.  The  umbilical  arteries,  on  reaching  the  placenta,  divide,  and  are 
lost  in  its  substance,  in  a  multitude  of  vessels  whose  extremities  deposit, 
into  the  areolae  of  its  tissue,  the  blood  coming  from  the  foetus,  and  which 
is  to  be  returned  to  the  mother.  Does  the  course  of  injection,  from  the 
umbilical  vein  into  the  arteries,  prove  that  there  exists  an  anastomosis 
between  the  extremities  of  these  vessels  ? 

The  foetus  is  connected  to  the  mother,  by  the  umbilical  cord  and  placen- 
ta ;  the  veins,  or  the  lymphatics  of  the  uteras,  and  perhaps  both  these 
sets  of  vessels,  take  up,  in  the  spongy  tissue  of  the  placenta,  the  blood 
that  has  been  employed  In  the  nutrition  of  the  foetus,  and  return  it  to  the 
mother,  that,  after  undergoing  a  change  by  the  action  of  her  organs,  and 
especially  by  that  of  the  atmospherical  air,  by  means  of  the  pulmonary 
circulation,  it  may  become  fit  for  the  nourishment  of  the  foetus.  Whether 
we  inject  the  uterine  vessels,  or  whether  we  force  the  wax  along  the  um- 
bilical vein,  it  never  fills  but  a  part  of  the  placenta,  which  has  led  to  the 
division  of  this  substance  into  two  parts,  the  one  belonging  to  the  mother, 
which  has  been  called  uterine,  the  other,  called  the  foetal  portion,  which 
forms  a  part  of  the  umbilical  cord. 

The  vessels  of  the  mother  do  not,  therefore,  anastomose  with  those  of 
the  fretus  within  the  placenta,  the  circulation  is  not  continued  from  the 
one  to  the  other.  If  the  communication  were  immediate,  the  beats  of 
the  pulse  of  the  child  ought  to  be  simultaneous  with  those  of  the  mother, 
whereas  they  are  much  more  frequent,  as  may  be  observed,  at  the  time 
of  birth,  before  the  division  of  the  umbilical  cord.  If  the  veins  of  a  bitch, 
ready  to  whelp,  arc  opened,  the  animal  dies  of  hemorrhage,  and  her  body 


405 

remains  bloodless.  The  placenta,  however,  is  empty,  only  in  the  part 
that  adheres  to  the  uterus,  the  rest  of  the  placenta,  as  well  as  the  foetus, 
are  filled  with  blood,  as  usual.  It  is  obvious,  that  if  the  vessels  of  the 
uterus  had  been  directly  continuous  with  those  of  the  placenta,  delivery 
would  not  have  taken  place,  without  their  being  torn,  alarming  hemorr- 
hage, inflammation,  and  even  suppuration  of  the  uterus  would  have  been 
the  consequence.  Lastly,  the  force  with  which  the  heart  and  arteries  of 
the  mother  impel  the  blood  along  her  vessels,  would  have  been  attended 
with  danger  to  the  organs  of  the  foetus,  which  are  too  soft  to  sustain, 
without  injury,  so  violent  a  shock.  Though  the  placenta  and  the  umbili- 
cal cord  form  the  bond  of  union  between  the  foetus  and  the  mother,  it 
must  be  confessed,  that  they  belong  chiefly  to  the  former,  and  may  be 
considered  as  a  continuation  of  its  body. 

-  CCXIL  The  existence  of  the  foetus  is  solely  vegetative;  he  is  continu- 
ally drawing  from  the  juices,  which  the  vessels  of  the  mother  send  to  the 
placenta,  what  is  to  serve  to  his  nourishment  and  growth.  He  may  be 
considered  as  a  new  organ,  the  product  of  conception,  participating  in 
general  life,  but  having  a  peculiar  life,  and  to  a  certain  degree,  independ- 
ent of  that  of  the  mother.  Bent  on  himself,  so  as  to  occupy  the  least 
possible  space,  he  cannot  be  considered  as  asleep ;  for  not  only  are  the 
organs  of  sense  and  of  motion  in  a  perfectly  quiescent  state,  but,  besides, 
several  of  the  functions  of  assimilation  are  inactive,  as  digestion,  respira- 
tion, and  most  of  the  secretions.  The  foetus  performs,  in  the  midst  of 
the  liquor  amnii,  spontaneous  motions  which  accoucheurs  reckon  among 
the  signs  of  pregnancy.  The  existence  of  these  phenomena  has  been  de- 
nied, and  the  displacement  of  the  foetus  has  been  ascribed  to  a  mere 
shaking  of  the  body:  this  was  asserted  on  the  ground  of  the  intimate 
connexion  between  respiration  and  muscular  motion.  It  was  said,  that 
the  blood  of  the  foetus,  not  being  impregnated  with  oxygen,  in  its  passage 
through  the  lungs,  contractility  would  not  exist.  But  besides,  that  a  fact 
may  be  certain,  without  being  easily  explained,  it  may  be  answered,  that 
the  mother  fulfils  this  office  for  the  foetus,  and  sends  it  arterial  blood,  fit- 
ted to  maintain  the  contractility  of  the  muscles. 

As  we  perform  no  motion,  but  in  virtue  of  impressions  previously  re- 
ceived, and  as  the  organs  of  sense,  in  the  foetus,  are  completely  inactive, 
it  is  not  easy  to  say,  why  it  should  move  in  the  womb.  The  touch,  how- 
ever, is  exerted,  when  any  part  of  the  surface  of  the  body  of  the  foetus 
comes  in  contact  with  the  internal  part  of  the  cavity  in  which  it  is  con- 
tained. Lastly,  the  internal  impressions  experienced  by  the  great  sym- 
pathetics,  may  act  as  an  occasional  cause  of  such  motions. 

The  foetus  is  nourished,  like  every  other  organ,  by  appropriating  to  it- 
self, whatever  is  suited  to  its  nature,  in  the  blood  brought  to  it,  by  the 
vessels  of  the  uterus.  The  interception  of  this  fluid,  by  a  ligature,  or  by 
compression  of  the  umbilical  cord,  would  occasion  death,  though  not,  as 
has  been  imagined,  by  a  sudden  and  quick  suffocation,  but  the  action  of 
the  organs  would  become  gradually  weakened,  and  at  last  cease,  when 
the  fluids  of  the  foetus,  being  no  longer  vivified  by  the  mixture  of  new 
juices  from  the  mother,  would  be  completely  deprived  of  their  nutritive 
parts.  It  is  now  well  ascertained,  that  the  liquor  amnii  does  not  serve  to 
the  nutrition  of  the  foetus,  whose  mouth  is  closed,  whose  head  is  bent  on 
his  breast,  and  whose  intestinal  canal  is  filled  with  a  fluid  different  from 
that  in  which  the  whole  body  is  immersed.  Besides,*may  not  the  unctu- 
ous substance  with  which  the  surface  of  the  skin  is  covered,  prevent  the 


406 

absorption  which  might  otherwise  take  place,  from  the  outer  part  of  the 
body*? 

It  was  long  believed  that  the  fcetus  was  in  an  upright  position,  during 
the  first  months  of  life,-  but  that,  towards  the  end  of  pregnancy,  it  fell  into- 
a  different  position,  and  lay  with  its  head  downwards.  This  errone- 
ous opinion,  believed  from  its  antiquity,  and  because  it  was  admit- 
ted by  several  physiologists,  is  completely  refuted  in  Professor  Baude- 
locque's  work  on  miduifery.  The  absurdity  of  this  hypothesis  is  mani- 
fest, if  it  be  considered  that  the  head  of  the  embryo,  the  most  bulky  and 
weighty  part  of  the  body,  must  necessarily  occupy  the  most  depending 
part. 

The  plumpness  and  the  strength  of  the  feetus  do  not  altogether  depend 
on  the  strength  of  the  mother.  Corpulent  and  strong  women  often  bring. 
forth  puny  children,  while  others  who  are  thin  and  feeble,  bring  forth 
children  plump  and  healthy.  Such  instances,  however,  are  exceptions  to 
the  general  rule,  as,  cseterisparibus,  the  healthy  state  of  the  foetus  is  to  be 
estimated  by  that  of  the  mother.  The  morbid  condition  of  the  fluids  of 
the  mother  has  a  considerable  influence  on  the  health  of  the  foetus,  and  is 
perhaps  the  way  in  which  hereditary  diseases  are  transmitted,  which,  by 
others,  are  ascribed  to  a  diseased  state  of  the  semen* 

The  fcetus  is  subject  to  affections  of  various  kinds,  whether  of  sponta- 
neous origin,  or  arising  from  a  germ  received  from  the  mother.  Foetus- 
es have  been  seen  with  cicatrices,  which  clearly  showed,  that  solutions  of 
continuity,  of  various  kinds,  had  taken  place.  A  child,  born  with  the  loss- 
of  some  limb,  has  met  with  the  accident,  in  consequence  of  some  affec- 
tion experienced  in  the  womb.  Professor  Chaussier  having  been  called 
in  to  a  case  of  this  kind,  found  the  hand  and  a  portion  of  the  fore-arm, 
among  the  membranes!. 

CCXIII  Of  monsters.  As  it  is  useful  to  study  Nature,  even  in  her  ir- 
regularities, I  shall  say  a  few  words  on  the  subject  of  monsters,  adopting 
the  arrangement  proposed  by  Buffon,  of  dividing  them  into  three  classes: 
the  first  including  monsters  from  excess  ;  the  second,  monsters  from  de- 
fect ;  the  third  including  those  in  which  there  is  a  misplacement  of  or- 
gans. In  the  first,  are  included  those  which  have  superaumerary  limbs 
or  figures,  or  even  two  bodies  joined  in  various  ways.  In  the  second, 
children  born  with  a  hare-lip,  or  who  are  deficient  in  some  one  part.  In 
the  last  place,  those  monsters  belong  to  the  third  class,  in  which  there  is 
a  general  transposition  of  organs  ;  when,  for  example,  the  heart,  the 
spleen,  and  the  sigmoid  flexure  of  the  colon  are  on  the  right  side,  and  the 
liver  and  caecum  on  the  left ;  those  born  with  herniae  of  different  kinds, 
likewise  belong  to  this  class.  One  may  reckon  among  these  monstrous 
confirmations,  spots  in  the  skin,  the  colour  of  which  always  resembles 
that  of  some  of  our  fluids,  but  whose  various  forms  are  purely  accident- 
al, though,  from  prejudice,  one  is  apt  to  imagine  some  likeness  to  objects 
longed  for  by  pregnant  women  accustomed  to  those  fantastic  appetites 
and  longings,  so  frequent  during  pregnancy. 

Various  attempts  have  been  made  to  account  for  these  unnatural  forma- 


*  May  not  also  this  substance,  which  is  the  produce  of  the  small  sebaceous  glands  of 
the  skin,  prevent  the  cuticle  from  being'macerated  in  the  surrounding  fluid,  owing  to  its 
being1  repulsive  of  water,  and  to  its  being  retained  closely  applied  to  the  cuticle  by  the 
fine  downy  hair,  or  pubescence,  which  thinly  covers  the  skin  during  the  early  periods 
of  existence. —  Copland. 

f  See  the  APPENDIX,  Note  1 1. 


tiotis :  some,  as  Mallebranche,  attributed  them  to  the  'influence  of  the 
mother's  imagination  on  the  foetus  in  the  womb ;  others,  as  Maupertuis, 
thought  that  her  passions  communicated  to  her  humours  irregular  mo- 
tions, which,  acting  with  violence  on  the  delicate  body  of  the  embryo, 
disturbed  its  structure.  Disease,  while  the  child  is  in  utero,  is  a  much 
more  probable  cause  of  such  affections. 

If  the  two  foetuses,  contained  in  one  ovum,  lie  back  to  back,  and  if  the 
surfaces  at  which  they  are  in  contact,  become  affected  with  inflammation, 
it  is  easy  to  conceive  that  adhesion  may  take  place  beween  them.  By 
placing,  in  a  confined  vessel,  the  fecundated  ova  of  a  tench  or  any  other 
fish*,  the  numourous  young  ones,  which  are  formed,  not  having  space 
sufficient  for  their  growth,  adhere  to  each  other,  and  fishes  truly  mon- 
strous in  their  formation  are  produced. 

When,  from  disease,  or  from  an  original  malformation,  the  body  of 
the  foetus  is  deficient  in  some  of  its  parts,  the  others  are  better  nourish- 
ed and  grow  to  a  large  size.  Hence,  in  acephalous  monsters,  as  there  is 
no  brain,  the  blood  which  should  be  sent  to  that  viscus,  going  to  the  face, 
it  acquires  a  remarkable  enlargement, 

One  of  the  most  curious  of  all  the  cases  of  monstrosities,  depending  on 
an  original  defect  in  the  organization  of  the  germs,  is  that  which  was 
sent  a  few  years  ago,  by  the  Minister  of  the  Interior,  to  the  School  of 
Medicine  at  Paris.  I  shall  give  an  abstract  of  it,  from  a  more  de- 
tailed account,  drawn  up  with  much  accuracy  and  sagacity  by  Mr.  Du- 
puytren. 

A  young  man,  thirteen  years  of  age,  had  complained,  from  his  earliest 
infancy,  of  pain  in  the  left  side  and  lower  part  of  the  abdomen.  This 
side  had  been  prominent  and  contained  a  tumour,  from  the  earliest  peri- 
od of  life.  At  the  age  of  thirteen,  he  was  seized  with  fever,  the  tumour 
increased  in  bulk,  and  became  very  painful.  Some  days  after,  lie  voided, 
by  stool,  purulent  and  fetid  matters  ;  at  the  end  of  three  months,  he  be- 
came wasted  by  marasmus,  he  passed,  by  stool,  a  bail  of  hairs,  and  in  the 
course  of  a  few  weeks,  died  of  consumption. 

On  opening  his  body,  there  was  found,  in  a  cavity  in  contact  with  the 
transverse  arch  of  the  colon,  and  communicating  with  it,  some  balls  of 
hairs  and  an  organized  mass.  The  cyst,  situated  in  the  transverse  meso- 
colon,  near  the  colon,  and  externally  to  the  digestive  canal,  communicated 
with  the  intestine.  But  this  communication  was  recent  and  accidental, 
and  one  could  plainly  see  the  remains  of  the  septum  between  these  cavi- 
ties. The  organized  mass  presented,  in  its  forms,  a  great  number  of  fea- 
tures of  resemblance  with  the  human  foetus,  an'd,  on  dissection,  no  doubt 
could  be  entertained  of  its  nature.  There  was  discovered  in  it,  the  trace 
of  some  of  the  organs  of  sense,  a  brain,  a  spinal  marrow,  very  large  nerves, 
muscles  converted  into  a  sort  of  fibrous  matter,  a  skeleton  consisting  of  a 
vertebral  column,  ahead  and  pelvis,  and  limbs  in  an  imperfect  state; 
lastly,  a  very  short  umbilical  cord  attached  to  the  transverse  mesocolon, 
at  the  outer  part  of  the  intestine,  an  artery  and  vein,  ramifying  at  each  of 
their  extremities,  where  they  were  in  contact  with  the  foetus  and  with 
the  individual  which  contained  it.  This  much  is  sufficient  to  establish 
the  distinct  existence,  as  an  individual,  of  this  organized  mass,  though, 
in  other  respects,  destitute  of  organs  of  digestion,  of  respiration,  of  the  se- 
cretion of  urine,  and  of  generation.  The  absence,  however,  of  a  great  num- 
ber of  the  organs  necessary  to  the  maintenance  of  life,  should  make  it  be 
considered  as  one  of  those  monstrous  f'cettises,  not  destined  to  live  be- 


468 

yond  the  moment  of  birth.  This  foetus  was  evidently  contemporary  with 
the  boy  to  whose  body  it  was  attached.  Similar  to  the  product  of  extra 
nterine  conceptions,  it  received  its  nourishment  from  that  which  may  be 
considered  as  its  brother,  and  whose  germ  had  originally  inclosed  its  own. 
During  the  thirteen  years  of  the  life  of  Bissieu,  (this  was  the  name  of 
the  subject  of  this  singular  case)  the  organized  mass  obtained  from  the 
mesocolon,  by  means  6f  vessels  of  its  own,  the  blood  necessary  for  its  ex- 
istence; this  blood,  propelled  by  the  organs  of  circulation  into  the  body 
of  the  foetus,  returned  afterwards  to  the  mesocolon  of  the  boy  who  had 
so  long  been  to  him  as  a  mother.  /ft  last,  the  period  fixed  by  Nature  for 
expulsion  beig  arrived,  and  this  expulsion  being  impracticable,  the  Cyst 
became  inflamed ;  the  inflammation  extended  to  the  intestine,  the  part 
which  separated  these  two  cavities  was  destroyed,  and  the  cyst  opened 
into  the  colon  5  pus  and  hair  were  voided  by  stool,  and  the  patient  died 
of  marasmus.  The  drawings  of  different  parts  of  the  body  of  this  foetus, 
taken  by  M.  Cuvier  and  M.  Jadelot,  render  this  interesting  case  most 
complete.  They  will  be  published  in  the  first  volume  of  the  transactions 
of  the  Academical  Society,  near  the  Faculty  of  Medicine  at  Paris*. 

We  ought  not  to  be  ready  to  place  implicit  confidence  in  the  extraor- 
dinary stories  contained  in  the  older,  writers,  and  even  in  some  of  the 
moderns.  In  reading  the  periodical  publications  of  the  seventeenth,  and 
even  of  the  eighteenth  century,  one  is  apt  to  wonder  at  the  marvellous 
things  which  they  contain.  Among  other  strange  cases,  is  that  of  a  girl 
that  was  born  with  a  pig's  head  ;  another  of  a  woman  who  was  deliver- 
ed of  an  animal,  in  every  respect,  like  a  pike.  There  was  a  time,  says 
a  philosopher,  when  philosophy  consisted  merely  in  seeing  prodigies  in 
nature. 

CCXIV.  Of  the  coverings  of  the  foetus.  The  name  of  after-birth  is 
given  to  the  envelopes  of  the  fcetus,  because  they  are  not  expelled  from 
the  uterus,  till  after  the  birth  of  the  child.  The  ovoid  sac,  which  con- 
tains the  foetus,  is  formed  by  two  membranes  in  contact  with  each  other. 
The  name  of  chorion  is  given  to  that  which,  by  its  external  and  shaggy 
surface,  adheres  to  the  inside  of  the  uterus,  the  other,  a  concentric  mem- 
brane to  the  former,  but  of  less  thickness,  and  to  be  considered  as  the  se- 
cretory organ  of  the  fluid  which  fills  the  ovum,  is  called  the  amnion. 
The  third  envelope,  admitted  by  Hunter,  and  called  by  that  physiologist, 
the  membrana  decidua,  is  nothing  more  than  the  languinous  tissue  pre- 
sented by  the  external  part  of  the  chorion,  after  tearing  the  multitude  of 
cellular  and  vascular  filaments,  by  means  of  which  the  ovum  adheres  to 
the  uterus.  The  placenta  is  itself  merely  a  thicker  portion  of  nearly  the 
same  tissue,  in  which  the  umbilical  vessels  are  ramified.  The  uterus  is 
also  thicker  at  the  part  which  corresponds  to  the  placenta,  because 
it  is  there  that  the  communication  of  the  fcetus  with  the  mother  is  estab- 
lished*. 


*  Mr.  Young  of  London,  has  communicated  a  case  of  the  same  kind,  in  a  valuable 
paper  inserted  in  the  first  volume  of  the  Medico-Chirurgical  Transactions.  In  Mr. 
Young's  case,  the  foetus  was  contained  in  a  cyst  that  seemed  to  answer  the  purpose  of 
membranes  and  placenta ;  it  was  without  a  brain,  but  had  imperfectly  formed  digestive 
organs  and  external  organs  of  generation. — See  vol.  1st  of  the  Medico "Chirurgical  Trans- 
actions — Trans. 

f  The  membrana  decidua,  a  perfect  epichorion,  as  it  has  been  culled  by  M.  CIIAFSIKU, 
is  the  result  of  the  generative  orgnsm.  It  is  formed  on  tiie  internal  surface  of  the  uterus 


409 

The  liquor  atrinii  is  a  serous  fluid,  of  a  sweetish  odour,  of  insipid  taste, 
rendered  slightly  turbid  by  a  milky  substance  which  it  holds  suspended, 
and  somewhat  heavier  than  distilled  water,  1,004.  It  is  almost  complete- 
ly aqueous;  albumine,  soda,  muriate  of  soda,  and  phosphate  of  lime,  dis- 
covered in  it  by  MM.  Buniva  and  Vauquelin,  forming  only  0,012  of  the 
whole  mass.  It  turns  of  a  green  colour,  tincture  of  violets,  and  reddens 
that  of  turnsol;  a  very  remarkable  circumstance,  as  is  observed  by  the 
last  mentioned  philosophers  and  indicating  the  co-existence  of  an  alkali 
and  of  an  acid  in  a  separate  state.  The  latter  is,  in  so  small  a  quantity, 
so  volatile,  and  so  soluble  in  the  liquor  amnii  of  woman,  that  it  has  never 
yet  been  obtained  by  itself:  there  is  found,  however,  in  the  liquor  amnii 
of  the  cow,  a  peculiar  acid,  called  by  MM.  Buniva  and  Vauquelin  the 
amniotic  acid.  The  liquor  amnii  is  in  greater  quantity,  in  proportion  to 
the  size  of  the  foetus,  according  as  the  latter  is  nearer  the  period  of  its 
formation.  It  is  the  product  of  arterial  exhalation.  Its  materials  are 
supplied  by  the  bljod  conveyed  by  the  vessels  of  the  uterus.  This  is 
proved,  not  merely  by  analogy,  but  likewise  by  observing  the  connection 
between  the  qualities  of  the  liquor  amnii  and  the  regimen  of  the  mother. 
In  a  woman  who  had  used  mercurial  friction,  in  the  course  of  her  preg- 
nancy, the  liquor  amnii  was  observed  to  whiten  copper*. 

The  fundus  of  the  bladder,  in  quadrupeds,  is  continuous  with  a  canal, 
of  which  the  rudiments  are  observed  in  man,  and  which  is  called  the  ura- 
chus.  This  canal  joins  the  umbilical  vessels,  passes  out  with  them  at 
the  umbilicus,  and  terminates  in  a  membranous  sac,  between  the  chori- 
on  and  amnion  ;  it  is  called  the  allantois:  it  is  always  found  in  the  foetus 
of  the. lower  animals,  but  it  is  very  indistinct,  and  often  does  not  exist  in 
man.  Some  anatomists  say  they  have  seen  the  urachus  sri sing  from  the 
human  bladder,  and  which  is  commonly  ligamentous,  terminate  in  a 
small  vesicle,  which  some  of  them  compare  to  a  melon  seed ;  while 
others  say  its  bulk  does  not  exceed  a  millet  or  hemp  seed.  So  small 
a  vesicle  can  certainly  answer  no  purpose;  the  urachus  always  forming 
a  solid  cord,  seldom  pervious,  and  even  of  very  small  bore,  in-  the  part 
nearest  the  fundus  of  the  bladder.  The  existence  of  these  parts  furnishes 
an  additional  proof.of  what  was  stated  in  speaking  of  the  uses  of  the  valve 
of  the  caecum,  viz.  that  there  are  in  the  animal  body,  organs  which  an- 
swer no  purpose,  and'  which  merely  indicates  the  plan  which  Nature  has 
followed  in  the  reproduction  of  beings,  and  the  gradations  which  she  has 
uniformly  observed  in  the  divisions  of  the  speciesf. 

CCXV.  Of  the  natural  term  of  gestation.  The  foetus  may  exist 
without  the  maternal  influence,  when  arrived  at  the  period  of  seven  or 
eight  months  from  the  instant  of  conception.  All  accoucheurs  agree  that 
it  may  be  delivered  alive,  at  this  period,  and  that  it  stays  two  months 
longer  in  the  uterus,  only  that  it  may  gain  more  strength,  and  be  better 
fitted  to  resist  the  new  impressions  which  it  is  to  experience,  on  coming 


from  the  irritation  excited  by  the  act  of  impregnation.  It  serves  to  unite  the  ovum  to 
the  interior  of  the  uterus;  and,  although  the  ovum  may  never  reach  this  viscus,  the  de- 
cidua  is  developed,  notwithstanding,  on  its  internal  surface.  This  circumstance  is  al- 
ways observed  in  extra-uterine  fetation. 

*  M.  Laissaigne  has  discovered  a  gas  composed  of  78,3  of  azote,  and  21,7  of  oxygen 
in  the  liquor  amnii  of  some  inferior  animals.  This  gas  is  respirable  and  supports 
combustion — .See  Archives  de  Medecines,  Juin.  1823. 

t  See  the  APPENDIX,  rfote  1 1. 

3  F 


410 

into  the  world.  A  child,  however,  has  been  known  to  live,  though  born 
at  the  sixth  month  of  pregnancy,  in  premature  labour  ;  but,  in  general, 
the  child  is  the  more  likely  live  when  born  at  the  usual  period ;  that  is, 
towards  the  end  of  the  ninth  solar  month,  or  of  the  tenth  lunar.  It  is  ob- 
served, that  children  born  at  seven  months,  however  robust  they  may 
prove  afterwards,  are  very  feeble  when  born,  have  their  eyes  clos- 
ed, and  are  in  a,  state  of  extreme  debility  and  suffering,  during  the  two 
months  which  they  ought  to  have  spent  in  their  mother's  womb:  this  proves 
how  necessary  it  is  that  gestation  should  be  carried  on  to  the  end  of  the 
ninth  solar  month. 

If  the  foetus  may  live  though  separated  from  its  mother,  before  the 
natural  period,  may  it  not,  likewise,  remain  longer  within  the  womb, 
grow  with  less  rapidity,  and  be  expelled  some  days,  weeks,  and  even 
months  later?  How  difficult,  therefore,  will  it  not  be  to  assign  a  precise 
term,  beyond  which  we  shall  not  be  able  to  admit  the  possibility  of  a  late 
birth ! 

There  are  said  to  be  authentic  cases  of  children  born  more  than  ten 
moths  after  conception ;  yet  the  laws,  which  cannot  be  founded  on  rare 
exceptions,  do  not  allow  of  so  long  a  period  in  deciding  on  the  legiti- 
macy of  children  born  after  the  dissolution  of  matrimony. 

CCVI.  Of  parturition.  When  the  foetus  has  remained  sufficiently 
long  within  its  mother's  womb,  to  acquire  the  degree  of  strength  requir- 
ed for  its  insulated  existence,  it  becomes  separated  from  her  carrying 
along  with  it  the  parts  which  inclosed  it,  and  by  which  it  was  connected 
to  the  uterus.  Its  expulsion  from  the  uterus  is  called  delivery.  The 
most  riduculous  opinions  have  been  entertained,  with  regard  to  -causes 
which  determine  the  coming  on  of  labour:  according  to  some,  Fabricius 
of  Aquapendente,  for  instance,  it  is  the  want  of  fresh  air,  which  makes 
the  foetus  rupture  its  membranes;  according  to  others,  the  foetus  is  de- 
termined to  the  same  process,  by  the  necessity  of  voiding  the  meconium, 
an  excrementUious  fluid,  which  fills  the  intestinal  canal.  It  has  been  said, 
that  the  foetus  was  urged  to  it  by  the  want  of  food,  or  that  labour  de- 
pends on  the  re-action  of  the  fibres  of  the  uterus,  which,  distended  beyond 
measure,  towards  the  end  of  pregnancy,  close  on  themselves,  and  over- 
come the  resistance  of  the  cervix  uteri,  which  is  thinned  and  gradually 
dilated.  But,  if  this  last  hypothesis  be  correct,  and  it  is  the  only  one 
that  is,  at  present,  in  any  esteem,  how  comes  it,  that  in  a  woman,  whose 
uterus  is  of  a  determinate  size,  labour  does  not  come  an,  when  there  are 
twins,  at  the  end  of  four  months  and  a  half,  by  which  period,  the  same 
degree  of  distension  would  be  produced,  as  by  one  child  at  the  full 
time? 

It  is  very  true,  that  for  a  fortnight  and  even  sometimes  for  a  month, 
before  labour,  the  uterus  seems  to  be  preparing  for  the  expulsion  of  the 
fetus.  This,  at  least,  may  be  inferred  from  the  prominence  of  the  cer- 
vix of  the  uterus,  which  may  then,  sometimes,  be  felt  ;  and  which  is 
evidently  produced  by  the  membranes  containing  waters,  which  in- 
sinuate themselves  within  the  orifice  of  the  uterus,  when  this  organ 
contracts,  and  which  collapse  and  recede,  when  the  uterus  is  relaxed. 

The  product  of  conception,  after  a  certain  time,  reaches  a  period  at 
which  it  may  exist,  separated  from  the  mother.  When  this  period  is 
arrived,  the  ovum  in  which  it  is  contained,  detaches  itself  from  the 
uterus,  by  a  mechanism,  in  every  respect,  similar  to  that  by  which  the  stalk 
of  a  ripe  fruit  drops  from  the  bough  on  which  it  hung.  Then  in  all  pro- 


411 

bability,  the  foetus  refuses  to  admit  the  blood  sent  to  it  by  the  umbilical 
vein.  The  placenta  becomes  affected  with  congestion;  the  stagnation  of 
the  fluids  extends,  gradually,  to  the  uterus,  and  to  the  neighbouring 
parts.  Stimulated  by  their  presence,  these  organs  are  called  into  ac- 
tion, the  woman  feels  wandering,  irregular  pains,  similar  to  cholic 
pains,  which  become  more  acute,  are  attended  with  a  feeling  of  con- 
striction, and  act  from  above  downwards,  that  is,  from  the  fundus  to 
the  cervix  of  the  uterus.  This  contractile  cavity,  assisted  by  the  dia- 
phragm and  abdominal  muscles,  then  acts  with  redoubled  effort  to  expel 
its  contents.  The  pains  become  more  acute  and  frequent  ;  the  face  red, 
the  pulse  full  and  frequent,  the  whole  body  seems  to  partake  in  the  affec- 
tion of  the  uterus,  and  is  agitated  with  convulsive  motions.  The  mem- 
branes, filled  with  the  waters,  force  themselves  like  a  wedge,  through  the 
mouth  of  the  uterus,  whose  edges  are  much  weakened ;  the  throes  of  la- 
bour increase  in  strength  and  number,  the  membranes  rupture,  the  liquor 
amnii  escapes,  the  head  of  the  child  follows,  and  it  soon  clears  the  mouth 
of  the  uterus  with  most  excruciating  pains. 

These  pains  are  particularly  severe,  when  the  sacrum  not  being  suffi- 
ciently concave,  the  nerves  of  the  sacral  plexus  are  violently  compressed 
by  the  head  of  the  foetus;  this  part  of  the  body,  almost  always,  presents 
first;  it  passes  through  the  upper  outlet  of  the  pelvis,  in  an  oblique  di- 
rection, the  occiput  being  turned  forward,  and  corresponding  to  one 
of  the  acetabula,  while  the  face  is  directed  backward  towards  one  of 
the  sacro-iliac  junctions.  It  passes  thus  along  the  greatest  diameter  of  the 
pelvis,  but  in  descending  lower  down  in  the  pelvis,  it  describes  a  portion 
of  a  circle,  and  passes  through  the  lower  outlet  of  the  pelvis,  at  its 
greatest  diameter,  which  is  from  the  fore  to  the  back  part.  The  head 
descends  through  the  vagina,  appears  outwardly,  soon  disengages  it- 
self, and  is  followed  by  the  shoulders  and  the  rest  of  the  body.  Thus 
it  is,  that  Nature,  after  having  produced  fecundation  by  an  act  attend- 
ed with  pleasure,  expels  the  product  of  conception  in  the  midst  of 
pain. 

CCXVII.  The  passages,  along  which  the  foetus  is  carried  out  of  the 
body,  would  be  too  confined,  in  their  ordinary  state,  to  allow  expulsion 
to  take  place  without  laceration,  if,  as  I  am  going  to  explain,  Nature 
had  not  disposed  every  thing  to  facilitate  labour.  In  fact  Nature  has 
not  only  formed  the  foetal  skull  of  several  flexible  pieces,  separated  by 
membranous  unossified  spaces,  so  as  to  allow  the  bones  to  move  one 
another,  and  the  whole  head  to  be  reduced  in  size  in  passing  through 
the  female  pelvis;  but  she  has,  besides,  united  the  bones  of  the  pel- 
vis, in  such  a  manner,  that  their  articulations  become  evidently  relax- 
ed towards  the  end  of  pregnancy.  During  the  progress  of  pregnancy, 
the  fluids  of  the  mother  flow,  in  every  direction,  towards  the  pelvis 
and  the  parts  which  it  contains  ;  the  ligamento-cartilaginous  articula- 
tions of  the  pubis,  of  the  sacrum  and  coccyx,  soaked  in  fluids,  unite, 
with  less  firmness,  the  bones  between  which  they  are  placed.  Hence, 
being  softened  and  swollen,  they  do  not  force  them  assunder,  like  a 
•wedge,  by  increasing  their  diameters,  but  facilitate  the  separation  of 
the  bones,  by  the  passage  of  the  head  through  the  pelvis.  Ic  is  on 
the  relaxation  of  the  articulations  of  the  pelvis,  that  the  indication  for 
the  operation  of  dividing  the  symphysis  pubis  rests  ;  an  operation  said 
to  have  been  performed  successfully  by  Sigault  and  by  Professor  Alphonse 
Leroy. 


The  foresight  of  Nature  is  not  limited  to  the  facilitating  the  motion* 
on  one  another,  of  the  osseous  parts  of  the  skull  of  the  foetus,  and  of  the 
pelvis  of  the  motner;  her  care  extends  to  the  soft  parts  of  the  latter; 
these  are  soaked  in  mucus,  so  as  to  reflux  their  tissue  several  days  before 
parturition,  and  are  so  disposed,  as  was  already  observed  (CCI.)  that  they 
may,  without  rupture  or  violence,  and  by  the  mere  unfolding  of  the  folds 
of  the  skin,  yield  to  a  considerable  degree.  As  the  placenta  and  the 
membranes  are  not  expelled  immediately  after  the  foetus,  it  is  customary 
to  separate  them,  by  dividing  the  umbilical  cord,  near  the  navel.  It  is 
unnecessary  to  tie  this  cord,  at  the.  part  near  the  mother,  every  communi- 
cation being  intercepted  between  the  placenta  and  the  uterus,  so  that  no 
blood  could  flow  but  that  of  the  placenta.  Not  so,  however,  with  the 
part  nearest  the  foetus  5  though  the  changes  which  take  place  in  the  cir- 
culation, at  the  moment  when  the  chest  is  dilated,  and  allows  the  air  to 
distend  the  pulmonary  tissue,  divert  the  blood  from  the  umbilical  vessels: 
•these  changes,  however,  in  the  circulation  of  the  fluids,  might  come  on 
slowly,  from  the  weakness  of  the  new  born  child ;  hence  it  is  always 
prudent  to  prevent,  by  a  ligature,  a  loss  of  blood  that  would  increase  the 
debilty., 

The  human  ovum  is  very  seldom  detached  entire,  and  never  so  without 
considerable  danger;  that  is,  the  foetus  is  not  expelled  with  its  -mem- 
branes and  in  the  liquor  amnii,  for  .these  are  not,  in  general,  expelled  till 
a  quarter  of  an  hour,  half  an  hour,  or  even  a  full  hour  after  the  delivery 
of  the  foetus.  When  the  uterus  is  completely  emptied,  its  cavity  be- 
comes obliterated  by  the  approximation  of  its  sides  ;  this  organ,  con- 
tracted on  itself,  sinks  behind  the  pubis,  its  cervix  closes,  and  this  even 
impedes  the  delivery  of  the  after-birth,  when  the  latter  is  protracted  too 
long.  The  parietes  of  the  uterus,  imbued  with  fluids,  are  thicker  than 
in  their  natural  condition  ;  but  they  decrease  in  size,  in  consequence  of 
the  lochial  discharge,  and  return  to  their  wonted  thickness. 

When  labour  is  over,  the  uterus  falls  as  it  were,  asleep,  and  enjoys 
repose,  after  painful  exertion.  The  humours  cease  to  be  determined  to 
that  organ,  towards  which  they  are  no  longer  directed,  by  any  irritation, 
and  they  flow  towards  the  mammary  glands,  to  supply  the  secretion  of 
the  fluid  which  is  to  nourish  the  new  born  child. 

CCXVIII.  Of  twins.  Though,  in  the  human  subject,  the  offspring 
is  generally  single  it  is  not  uncommon  for  a  woman  to  bring  forth  two 
children  at  once;  it  has  even  been  calculated,  that  the  proportion  of  twin 
cases  to  single  births,  was  one  to  eighty.  Indeed,  there  are  cases  of 
women  who  have  brought  three  children  at  a  birth.  Haller  calculates 
that  the  number  of  these  last,  to  those  of  single  births  is  as  one  to  seven 
thousand.  The  cases  of  four  children  at  a  birth,  are  still  less  frequent, 
and  if  three  children  born  at  once,  seldom  live  long,  the  others,  which, 
when  born,  are  at  the  size  of  children  at  five  months,  cannot  live.  Only 
one  or  two  instances  are  known  of  five  children,  having  been  born  at  a 
birth  ;  Haller,  therefore,  is  guilty  of  exaggeration,  in  saying  that  these 
cases  are  to  the  ordinary  cases,  in  the  proportion  of  one  to  a  million.  I 
take  no  notice  of  the  instances  in  which  a  greater  number  are  said  to  have 
been  delivered  at  once,  because  those  cases  are  not  well  authenticated. 
In  the  case  of  twins,  each  child  has  its  own  umbilical  cord  terminating, 
sometimes,  in  a  separate,  and  sometimes  in  a  single  placenta.  Both  foe- 
tuses are  enveloped  in  one  chorion,  but  each  has  a  distinct  amnion,  and 
floats  in  a  separate  liquor  amnii.  It  would  be  curious  to  know,  whether 


415 

in  women  who  have  had  twins,  as  well  as  in  animals,  one  should  find  two 
cicatriculae,  both  in  the  same  ovarium,  or  one  in  each.  Twins  are  gene- 
rally, very  like  one  another,  in  features  and  dispositons. 

The  multiplicity  of  foetuses,  in  the  same  pregnancy,  is  occasioned  by 
the  presence  of  several  vesiculse,  ready  to  be  detached  from  the  ovaria, 
and  consequently  ripe  for  fecundation.  This  multiplicity  of  offspring 
contributes  very  little  to  increase  population,  for,  they  are,  in  general,  less 
robust  and  strong,  and  not  so  capable  of  reproduction ;  they,  besides,  ex- 
haust the  strength  of  the  mother,  and  their  birth  is  often  fatal  to  her. 
The  number  of  children  which  a  woman  might  bring  into  the  world, 
from  the  period  of  puberty  to  the  cessation  of  the  menstrual  discharge, 
would  be  much  greater  than  it  generally  is,  if  no  time  were  lost.  Some 
women  have  been  know  to  have  twenty-four,  thirty,  thirty-nine,  and  even 
fifty-three  children.  A  woman  died  in  North-America,  after  having  had 
five  hundred  children  and  grandchildren,  of  whom  two  hundred  and  five 
survived  her. 

It  is  now  well  known,  that  the  number  of  male  children  who  are  born, 
exceeds,  in  general,  that 'of  the  females.  The  difference,  in  some  coun- 
tries, is  estimated  at  one  in  twenty-one,  at  a  fourteenth,  a  twelfth,  and 
sometimes,  though  rarely,  at  a  third.  In  all  countries  of  the  world,  poly- 
gamy is,  therefore,  in  direct  opposition  to  the  intentions  of  Nature,  and 
to  the  multiplication  of  the  species  :  this  is  proved,  in  a  most  undeniable' 
manner  by  the  loss  of  population  in  those  countries  in  which  this  practice 
exists.  The  boys,  more  numerous  than  the  girls,  during  the  early  part  of 
life,  exposed  afterwards,  to  the  dangers  of  war,  of  navigation,  and  occu- 
pied in  laborious  occupations,  lead  a  more  laborious  and  anxious  life,  and 
die  in  great  numbers,  so  that  the  equilibrium  is  soon  restored,  and  the 
least  numerous  portion  of  the  human  species,  at  the  cradle,  forms  about 
two-thirds  of  it,  in  old  age,  since  we  always  see  more  women  than  men 
reach  a  very  advanced  age. 

CCXIX.  Of  superf delations.  The  cases  of  foetuses  bom  with  unequal 
degrees  of  deveiopemerit,  are  not  to  be  considered  as  superfoetations, 
but  as  twin  cases.  Thus,  if  in  a  case  of  twins,  one  foetus  is  of  its  full 
size,  while  the  other  is  an  embryo  whose  size  does  not  exceed  that  of  a 
foetus  in  the  first  month;  it  does  not  follow  that  their  conception  took 
place  at  different  and  distinct  periods,  but  merely  that  for  some  reason 
or  other,  one  of  the  germs  has  been  incapable  of  growth  and  develope- 
ment. 

To  settle  the  question  of  superfoetations,  one  should  know  whether  a 
woman,  with  a  single  uterus,  is  capable  of  conceiving  two  months  after 
effective  copulation.  Haller  is  of  opinion,  that  the  cervix  of  the  uterus 
is  always  open  to  the  semen  ;  but  how  is  the  latter  to  reach  the  ovaria, 
through  the  adhesions  of  the  chorion  to  the  uterus?  It  appears  easier, 
where  the  two  conceptions  are  separated  by  a  short  interval  ;  thus,  the 
white  woman  mentioned  by  Buffon,  who,  in  the  course  of  one  morn- 
ing, had  connexion  with  her  husband  and  with  a  negro  slave,  bore  two 
children  of  different  colours.  Hence,  likewise,  it  sometimes  happens 
that  one  of  two  twins  is,  by  its  features,  a  living  testimony  of  adul- 
tery. 

Two  children,  born  with  an  interval  of  some  months  between  their 
births,  cannot  be  considered  as  twins,  though  they  may  have  existed  some 
time  together  within  the  mother's  womb.  The  possibility  of  such  super- 


414 

foetations  is  well  proved  ;  they  are  ascribed  to  septa,  dividing  the  uterus, 
sometimes,  into  two  cavities,  merely  because  such  an  arrangement  would 
explain,  to  a  certain  degree,  how  two  conceptions  might  take  place,  at 
some  interval  from  one  another ;  for  it  has  never  been  ascertained,  by 
actual  dissection,  that  any  woman,  in  whom  such  superfoetations  took 
place,  had  a  double  uterus*. 

CCXX.      Of  suckling.     Nothing  is  more  generally  known  in  physio- 
logy, than  the  strict  sympathy  which  subsists  between  the  uterus  and 


*  It  seems  to  me,  that  a  belief  in  superfoetations  can  hardly  be  entertained  by  any  one 
•who  is  conversant  with  the  human  economy,  and  particularly  with  the  changes  which 
the  uterine  system  undergoes  in  consequence  of  pregnancy.  We  know  that  soon  after 
conception,  the  os  tincae,  as  well  as  the  internal  apertures  of  the  fallopian  tubes,  are 
closed  by  -a  deposition  of  a  thick  tenacious  mucus.  But  to  accomplish  still  more  per- 
fectly an  end  so  important  to  the  scheme  of"  generation  as  the  occlusion  of  the  uterus, 
nature  resorts  to  another  provision. 

By  the  sprouting  forth  of  minute  blood  vessels*,  or  by  the  effusion  of  a  species  of 
lymph-j-,  or  out  of  coagulated  bloodt,  a  membrane  of  some  firmness  of  texture  is  quick- 
ly formed.  This  membrane,  which  is  called  decidua  or  caduca,  from  its  being  shed  at 
the  period  of  delivery,  lines  completely  the  uterus,  and  thus  co-operates  with  the  dense 
mucus  already  alluded  to,  in  obliterating  the  three  openings  into  its  cavity. 

Such  too,  is  the  enlargement  of  the  gravid  uterus,  and  the  change  thereby  produced 
in  the  relative  position  of  its  appendages,  that  a  new  series  of  impediments  arises  to  the 
frustration  of  a  second  conception. 

In  this  state  of  the  organ,  it  is  accurately  ascertained,  that  the  tubes  lie  parallel  to  its 
sides,  and  subsequently  in  the  progress  of  gestation,  become  bound  in  the  same  situa- 
tion, instead  of  running  in  a  transverse  direction  towards  the  ovaries,  with  their  extremi- 
ties lower  and  fluctuating. 

Were  an  embryon,  therefore,  to  be  generated  by  any  anamolous  combination  of  circum- 
stances, the  tubes  could  not  possibly  embrace  the  fecundated  vesicle,  and  the  embryon, 
of  course,  must  remain  in  the  ovary,  or  fall  into  the  abdomen,  constituting  an  extra 
uterine  conception. 

Let  us,  however,  withdraw  all  the  obstacles  which  have  been  enumerated  to  the  pass- 
age of  the  embyron,  and  admit  the  practicability  of  its  reaching  the  uterine  cavity.  What 
in  this  event  would  happen  ?  Disorganization'fatal  to  each  foetus  must  ensue. 

It  is  to  be  recollected,  that  the  uterus  had  prepared,  in  the  first  instance,  whatever 
was  required  for  the  reception,  the  nourishment,  and  evolution  of  the  foetus.  It  had  ori- 
ginally supplied  it  with  a  decidua,  as  a  medium  of  attachment,  and  afterwards  with  a 
placenta  for  still  more  important  purposes.  For  the  second  foetus,  the  same  offices  are  to 
be  rendered.  These  it  it  could  not  execute,  without  suspending  the  action  existing  at 
the  time,  and  taking  on  such  as  are  necessary  to  the  fabrication  of  an  additional  deci- 
dua and  placenta. 

That  actions  so  incompatible  cannot  co-exist,  strikes  me  as  sufficiently  obvious.  Were 
the  uterus,  therefore,  to  attempt  this  new  process,  the  result  would  be,  the  separation 
of  the  primary  decidua  and  placenta,  occasioning  an  abortion,  accompanied  with  haemorr- 
hage, which  would  sweep  out  the  whole  of  its  contents. 

It  is  probably,  on  this  account,  that  menstruation  uniformly  ceases  with  the  accession 
of  pregnancy.  I  am  aware,  that  this  is  a  point  not  altogether  conceded.  The  weight 
of  authority  is  however,  decidedly  against  menstruation  continuing  dnring  gestation.  By 
all  the  very  recent  writers  it  is  denied.  Those  who  hold,  or  I  might  rather  say,  did 
hold  the  contrary  opinion,  have  mistaken  a  hemorrhage  from  the  vagina,  which  some- 
times recurs  with  considerable  periodical  regularity,  for  the  catamenial  flux.  Several 
cases  of  this  kind  have  come  under  my  own  observation,  where  I  had  an  opportunity  of 
inspecting  the  discharge  accurately.  In  every  instance,  I  found  it  pure  coagulable  blood 
having  neither  the  colour,  nor  odour,  nor  any  other  of  the  peculiar  properties  of  the 
genuine  menstrual  fluid. 


Haller.  f  Dr.  Hunter.  *  Mr.  Hunter. 


415 

rnammce ;  a  connection,  in  consequence  of  which,  these  two  organs  are 
called  into  action  at  the  same  period  of  life,  are  evolved,  and  cease  to 
perform  their  functions  at  the  same  time,  when  woman  becomes  incapa- 
ble of  co-operating  in  the  reproduction  of  the  species.  I  shall  not  en- 
deavour to  account  for  this  sympathy,  by  ascribing  it  to  the  influence  of 
the  nervous  system,  or  to  the  anastomosis  of  the  epigastric  with  the  in- 
ternal mammary  arteries  :  an  anastomosis  which  is  not  uniform,  for,  in- 
stead of  inosculating  with  each  other,  these  vessels  frequently  terminate 
in  the  recti  muscles  of  the  abdomen.  But  even  though  this  anastomo- 
sis, should  exist,  as  distinctly  as  it  is  often  met  with  in  some  subjects, 
it  would  not  account  for  this  sympathy,  since  the  uterus  and  the  mam- 
mae often  receive  no  branches  from  the  epigastric  and  mammary  arteries, 
and  when  they  do  they  are  exceedingly  small. 

The  new  born  child,  on  being  brought  in  contact  with  the  breast,  ap- 
plies his  mouth  to  the  nipple,  and  withdrawing  his  tongue,  while,  with 
his  lips,  he  compresses  the  edges  of  the  nipple,  he  draws  in  the  fluid, 
whose  flow  is  facilitated  by  the  erection  of  the  lactiferous  tubes.  These 
ducts,  from  twelve  to  fifteen  in  number,  not  only  become  enlarged,  when 
the  nipple,  which  almost  entirely  consists  of  them,  is  elongated  by  being 
drawn  out  by  the  child,  but,  besides,  being  excited  by  his  touch, 
they  become  affected  with  a  certain  degree  of  erection,  and  emit  their 
fluid.  This  excretion,  like  that  of  other  glands,  is  excited  by  the  touch 
and  the  motion  of  the  hands  of  the  child  on  his  nurse's  breast.  The  use  of 
these  gentle  compressions,  is  not  so  much  to  express  the  milk  mechani- 
cally, as  to  excite  the  organ  to  excretion. 

The  irritation  produced  by  the  child  on  the  nipple,  is  the  most  power- 


By  again  adverting1  to  the  condition  of  the  pregnat  uterus,  we  shall  see  that  a  suppres- 
sion of  the  catamenia  is  exactly  what  ought  to  expected.  The  deciduous  membrane  is 
framed  while  the  process  of  conception  is  proceeding  in  the  ovary.  The  vessels  which 
had  secreted  the  catamenia  are  now  engaged  in  a  new  operation.  They  form  the  mem- 
brane and  then  support  it.  While  thus  employed,  their  secretory  function  is  suspend- 
ed. They  cannot  at  the  sume  period,  perform  actions  so  incongruous  and  inconsistent. 
The  one  must  yield  to  the  other.  This  is  very  strikingly  illustrated  by  the  fact  which 
has  not  been  sufficiently  attended  to,  that  in  a  large  proportion  of  the  cases  of  obstinate 
umenorrhea,  the  membrana  decidua  exists,  and  that  the  first  symptom  of  the  return  of 
the  discharge  is  the  coming  away  of  the  membrane.  Of  the  identity  of  the  two  mem- 
branes, there  can  be  no  doubt.  It  has  been  determined  by  very  competent  judges*. 

By  one  less  averse  than  myself  to  speculative  reasonings  in  matters  of  science,  a  va- 
riety of  considerations  of  this  nature,  might  be  pressed  against  the  hypothesis  which  I  am 
combating.  It  could,  I  think,  in  particular,  be  urged  with  great  plausibility,  that  chang- 
ed as  is  the  whole  uterine  system  by  gestation,  not  only  in  the  mechanical  distribution, 
but  also  in  the  structure  and  functions  of  its  parts,  it  cannot  possibly  assume  that  peculiar 
condition  which  seems  indispensable  to  conception.  Of  all  the  operations  of  the  ani- 
mal economy,  that  of  conception  undoubtedly  requires  the  most  harmoniously  concert- 
ed action  in  the  several  organs  by  which  it  is  commenced,  carried  on  and  consummated. 
Derangements  in  any  one  portion  of  this  complex  apparatus  are  confessedly  productive 
of  sterility.  So  essential,  indeed  to  the  generative  process  in  the  human  species,  is  a 
perfect  integrity  in  the  functions  of  the  uterine  system,  that  by  the  suppression  or  even 
vitiation  of  the  catamenia,  the  aptitude  to  conception  is  lost  or  diminished.  But  enough 
of  these  speculations  ;  1  am  content  to  rest  the  defence  of  the  question  on  the  facts 
which  I  have  stated.  If  they  be  correct,  it  results  that  superfcctation  cannot  take  place 
in  the  human  species.—  Chapman. 

*  Baillie,  Burns,  &c.  &c. 


416 

fill  exciting  cause  of  the  determination  of  milk  into  the  breasts  j  thru  ir- 
ritation, or  any  other  of  the  same  kind,  issufficient  to  excite  the  secretion 
of  milk,  even  under  circumstances  not  provided  for  by  Nature.  It  is 
thus  that  virgins  have  been  enabled  to  suckle  another  mother's  child  ; 
that  young  girls,  under  the  age  of  puberty,  have  had  so  complete  a  secre- 
tion of  milk,  as  to  furnish  a  considerable  quantity  of  this  fluid.  There 
have  been  known  men,  in  whom  a  long  continued  titillation  of  the  breasts 
had  determined  so  considerable  an  afflux  of  the  humours,  that  there 
oozed  from  them  a  whitish,  milky,  and  saccharine  fluid,  not  unlike  the 
milk  of  a  woman.  The  sucking  of  the  new-born  child,  is  necessary  to 
keep  up  the  secretion  of  milk  in  the  mammae.  It  ceases  to  be  formed  in 
them,  when  the  child  is  committed  to  the  care  of  a  different  nurse  :  the 
mammae,  at  first  turgid,  soon  collapse,  especially  if  care  have  been  taken 
to  determine  the  fluids  downwards,  by  exhibiting  gentle  laxatives. 

The  erection  of  the  breasts,  by  titillation  on  the  nipple,  the  spasmodic, 
and  almost  convulsive,  action  which  follows  this  kind  of  excitement,  may 
be  carried  so  far  as  to  produce  an  emission  of  the  fluid  to  some  distance. 
While  its  excretion  lasts,  women  experience,  in  their  breasts,  an  agreea- 
ble sensation  ;  these  parts  are  tense  and  swollen  ;  they  feel,  as  they  express 
it,  the  milk  rising;  several  feel  a  sensation  of  extension  reaching  to  the 
axilla,  to  the  arms  and  chest.  The  whole  mass  of  cellular  substance  sur- 
rounding the  breasts  and  extending  to  the  neighbouring  parts,  partakes 
in  their  activity. 

The  breasts,  themselves,<:onsist,  in  great  measure,  of  cellular  substance? 
an  adipose  and  lymphatic  layer,  of  a  certain  thickness,  covers  the  gland, 
•vvhich  is  divided  into  several  lobes,  and  incloses  it  within  its  substances. 
They  receive  a  number  of  nerves,  but  very  few  blood-vessels  for  their 
bulk. 

Their  structure  appears  almost  wholly  lymphatic  ;  the  vessels  of  this 
kind,  after  being  distributed  to  the  neighbouring  glands,  and  especially 
to  those  of  the  axilla,  penetrate  into  the  breasts,  in  which  their  propor- 
tion, compared  to  that  of  the  sanguineous  vessels,  is  as  eight  to  one. 
These  lymphatic  vessels,  which  enter  in  considerable  numbers  into  the 
composition  of  the  breasts,  increase  greatly  in  size  in  nurses  ;  and  when 
injected  in  this  condition,  it  has  been  ascertained,  that  several  of  them 
joined  to  form  larger  trunks,  which,  going  towards  the  nipple,  contribu- 
ted in  forming  what  are  called  the  lactiferous  tubes.  If  the  lymphatic 
vessels  be  immediately  continuous  with  the  excretory  ducts  of  the  breasts, 
there  is  reason  to  believe,  that  it  is  these  vessels  which  convey  the  mate- 
rials of  the  fluid  which  they  separate,  especially  if  it  be  considered,  how 
small  the  number  of  minute  arteries  which  are  distributed  into  their  tissue, 
and  what  a  disproportion  there  is  between  the  calibre  of  these  small  ves- 
sels, and  the  quantity  of  blood  which  the  breasts  supply.  The  opinion 
that  the  lymphatic  vessels  bring  to  the  breasts  the  materials  of  the  secre- 
tion of  milk,  is  not  in  opposition  to  the  laws  of  the  circulation  in  the  lym- 
phatics;  all  who  are  acquainted  with  these  laws,  know  that  the  course 
of  the  lymph,  though  in  general,  from  the  circumference  to  the  centre, 
is  naturally  liable  to  a  number  of  aberrations  or  deviations,  facilitated  by 
the  numberless  anastomoses  of  these  vessels. 

CCXXI.  The  granulated  structure  is  not  as  apparent  in  the  breasts,  as 
hi  the  other  glandular  organs,  hence  they  bear  a  greater  resemblance  to 
the  lymphatic,  than  to  the  conglomerate  glands.  The  milk  which  they 


417 

secrete,  has  always  been  considered  as  very  like  the  chyle,  which  it  re- 
sembles in  its  white  colour,  its  smell,  and  its  saccharine  taste.  Like  the 
chyle,  it  is  the  least  animalized  fluid,  the  sweetest,  that  on  which  the  ac- 
tion of  the  organs  produces  the  least  effect,  and  that  which  preserves 
most  the  characteristic  qualities  of  the  food  taken  by  the  nurse. 

It  is  well  known,  that  instead  of  giving  medicines  to  infants  at  the 
breast,  we  most  frequently  administer  the  medicine  to  the  nurse  ;  thus, 
the  milk  acquires  purgative  qualities,  and  acts  on  the  bowels  of  the  child, 
when  the  nurse  has  been  purged*.  The  chyle  is  white  and  opaque,  only 
in  those  animals  which  suckle  their  young ;  in  the  others,  it  is  as  trans- 
parent as  lymph.  (Cuvier.) 

In  the  last  place,  if  the  arteries  carried  to  the  breasts  the  materials  of 
their  secretion,  these  vessels  ought  to  increase  in  size,  when  these  organs 
become  twice,  or  even  three  or  four  times  larger  than  natural;  in  the 
same  manner  that,  in  open  cancer,  and  in  other  similar  affections,  in 
jwr.hich  the  determination  of  blood  being  increased,  the  calibre  of  the  ves- 
sels is  proportioned  to  them.  Nothing,  however,  of  the  same  kind  occurs, 
whatever  size  the  breasts  may  acquire  from  the  presence  of  milk  ;  their 
arteries  preserve  their  almost  capillary  minuteness,  as  I  had  an  oppor- 
tunity of  ascertaining,  by  injecting  the  mammae  of  a  woman  twenty-nine 
years  of  a|*e,  who  died  in  the  second  month  of  suckling,  and  whose  breasts 
were  remarkable  by  their  size,  and  by  the  quantity  of  milk  they  were  able 
to  secrete. 

Notwithstanding  all  these  reasons,  which  have  long  made  me  adopt  the 
opinion  of  the  celebrated  Haller,  who  considers  the  milk  as  immediately 
extracted  from  the  chyle,  I  own  that  it  must  be  considered  as  hypotheti- 
cal, and  resting  solely  on  probability.  The  impossibility  of  demonstra- 
ting, anatomically,  the  branches  going  from  the  mesentery  to  the  breasts, 
without  communicating  with  the  thoracic  duct,  gives  still  greater  proba- 
bility to  the  generally  received  opinion,  which  makes  the  milk,  like  all 
the  other  secreted  fluids,  with  the  exception  of  the  bile,  to  be  supplied  by 
arterial  bloodf. 

The  milk  does  not  resemble  chyle,  in  every  respect,  though  it  may  .be 
considered  as  extracted  from  the  food|,  changed  in  its  way  to  the  mam- 
mae, by  the  glands  through  which  it  has  passed,  and  especially  by  the  ac- 
tion of  the  organs  themselves.  This  action  is  so  evident,  that,  as  Bordeu 
observes,  "There  are  women  who  seem  to  have  no  milk  in  their  breasts, 
which  are  flaccid  and  empty ;  but  as  soon  as  the  child  excites  them,  they 
become  distended,  and  the  milk  comes  spontaneously."  It  is  well 
known,  and  the  same  author  has  pointed  it  out,  that  women,  cows,  and 
the  females  of  other  animals,  allow  themselves  more  willingly  to  be  sucked 
by  a  suckling  that  knows  how  to  excite  their  sensibility,  and  to  apply  due 
iritation  to  the  nipple ;  and  that,  on  the  contrary,  they  retain  their  milk, 


*  This  only  takes  place  when  such  purgatives  are  used  as  are  readily  absorbed  into 
the  circulation.—  Copland. 

f  The  passage  of  injections  from  the  arteries  into  the  lactiferous  tubes,  and  the  cir- 
cumstance of  blood  having1  been  drawn  from  an  exhausted  breast,  when  the  child  has 
been  allowed  to  suck  too  Jong- ;  and,  lastlj;,  analogy,  leave  no  doubt  of  the  true  source 
of  the  fluid  secreted  by  the  mainmie. —  Copland. 

"  Lac  utilis  aliment!  superfluum."     Gal.  De  Usu  part.  Lib.  VII.  Cap.  XXII. 


418 

\vhen  the  suckling  does  not  excite  the  sensation  in  which  they  feel  plea* 
sure.  It  is  thought,  in  some  countries,  that  serpents  know  how  to  tickle 
the  teats  of  cows,  and  that  these  animals  enjoy  this  excitement,  and  allow 
themselves  to  be  sucked  by  these  reptiles. 

CCXXII.  Of  t  fie  physical  firofierties  of  milky  and  of  the  chemical  nature  of 
this  fluid.  The^  quantity  of  milk  is,  in  general,  proportioned  to  that  of 
the  aliments,  to  the  degree  of  their  nutritious  qualities,  to  their  moist 
and  farinaceous  nature.  Though  it  equals,  in  weight,  about  one-third  of 
the  quantity  of  food  taken  by  the  nurse,  it  may  exceed  that  proportion, 
or  may  not  come  up  to  it.  Its  specific  gravity,  even  when  the' milk  is 
.lightest,  is  greater  than  that  of  distilled  water,  and  is  always  proportioned 
to  its  consistency.  The  latter  quality  is  in  an  inferior  degree,  in  woman,  but 
is  greater  in  the  cow,  the  goat,  the  ass,  and  the  ewe.  Its  fluidity  is  interme- 
diate between  that  of  aqueous  and  oily  liquids,  its  colour,  its  smell  and  fla- 
vour have  something  very  peculiar,  and  by  which  it  is  easily  recognized; 
in  the  last  place,  it  is  not  exactly  alike,  at  different  periods  of  the  same 
milking.  This  is  proved  by  the  work  of  Messrs.  Deyeux  and  Parmentier 
on  milk,  a  work  abounding  in  valuable  observations,  and  which  may  be 
considered  as  the  complete  history  of  this  animal  fluid.  They  observed, 
that  the  milk  first  drawn  from  the  cow  is  serous,  that  its  consistency  gra- 
dually increases,  and  that  the  richest  milk  is  that  which  is  obtained  to«- 
wards  the  end  of  milking,  as  if  the  fluid  contained  in  the  udder  were  af- 
fected by  the  laws  of  gravitation*. 

The  milk,  when  exposed  to  the  open  air,  in  a  vessel,  becomes  decom- 
posed, like  the  blood,  and  separates  into  three  parts  ;  the  serum,  the 
curd  or  cheesy  part,  and  the  fatty  part  or  cream.  The  latter,  which  is 
lighter  than  the  others,  is  always  on  the  surface,  and  its  quantity  depends, 
not  only  on  the  richness  of  the  milk,  but  also  on  the  extent  of  the  surfaces 
by  which  it  is  in  contact  with  the  air;  and  this  proves,  as  was  first  ob- 
served, by  Fourcroy,  that  the  oxygen  of  the  atmosphere  has  some  influ- 
ence on  its  separation.  The  caseous  part,  which  coagulates  spontane- 
ously, appears  albuminous,  and  abounds  in  oxygen.  MM.  Parmentier 
and  Deyeux  consider  it  as  the  colouring  matter  of  milk,  and  as  giving  to 
it  its  most  characteristic  properties.  Lastly,  the  serum  or  whey,  which 
alone  constitutes  the  greatest  part  of  this  fluid,  contains,  besides  a  pecu- 
liar acid,  (the  lactic  acid']  which  is  formed  when  this  substance  is  allowed 
to  remain  for  some  time,  a  saccharine  matter,  which  may  be  obtained  by 
evaporation,  and  which,  when  chrystallized  in  rhomboidal  parallepipeds, 
constitutes  the  sugar  of  milk,  whose  purity  depends  on  the  degree  of  care 
with  which  the  process  has  been  carrkd  on.  This  sugar  of  milk  con- 
tains, as  Schele  first  "ascertained,  while  endeavouring,  by  means  of  the 
nitric  acid,  to  convert  it  into  the  oxalic,  a  peculiar  acid,  in  the  form  of  a 
powder,  difficult  of  solution,  and  to  which  he  gave  the  name  of  saclatic 
acid.  Milk  may  be  considered  as  one  of  the  most  compound  of  the  ani- 
rnal  fluids,  whose  qualities  are  very  valuable,  and  whose  parts  have  but 
an  imperfect  affinity  to  each  other.  So  that  it  is  liable  to  spontaneous 
decomposition,  and  this  takes  place  very  easily.  This  kind  of  emulsion 
contains  but  a  small  quantity  of  asote,  so  that  it  retains  its  vegetable  charao 


*  The  author  seems  to  forget  that  he  is  speaking  of  the  cow,  and  that  her  uddci' 
hangs  in  a  situation  unfavourable  to  this  hypott»csis.--~7y«7#!?'. 


ter.  Hydrogen,  carbon,  and  oxygen,  predominate  in  milk ;  in  the  last 
place,  it  contains  several  salts,  amongst  others,  muriate  of  soda,  muriate 
of  potash,  and  phosphate  of  lime*. 

The  presence  of  the  two  last  of  these  substances  leads  to  the  following 
considerations.  Muriate  of  potash,  as  is  observed  by  Rouelle,  does  not 
exist  in  the  blood  ;  the  probability  is,  therefore,  that  it  is  not  the  blood 
which  supplies  the  mammae  with  the  materials  whence  the  milk  is  se- 
creted, muriate  of  potash  being  found  in  greater  quantity  in  milk  than 
muriate  of  soda.  These  salts  of  potash,  on  the  contrary,  are  found  in 
considerable  proportions  in  the  chyle,  formed  from  vegetable  substances; 
which  would  lead  one  to  think,  that  milk  is  furnished  by  the  absorbent 
system.  The  phosphate  of  lime,  which  is  found  in  smaller  quantity  in 
the  urine  of  nurses,  and  which  is  wholly  determined  towards  the  mammae, 
was  absolutely  necessary  in  a  fluid  which  supplies  nourishment  to  the  new 
being,  while  the  bones  become  indurated,  and  all  the  parts'acquire  soli- 
dity. 

If  we  now  wish  to  inquire  into  the  causes  which  render  suction  neces- 
sary, and  which  subject  the  new  born  child  to  this  peculiar  mode  of  nu- 
trition, these  causes  will  be  found  in  the  general  weakness  of  its  organs. 
The  organs  of  digestion  would  have  been  incapable  of  extracting,  from 
the  aliments,  their  nutritive  parts,  these  substances  not  having  undergone 
the  due  degree  of  trituration,  from  the  want  of  teeth  and  from  the  im- 
perfect state  of  the  other  organs  of  mastication,,  It  was  of  consequence, 
therefore,  that  the  mother  should  perform  the  preliminary  function,  and 
that  she  should  transmit  the  aliment  ready  digested!.  It  is  not,  however, 
to  be  imagined,  that  the  milk  passes,  without  undergoing  any  change, 
into  the  vessels  of  the  child  5  the  child  digests  the  milk,  and  obtains  from 
it,  in  a  short  space  of  time,  and  without  effort,  a  considerable  quantity  of 
nutritious  particles,  necessary  to  the  rapidity  of  its  growth. 

The  connexion  between  the  mother  and  childis  far' from  being  broken, 
at  the  period  of  birth  5  the  relations  between  them,  though  not  so  close, 
are  uot  less  indispensable.  Before  birth,  the  vital  power  was  so  limited 
in  the  child,  that  it  was  necessary  it  should  receive  a  fluid  already  anima- 
lized,  and  in  a  state  to  yield  to  the  function  of  assimilation  and  nutrition. 
When  the  child  has  breathed,  when  its  strength  is  increased,  it  may  be 
entrusted  with  a  greater  share  of  the  process ;  it  is  then  sufficient  that 
the  aliment  should  have  undergone  the  first  degree  of  elaboration,  within 
the  digestive  canal.  But  it  is  not  merely  to  assist  in  preparing  its  food, 
that  the  new  born  child  requires  the  aid  of  the  mother;  its  lungs,  which 
are  delicate  and  imperfectly  evolved,  do  not  supply  a  due  quantity  of  oxy- 
gen to  the  blood  which  circulates  through  them  :  the  animal  heat  would 
be  under  what  is  required  by  the  wants  of  life,  if  the  mother  did  not  make 
up  for  this  deficiency,  by  transmitting  some  of  her  own  warmth.  She 
folds  her  infant  gently  to  her  bosom,  warms  it  with  her  breath,  and  by 
this  kind  of  maternal  incubation  continues  to  cherish  it  with  that  calori- 
fic influence  to  which  it  was  fully  exposed,  while  forming  a  part  of  her- 
self. Besides,  she  feels  for  it,  keeps  it  from  danger,  foresees  its  wants, 
and  understands  its  language  ;  and  this  very  interesting  intercourse  takes 


*  See  the  Chapter,  at  the  end  of  the  APPENDIX,  on  the  Chemical  Constitution  of  the 
Secretions. 
f  Lac  est  dbus  exacts  con/ectus.     Galenus  DeUsu  partium.     Lib.  VII.  cap.  XXU= 


,  420 

place  after  the  bonds  of  their  physical  communication  are  loosened,  but 
it  does  not  tear  them  asunder.  The  infant  is,  therefore,  detached  from 
the  mother,  only  by  degrees,  since  it  is  only  in  proportion,  as  it  grows 
older,  that  it  acquires  the  means  of  living  independent. 

The  secretion  of  milk,  in  the  breasts,  may  be  prevented  by  irritation 
in  the  uterus.  If  the  labour  have  been  difficult,  if  the  woman  have  suf- 
fered a  certain  degree  of  injury,  the  irritation  in  the  parts  so  affected 
prevents  the  determination  of  the  fluids  towards  the  mammae.  Hence 
these  organs  collapse,  during  the  puerperal  fever,  not  that  the  milk  flows 
back  into  the  fluids  and  becomes  the  cause  of  the  complaint,  but  that 
the  inflammation  of  the  uterus,  prevents  the  fluids  from  flowing  in  their 
natural  direction. 

During  the  first  few  days  after  delivery,  the  parietes  of  the  uterus  dis- 
tharge  a  fluid  at  first  bloody,  then  of  a  reddish  colour,  and,  in  the  last 
place,  mucous  and  whitish,  termed  the  iochia. 

CCXXIII.  All  the  parts  of  the  lungs  are  not  distended  with  air,  in  the 
first  inspirations  of  the  child,  after  birth.  Some  of  the  lobes,  which  are 
harder  and  more  compact,  take  some  time  to  admit  this  fluid,  and  even 
sometimes  altogether  reject  it.  A  child  died,  twenty-one  days  after  birth, 
the  body  was  opened  by  Professor  Boyer.  On  examining  the  lungs,  he 
found  that  the  posterior  part  of  these  organs  was  as  hard  and  compact, 
as  in  the  foetal  state.  The  anterior  part  alone  was  distended,  contained 
air,  could  be  felt  to  crepitate,  and  floated  in  water.  The  heart  was  ex- 
amined, ta  ascertain  whether  its  structure  was  connected  with  this  con- 
dition of  the  lungs,  which  depended  on  the  want  of  power  in  the  respira- 
tory functions.  The  foramen  ovaie  was  found  pervious,  so  that  the  blood 
could  pass  from  the  right  into  the  left  cavities  of  the  heart,  without  flow- 
ing through  the  lungs.  The  child  had  been  exceedingly  languid  during 
the  whole  of  its  short  life  ;  its  skin  was  at  times  pale,  at  others  livid.  It 
was  very  difficult  to  keep  it  warm. 

The  child  of  Madame  L****  died  nine  days  after  birth,  with  the  same 
appearances.  I -opened  the  chest,  and  found  the  upper  part  of  both  lungs 
indurated  and  compact ;  the  foramen  ovale  was  quite  pervious.  This 
aperture  is  often  closed  very  imperfectly,  so  that  there  remains,  at  the 
upper  part  of  it,  an  opening,  varying  in  size,  which  would  enable  a  small 
quantity  of  venous  blood  to  pass  from  the  right  into  the  left  auricle,  if 
these  cavities  did  not  contract  at  the  same  moment,  and  if  the  fluid  which 
they  contain  did  not  present  equal  resistance  on  both  sides.  There  are 
cases  of  persons  in  whom  the  foramen  ovale  remained  pervious,  and  who, 
nevertheless,  lived  to  an  advanced  age.  Their  skin  was  purple  and 
livid,  all  their  moral  and  physical  faculties  feeble  and  torpid.  It  would 
be  interesting  to  ascertain,  by  dissection,  whether  in  good  divers,  who 
can  remain  a  long  while  under  water,  without  breathing,  the  foramen 
ovale  is  not  imperfectly  closed. 


*  Granting  that  the  foramen  remained  open,  we  do  not  perceive  any  advantage  it 
would  confer.  The  system  requires  blood  purified  or  changed  by  respiration  ;  the  free 
transmission  of  impure  or  venous  blood  from  the  right  to  the  left  side  of  the  heart,  could 
not  answer  the  purpose  of  sustaining  life,  nor  would  it  enable  the  diver  to  remain  for 
any  longer  time  without  respiring.  In  professed  divers  it  is  habit  alone  which  enables 
them  to  remain  so  long  under  water  with  impunity. — Godman- 


421 


CHAPTER    XL 

\ 

Containing  the  History  of  the  dges,  the  Temperaments,  and  the    Varieties  of 
the  Human  Species  /  of  Death,  and  Putrefaction, 


CCXXIV.  Of  infancy.  The  epidermis  of  the  new-born  babe  thickens, 
the  redness  of  the  skin  grows  paler,  the  wrinkles  are  effaced,  the  soft 
down  which  covered  the  face,  falls  and  disappears,  the  buttocks  swell  out 
and  soon  conceal  the  opening*  of  the  rectum.  During  the  first  months  of 
life,  it  seems  to  need  nothing  but  nourishment  and  sleep.  In  the  mean, 
while,  the  understanding  is  beginning  to  form,  it  looks  fixedly  at  objects, 
and  seeks  to  take  cognizance  of  all  the  bodies  that  surround  it.  Confin- 
ed, at  first,  to  the  uneasy  sensations,  which  it  expresses  by  almost  continu- 
al tears,  its  existence  becomes  less  painful,  as  it  grows  accustomed  to  the 
impressions  of  outward  things  upon  its  delicate  organs.  Towards  the 
middle  of  the  second  month,  it  becomes  capable  of  agreeable  sensations. 
If  it  feels  them  before  that  time,  at  least  it  is  only  then  that  it  begins  to 
express  them  by  laughing*. 

CCXXV.  Dentition.  Towards  the  end  of  the  seventh  monthf,  the  mid- 
dle incisor  teeth  of  the  upper  jaw,  cut  through  the  substance  of  the  gums: 
a  little  while  after,  the  corresponding  incisors  of  the  lower  jaw  show 
themselves  :  next,  the  lateral  incisors  of  the  upper  jaw,  those  of  the  low- 
er, then  the  cuspidati,  in  the  same  order.  At  the  age  between  eighteen 
months  and  two  years,  the  small  molar  teeth  appear,  but  in  reversed  or- 
der, those  of  the  lower  preceecling  those  of  the  upper  jaw.  When  these 
molar  teeth  have  come  through,  the  first  dentition  is  complete  ;  the  life 
of  the  child  is  more  secure  :  it  was  before  very  uncertain,  since  the  calcu- 
lations of  the  probable  duration  of  human  life  show,  that  a  third  of  the 
children  born  at  any  given  time,  die  before  the  age  of  twenty-three  months. 
Convulsions  and  diarrheas  are  the  most  fatal  accidents  attending  difficult 
dentition.  To  these  twenty  teeth  are  added  two  new  grinders  in  each 
jaw,  when  the  child  has  reached  the  end  of  his  fourth  year.  These  last 


*  At  Hercules  risus  praecox  ille  et  celerrimus,  ante  quadraffesimum  diem  nulli  datur. 
Plin.  Hist.  Nat.  Pr<ef.  ad  lib.  VIII. 

t  It  would  be  very  difficult  to  say,  why  a  tertian  fever  often  terminates  of  itself,  when 
it  has  reached  its  seventh  paroxysm,  whilst  a  continued  fever  is  judged  of  by  critical 
evacuations,  in  seven,  fourteen,  or  twenty-one  days ;  why  delivery  happens  at  the  end 
of  nine  months  :  why  the  first  teething-  begins  at  seven  months  old,  the  second,  at  seven 
years;  why  puberty  shows  itself,  towards  the  fourteenth  year,  and  menstruation  is  re- 
peated at  determinate  periods.  Nature  appears  to  subject"  herself  in  all  her  acts,  to  cer- 
tain periods,  which  observation  may  ascertain,  without  any  possibility  of  arriving-  at  u 
knowledge  of  the  causes  of  these  phenomena  so  easy  to  establish.  Because  their  mani- 
festation is  corelative  to  certain  numerical  terms,  we  are  not  to  put  faith,  like  Py- 
thagoras, in  the  power  of  numbers,  and  believe  that  the  number  3  and  the  numbers  7 
and  9  enslave  all  nature  to  their  supreme  influence.  We  find  traces  of  this  ancient 
error  in  all  sciences,  in  all  religions,  even  in  those  of  enlightened  nations.— »#• 


422 

will  afterwards  become  the  first  large  grinders.  They  differ  from  those 
that  precede  them  in  this,  that  they  are  to  remain  all  life  long,  whilst  the 
primitive  or  milk  teeth  are  lost  at  seven  years  old,  in  the  same  order  in 
which  they  appeared,  and  are  replaced  by  new  teeth,  better  formed,  and 
larger,  excepting  the  small"  grinders,  and  with  longer  and  more  perfect 
roots.  Towards  the  ninth  year,  two  new  large  grinders  appear  beyond 
the  others.  The  child  has  then  twenty-eight  teeth,  and  dentition  is  com- 
plete; though  between  eighteen  and  thirty,  and  sometimes  much  later, 
the  dentes  sapientise,  two  to  each  jaw,  show  themselves  at  the  extremi- 
ties of  the  alveolar  processes. 

The  order  observed  in  the  successive  cutting  of  the  teeth  is  not  so  in- 
variable, but  it  is  frequently  inverted.  A  child  ten  years  old,  now  under 
my  care,  cut  the  four  first  small  grinders  before  the  canine  teeth.  Den- 
tition is  in  this,  respect,  like  all  other  acts  of  the  living  economy  :  insta- 
bility is  its  principal  character.  An  attentive  examination  soon  shows 
how  irregularly  those  phenomena  proceed,  whether  physiological  or  pa- 
thological, which  appear  the  most  to  be  subjected  to  calculable  and  de- 
terminate periods*. 

This  double  range  of  successive  teeth  existed  in  the  jaws  of  the  foetus. 
Each  alveolar  process,  at  that  age  of  life,  contains  two  membranous  folli- 
cles, lying  one  over  the  other.  That  which  is  to  form  the  primitive  tooth 
swells  the  first,  a  calcareous  matter  covers  its  surface  and  forms  the  body 
of  the  tooth,  which  invades  also  the  follicle  by  which  the  osseous  part  is 
secreted,  so  that  the  growth  of  the  little  bone  being  completed,  the  mem- 
branous vesicle,  in  the  parietes  of  which  the  dental  vessels  and  nerves 
branch  out,  is  found  in  the  centre  of  its  body,  and  adheres  to  the  parietes 
of  its  internal  cavity.  It  is  difficult  to  say,  why  the  growth  of  the  dental 
germs  is  successive  $  why,  in  the  seventh  year,  the  primitive  teeth  are 
detached,  and  are  replaced  by  others  which  have  remained  so  long  buried 
within  the  alveolar  processes.  Dentition  is  like  all  the  other  phenomena 
of  the  living  economy  ;  it  is  subject  to  endless  varieties  in  its  period  and 
duration,  &c.  Thus,  teeth  of  a  third  set  have  been  known  to  be  cut  iu 
very  old  people.  There  are  instances,  but  they  are  very  scarce,  of  chil- 
dren that  have  come  into  the  world  with  two  incisors  in  the  upper  jawfj 
there  are  often  supernumerary  teeth,  Sec. 

CCXXVI.  Ossification.  The  process  which  goes  on  in  the  osseous 
system,  is  not  confined  to  the  cutting  and  growth  of  the  little  bones  which 
are.  attached  to  the  two  jaw 9.^  AH  other  parts  of  the  skeleton  harden;  osse- 
ous nuclei  are  formed  in  the  centre  of  the  cartilages,  which  hold  the  place 
of  the  short  bones  of  the  carpus  and  tarsus  ;  the  thickness  of  the  cartila- 
ginods  substances,  which  separate  the  epiphyses  of  the  bodies  of  the 
long  bones,  is  diminished  ;-  the  large  bones  grow,  and  acquire  solidity, 
from  the  centre  to  the  circumference.  Those  of  the  skull  meet  at  their 
edges,  their  fibres  cross  and  form  the  sutures  5  the  cartilaginous  spaces, 


*  See  Erreurs  populaires,  sec  :  edit :  Chap.  4.  des  Jlnnees  climaleriquesy  et  des  Jours 
critiques  dans  les  maladies. 

f  Louis  XIV.  was  born  in  this  condition.  BAUDELOcauB  observes,  that  the  evolution 
of  some  teeth,  before  birth,  is  not  always  connected  with  an  extraordinary  growth  of 
the  infant;  nor  is  it  always  a  pressage  of  a  stronger  constitution.  He  endeavours  to 
prove  this  by  several  examples  :  these,  however,  may  be  regarded  as  exceptions  only 
from  the  general,  and,  we  think,  correct  opinion  on  the  subject.  For  some  remarks  on 
the  production  of  the  teeth,  see  APFKSDIX,  Note  KK 


423 

(fontanele)  which  were  situated  at  the  meeting  of  their  edges  and  angles, 
disappear.  The  urine  contains  exceedingly  little  phosphate  of  lime,  that 
salt  being  entirely  taken  up  in  the  solidification  of  the  bones.  About  the 
middle  of  the  second  year,  these  have  already  acquired  substance  and  so- 
lidity enough  to  support  the  weight  of  the  body;  the  child  can  stand 
and  walk.  Before  this  time,  it  would  be  dangerous  for  him  to  try  it  :  the 
pillars  of  support,  yet  too  flexible,  would  yield  under  the  burthen,  and 
bead  permanently  in  different  directions.  It  is  towards  the  bead,  that 
the  vital  motions  tend  in  infancy  :  accordingly,  this  part  is  the  principal 
seat  of  the  affections  peculiar  to  this  age,  affections  in  which  it  is  often  of 
use  to  procure  local  evacuations. 

The  organs  of  the  senses,  open  to  all  sorts  of  impressions,  receive  them 
with  ease  ;  but  if,  in  early  infancy,  sensation  is  easy,  it  is  very  transient: 
no  doubt  from  the  want  of  consistence  in  the  cerebral  organ.  As  it  grows 
older,  the  mobility  of  the  child  is  lessened,  without  diminution  of  suscep- 
tibility :  and  it  is  during  the  years  that  precede  the  boisterous  season  of 
puberty,  that  he  enjoys,  in  the  highest  degree,  the  faculty  of  recalling 
things  that  have  affected  him,  that  his  memory  is  most  distinct  and  ex- 
tended ;  but  soon  overpowered  by  imagination,  roused  up  by  the  power- 
ful reaction  of  the  sexual  organs  on  the  brain,  it  ceases  to  have  the  same 
exactness. 

CCXXVII.  Of  fiuberty.  Sex,  climate,  manner  of  life,  have  great  in- 
fluence on  the  earlier  or  later  manifestation  of  the  phenomena  of  puberty. 
Women  reach  it  one  or  two  years  before  men:  the  inhabitants  of  south- 
ern, long  before  those  of  northern  countries.  Thus,  in  the  hottest  cli- 
mates of  Africa,  Asia,  and  America,  girls  arrive  at  puberty  at  ten,  even 
at  nine  years  old,  but  in  France,  not  till  twelve,  fourteen,  or  fifteen  :  whilst 
in  Sweden,  Russia,  and  Denmark,  the  menstrual  discharge,  the  most  cha- 
racteristic mark  of  puberty,  is  from  two  to  three  years  later. 

The  male  is  known  to  be  capable  of  generation,  and  that  he  begins  to 
live  .the  life  of  the  species,  by  the  emission  of  prolific  semen,  and  the 
change  of  voice,  which  becomes  fuller,  more  grave,  and  sonorous;  the 
chin  becomes  covered  with  beard,  the  genitals  with  hair,  and  they  attain 
rapidly  their  full  size.  The  whole  body  grows  ;  the  general  characters 
which  distinguish  the  two  sexes,  and  which  are  so  obscure,  before  puberty, 
that  they  may  often  be  mistaken,  become  very  decided,  and  can  no  longer 
be  confounded. 

By  all  these  signs  of  strength  and  virility,  woman,  urged  by  desires 
which  may  be  termed  wants,  recognizes  the  being  capable  of  gratifying 
them.  The  change  of  voice  is  the  most  certain  of  the  indications  of  male 
puberty.  It  depends,  as  the  following  observations  show, on  the  de\ elope- 
ment of  the  vocal  organs,  which  constantly  accompanies  that  of  the  sexu- 
al parts. 

CCXXVIII.  A  boy,  aged  fourteen,  died  in  1799  at  the  Hospital  of  la 
Charite.  On  opening  the  larynx,  I  was  surprised  to  see  it  so  small ;  and 
especially  the  glottis,  which  was  not  above  five  lines  in  its  antero-posterior 
diameter,  and  about  a  line  and  a  half  in  its  transverse  diameter,  where  its 
dimensions  are  greatest;  an  observation  that  must  not  be  omitted,  is,  that 
he  was  very  tall :  but  that  the  developement  of  the  genital  organs  was  as 
backward  as  of  the  vocal.  I  have  repeated  the  same  observation  on  sub- 
jects further  from  the  age  of  puberty;  I  have  extended  my  researches  to 
ihose  who  had  passed  it,  and  I  have  obtained,  as  a  ;  cneral  result,  that 
between  the  larynx  and  the  glottis  of  a  child  of  three  or  of  twelve,  the 


424 

difference  of  size  is  very  inconsiderable,  and  cannot  be  estimated  by  the 
height  of  the  figure  :— 

That,  at  the  epoch  of  puberty,  the  organ  of  the  voice  enlarges  rapidly, 
and  that,  in  less  than  a  year,  the  opening  of  the  glottis  increases,  in  the 
propertion  of  five  to  ten,  that  its  extent  is  thus  doubled  both  in  length  and 
breadth. 

That  these  changes  are  less  remarkable  in  women,  whose  glottis  in- 
creases, in  the  proportion  only  of  about  five  to  seven:  that  in  this  respect 
they  still  resemble  children,  as  the  tone  of  their  voices  would  lead  us  to 
suppose. 

These  differences,  in  the  size  of  the  glottis,  account  for  the  danger  which, 
in  children,  accompanies  the  croup.  For,  suppose  an  opening  of  a  line 
and  a  half  in  width,  of  which  the  edges  are  covered  with  a  membrane  of 
coagulable  lymph,  the  opening  will  be  entirely  stopped  :  it  would  be  only 
narrowed,  if  its  width  were  double:  a  sufficient  space  would  remain  free 
from  the  passage  of  the  air.  This  supposition,  which  I  have  employed  to 
make  myself  understood,  is  only  the  expression  of  the  truth,  since  anato- 
mical inspection  shows  that  the  glottis,  in  adults,  is  double  the  size  it  is 
before  puberty. 

CCXX1X.  Menstruation.  The  symptoms  by  which  puberty  is  known, 
in  women,  are  not  less  remarkable.  The  swelling  of  the  genital  organs 
straightens  the  opening  of  the  canals  that  make  part  of  them.  The  breasts 
become  enlarged,  and  form,  at  the  fore  part  of  the  thorax,  marked  projec- 
tions. Further,  there  comes  on  a  discharge  (apparently)  of  blood,  which 
takes  place  every  month,  from  the  vessels  of  the  womb,  and  which  is  known 
by  the  name  of  the  menstrual  discharge,  or  menses.  This  periodical  eva- 
cuation declares  itself,  in  most  women, by  all  the  symptoms  that  indicate 
fulness  of  blood,  as  spontaneous  lassitude,  heat,  and  flushings  in  theface; 
and  by  others,  which  show  the  direction  of  the  humours  towards  the 
uterus,  and  a  local  plethora  of  that  organ,  as  pains  in  the  kidneys,  and  a 
certain  itching  of  the  party.  The  first  eruption  puts  an  end  to  this  state; 
•which,  in  many,  may  be  considered  as  real  disease.  A  pure  red  blood 
flows,  in  more  or  less  abundance,  for  some  days,  the  general  heaviness 
goes  off,  and  the  woman  feeh  herself  relieved. 

I  shall  not  now  speak  of  the  many  deviations  incident  to  the  menstrual 
discharge,  and  which  must  be  considered  as  real  diseases.  Thus,  the 
uterine  discharge  has  been  known  to  be  supplied,  by  bleeding  from  the 
nose,  haemoptysis,melaena,  and  sometimes  by  unusual  evacuations  of  blood 
from  the  eyes,  ears,  the  fore-finger,  from  ulcerated  surfaces  over  different 
parts  of  the  body. 

It  is  easily  conceived,  that  the  different  parts  of  the  sanguineous  system 
may  supply  each  other's  place,  and  that  the  bloody  secretion,  in  which 
menstruation  consists,  failing  en  the  internal  surface  of  the  uterus,  may 
be  carried  on  by  another  part  equally  provided  with  capillary  vessels;  but 
that  similar  deviations  may  take  place  for  the  fluids  secreted  by  the  con- 
glomerate glands,  as  urine,  bile,  saliva,  is  difficult  to  believe,  notwith- 
standing the  many  testimonies  and  authorities  that  may  be  brought  in 
support  of  this  opinion. 

The  fluids  are  not  in  existence,  before  the  work  of  secretion  ;  the  urine, 
retained  in  the  bladder  and  in  the  uterus,  the  bile  stopped  in  the  gall 
bladder  and  the  hepatic  ducts,  after  it  hus  been  prepared  by  the  peculiar 
action  of  the  liver,  may,  it  is  true,  from  absorption*  by  the  lymphatic  ves- 
sels, be  carried  into  the  blood,  and  product  there  a  diseased  urinary  or 


bilious  diathesis ;  occasion  an  irritation  and  derangement,  after  which,  the 
humour  of  the  cutaneous  perspiration,  and  of  the  sweat,  and  the  saliva 
itself,  will  exhibit  some  of  the  qualities  of  the  humour  retained,  and  in- 
troduced by  the  absorbents,  into  the  circulation.  The  blood,  contami- 
nated by  the  admixture  of  a  certain  quantity  of  urine,  may  purify  itself  by 
various  emumctories,  by  urinous  vomitings  and  sweats;  but  that  urine 
may,  like  the  menstrual  blood,  come  out  at  the  eyes,  theearsorthe  navel, 
except  in  case  of  urinary  umbilical  fistula;  that  one  whose  urinary  dis- 
charge, by  the  urethra,  is  not  interrupted,  may  spontaneously  vomit  it,  is 
what  no  man,  who  has  any  sound  notions  of  physiology,  will  believe;  and 
yet  it  is  related,  with  full  details,  in  a  late  work,  where  these  errors  are 
found,  in  the  midst  of  many  interesting  researches,  on  various  points  of 
physiological  chemistry.  I  have  seen  myself  the  woman,  whose  urine 
has  been  so  well  analysed  by  Dr.  Nysten,  when  the  clinical  professor  of 
medicine,  at  Paris,  obliged  her  to  submit  to  a  severe  but  necessary  exa- 
mination, and  I  am  astonished  that  well  informed  men  should  so  long; 
have  given  credit  to  such  gross  impostures.  The  reader  will,  I  hope, 
excuse  this-  long  digression,  for  the  sake  of  its  importance.  Literary 
criticism  is  now  carried  on  with  such  partiality,  that  no  journalist,  in 
praising  justly  what  is  praise-worthy  in  the  valuable  work  of  Dr.  Nysten, 
has  pointed  out  the  imposture  of  which  he  was  the  dupe. 

At  first  irregular,  the  menstrdal  discharge  assumes  regularity,  is  re- 
peated every  month,  and  lasts  from  two  days  to  a  week,  with  evacuation 
of  from  three  ounces  to  a  pound  of  fluid,  every  time.  Women  of  san- 
guine temperament,  robust  and  libidinous,  are  those  whose  menses  last 
longest,  and  flow  most  copiously.  The  fluid  is  of  an  arterial  red,  and  has 
not,  in  a  healthy  woman,  any  of  the  pernicious  qualities  which  have  been 
ascribed  to  it. 

During  the  whole  time  of  menstruation,  women  are  weaker,  more  deli- 
cate, more  susceptible  of  impressions;  all  their  organs  partake,  more  or 
less,  in  the  affection  of  the  uterus;  and  it  L'not  difficult  to  an  observer. 
of  any  practice,  to  discern,  the  state,  not  merely  by  the  state  of  the  pulse, 
but  by  the  change  ofv  countenance  and  tone  of  the  voice.  Women  then 
require  very  careful  management.  An  improper  blood-letting,  a  purge, 
or  any  other  remedy  untimely  administered,  may  suppress  the  discharge, 
and  occasion  the  most  serious  affections.  Climate  evidently  influences 
the  duration  and  quantity  of  the  discharge,  since  in  Africa,  it  flows  al- 
most continually,  whilst  in  Lapland,  it  takes  place  only  two  or  three  times 
a  year. 

I  shall  not  dwell  upon  the  different  explanations  that  have  been  given 
of  this  phenomenon.  Some  have  ascribed  it  to  the  oblique  position  of 
the  uterus,  without  considering,  that  upon  their  principal,  menstruation 
should  take  place  from  the  soles  of  the  feet.  Dr.  R.  Mead  believed 
that  it  depended  on  the  influence  of  the.  moon  over  the  female  system ; 
but  why  is  it  not  then  subjected  to  the  lunar  phases  ?  Those  who  have 
found  the  cause  of  it  in  plethora,  general  or  local,  if  we  admit  their 
explanation,  only  changed  the  difficulty;  for  then,  we  must  ask,  what  are 
the  causes  of  this  plethora?  But,  if  this  opinion  had  any  ground,  ner- 
vous women,  with  a  small  quantity  of  blood  in  their  system,  ought  not 
to  menstruate ;  and  yet  they  do  so  plentifully.  Must  we  ascribe  menstrua- 
tion to  an  acquired  hubit  ? 

Is  the  problem  resolved,  by  saying  that  all  the  secretory  organs  of  wo- 
men are  too  weak  to  evacuate  the  superfluitv  of  fluids,  which  would 


486 

require  for  them  a  new  emunctory  ?  Bat  is  not  this  taking  the  effect  for 
the  cause  ?  Does  not  this  smaller  quantity  of  fluids,  proceeding  from  the 
blood,  arise  from  the  purification  which  the  blood  undergoes  in  the  ute- 
rus ?  Let  it  be  remarked,  in  the  mean  time,  that  this  periodical  discharge 
seems  to  exempt  the  sex  from  many  inconveniences,  from  which  our's 
suffers  ;  such  as  gout,  stone  and  gravel,  so  unfrequent  with  them,  and  so 
common  with  us.  Nor  con  we  avoid  recognizing,  in  this  discharge,  a 
utility  relative  to  conception;  does  it  not  seem  to  dispose  the  uterus  to 
that  function*?  (CCIV.)  -  Was  it  not  requisite  that  this  organ  should  be 
accustomed  to  receive  a  great  quantity  of  blood,  that  pregnancy,  which 
calls  for  this  afflux,  might  not  be  injured,  by  bringing  on  a  sudden  cahnge 
in  the  system,  and  the  whole  of  the  vital  functions. 

Menstruation  is  suspended  during  pregnancy:  it  is  so  during  the  first 
month  of  suckling ;  though  this  rule  admits  of  many  exceptions.  Its 
cessation,  in  our  climate,  is  from  the  fortieth  to  the  fiftieth  year  £  some- 
times before,  seldom  later;  though  1  have  now  before  me  the  instance  of 
a  woman  of  seventy,  who  has  not  yet  ceased  jto  menstruate;  a  fact,  which, 
after  all,  is  nothing  more  surprising,  than  that  of  menstruation  beginning 
at  an  early  period  of  life.  When  menstruation  ceases,  the  breasts  col- 
lapse, plumpness  goes  off,  and  the  skin  shrivels,  and  loses  its  softness, 
colour,  and  suppleness.  This  cessation  is  the  cause  of  a  great  many  dis- 
eases which  break  out,  at  this  season  of  life,  called  the  turn  of  life,  and 
are  fatal  to  many  women;  but  then,  it  is  observed,  that  when  this  period 
is  past,  their  life  is  more  secure,  with  more  hope  of  prolonging  it  than  a 
man  has,  at  the  same  age. 

CCXXX.  Of  manhood.  To  youth  succeeds  manhood  :  which  may 
be  considered  as  beginning  from  the  twenty-first  to  the  twenty-fifth  year. 
Then,  all  increase  of  the  body,  in  height,  is  at  an  end.  The  processes 
are  completely  united  to  the  body  of  the  bones;  but  still,  growth  goes  on 
in  other  dimensions.  All  the  organs  acquire  remarkable  hardness,  so- 
lidity, and  consistency.  It  Is  the  same  with  the  intellectual  and  moral  fa- 
culties. To  the  empire  of  imagination,  succeeds  that  of  judgment. 
Man  is  capable  of  fulfilling  all  the  duties  of  family  and  society.  This 
period  of  life,  to  which  we  give  the  name  of  mature  age,  extends  to  the 
fiftieth  or  fifty-fifth  year  for  men:  it  scarcely  goes  beyond  the  forty-fifth 
for  women,  with  whom  it  begins  also  a  little  sooner.  During  this  long 
interval,  men  enjoy  the  whole  plentitude  of  their  existence. 

Although,  in  general,  it  is  not  difficult  to  distinguish,  at  first  sight, 
a  man  of  twenty-five,  from  one  of  fifty,  the  differences  which  mark  them, 
depending  on  the  quantity  and  colour  of  their  hair,  and  on  their  muscu- 
lar strength,  are  neither  many  nor  very  essential. 

Let  us  avail  ourselves  of  this  age,  during  which  the  characters  of  the 
human  species,  merely  sketched,  in  childhood  and  youth,  take  a  more 
defined  and  lasting  form,  to  trace  the  features  of  individuals  and  of 
races. 

CCXXXL  Of  temperaments  and  idiosyncrasies.  We  give  the  name 
of  temperaments  to  certain  moral  and  physical  differences  in  men,  which 
depend  on  the  various  proportions  and  relations  among  the  parts  that  make 
up  their  organization,  as  well  as  upon  different  degrees,  in  the  relative 

*  The  greater  part  of  the  female  quadrupeds  have  the  parts  of  generation  batbetl  in 
a  reddish  Jymph,  during1  the  time  of  being"  in  heat. — Author's  JVotev 


427 

energy  of  certain  organs,  "there  is>  besides,  in  each  individual,  a  mode 
of  existence  which  distinguishes  his  temperament  from  that  of  any  other, 
to  whom,  howe.ver,  he  may  bear  great  resemblance.  We  express  by  the 
term  idiosyncrasy^  these  individual  temperaments,  the  knowledge  of  which 
is  of  no  small  importance  in  the  practice  of  medicine. 

The  predominance  of  any  particular  system  of  organs,  modifies  the 
whole  economy,  impresses  striking  differences  on  the  results  or  the  or- 
ganization, and  has  no  less  influence  on  the  moral  and  intellectual,  than 
on  the  physical  faculties.  This  predominance  establishes  the  tempera- 
ment; it  is  the  cause,  and  constitutes  its  essence. 

If  the  heart  and  the  vessels  which  carry  the  blood  through  every  part, 
are  of  predominant  activity,  the  pulse  will  be  sharp,  frequent,  regular,  the 
complexion  ruddy,  the  countenance  animated,  the  shape  good,  the  forms 
softened  though  distinct,:  the  flesh  of  tolerable  consistence,  moderate 
plumpness,  the  hair  fair  and  inclining  to  chesnut ;  the  nervous  suscepti- 
bility will  be  lively,  and  attended  with  rapid  successfully,  that  is  to  say. 
that  being  easily  affected  by  the  impressions  of  outward  objects,  men  of 
this  temperament  will  pass  rapidly  from  one  idea  to  another;  conception 
will  be  quick,  memory  prompt,  the  imagination  lively;  they  will  be  ad- 
dicted to  the  pleasures  of  the  table  and  of  love  ;  will  enjoy  a  health  sel- 
dom interrupted  by  disease  5  and  all  their  diseases,  and  these  slight,  mo- 
dified by  the  temperament,  will  have  their  seat  principally  in  the  circula- 
tory system,  (inflammatory  fever,  or  angeiotenic  ;  jihlegmasia  ;  acute  hx- 
morrhage)  and  will  terminate,  when  moderate,  by  the  mere  force  of  nature, 
and  require  the  use  of  the  remedies,  called  antiphlogistic,  among  which, 
bleeding  is  the  chief.  The  ancients  applied  the  name  of  sanguine  to  this 
disposition  of  body;  they  considered  it  as  produced  by  the  combination 
of  warmth  and  moisture,  and  had  very  correctly  perceived  that  it  existed 
in  the  young  of  both  sexes,  was  heightened  by  the  spring,  the  season 
which  has  been  justly  compared  to  youth,  calling  that  age  the  spring 
time  of  life. 

That  the  specific  characters  of  the  temperament  I  have  just  described, 
may  show  themselves,  in  all  their  truth,  it  is  requisite  that  the  moderated 
developement  of  the  lymphatic  system,  coincide  with  the  energy  of  the 
sanguineous  system,  so  that  these  tv/o  sets  of  vascular  organs  may  be  in 
true  equipoise.  The  physical  traits  of  this  temperament  are  to  be  found 
in  the  statutes  of  Andnous  and  the  Apollo  of  Belvidere.  Its  moral  phy- 
siognomy is  drawn  in  the  lives  of  Mark  Antony  and  Alcibiades.  In  Bac- 
chus are  found  both  the  forms  and  the  character.  But  why  seek  amongst 
the  illustrious  men  of  antiquity,  or  among  its  gods,  the  model  of  the 
temperament  I  have  been  describing,  whilst  it  is  so  easy  to  find  it  among 
the  moderns  ?  No  one  in  my  opinion,  exhibits  a  more  perfect  type  of  it 
than  the  Marshal  Duke  of  Richelieu,  that  man,  so  amiable,  fortunate  and 
brave  in  war,  light  and  inconstant,  to  the  end  of  his  long  and  brilliant 
career*. 

Inconstancy  and  levity  are  in  fact,  the  chief  attribute  of  men  of  this 
temperament :  excessive  variety  appears  to  be,  to  them,  a  necessity  as 

*  See  his  Memoirs,  6  vols.  8vo.. 

Voltaire  has  painted  his  character,  with  superior  ability,  in  many  verses  addressed  to 
him. 

Rival  du  conquerant  de  1'Inde, 

Tu  bois  tu  plais,  tu  combats,  &c.        Author's  Note, 


428 

much  as  an  enjoyment:  good,  generous,  feeling,  quick,  impassionate,  de- 
licate in  love,  but  fickle,  disgust  in  them  follows  close  upon  enjoyment: 
meditating  desertion,  in  the  midst  of  the  most  intoxicating  caresses,  they 
make  their  escape  from  beauty,  at  the  very  moment  she  thought  to  have 
bound  them  by  indissoluble  chains*.  In  vain  he  whom  nature  has  endow- 
ed with  a  sanguine  temperament,  will  think  to  renounce  the  pleasures  of 
the  senses,  to  take  fixed  and  lasting  likings,  to  attain,  by  profound  medi- 
tation, to  the  most  abstract  truths;  mastered  by  physical  dispositions,  he 
will  be  for  ever  driven  back  to  the  pleasures  from  which  he  flies,  to  the 
inconstancy  which  is  his  lot;  more  fitted  to  the  brilliant  productions  of 
^vit,  than  the  sublime  conceptions  of  geniusf.  His  blood,  which  a  vast 
lung  impregnates,  plentifully,  with  atmospherical  oxygen,  flows  freely  in 
very  dilatable  canals,  and  this  facility  in  the  distribution  and  course  of 
the  fluid  is,  at  once  the  cause  and  the  image  of  the  happy  disposition 
of  his  mind. 

CCXXXU.  If  men  of  this  temperament  apply  themselves,  from  cir- 
cumstances, to  labours  which  greatly  exert  the  organs  of  motion,  the 
muscles,  plentifully  supplied  with  nourishment,  and  disposed  to  acquire 
a  developement  proportioned  to  that  of  the  sanguineous  system,  in- 
creases in  bulk:  the  sanguineous  temperament  undergoes  a  great  modi- 
fication; and  there  results  from  it,  the  muscular  or  athletic  temperament, 
conspicuous  by  all  the  Outward  signs  of  vigour  and  strength.  The  head 
is  very  small,  the  neck  sunk,  especially  backward,  the  shoulders  broad, 
the  chest  large,  the  haunches  solid,  the  intervals  cf  the  muscles  deeply 
marked. 

The  hands,  the  feet,-  the  knees,  all  the  articulations  not  covered  by 
mnscles,  seem  very  small,  the  tendons  are  marked  through  the  skin 
which  covers  them :  the  susceptibility  is  not  great :  feeling  dull  and  dif- 
ficult to- rouse,  the  athletic  surmounts  all  resistance,  when  he  has  broken 
from  his  habitual  tranquillity.  The  Farnese  Hercules  exhibits  the  model 
of  the  physical  attributes  of  this  particular  constitution  of  body;  and 
what  fabulous  antiquity  relates  of  the  exploits  of  this  demi-god,  gives  us 
the  idea  of  the  moral  dispositions  that  accompany  it.  In  the  history  of 
his  twelve  labours,  without  calculation,  without  reflection,  and  as  by  in- 
stinct, we  see  him  courageous,  because  he  is  strong,  seeking  obstacles 
to  conquer  them,  certain  of  overwhelming  whatever  resists  him;  but  join- 
ing to  such  strength  so  little  subtlety,  that  he  is  cheated  by  all  the  kings 
he  serves,  and  all  the  women  he  loves.  It  would  be  difficult  to  find,  in 
history,  the  example  of  a  man  who  has  combined,  with  the  physical 


*  The  history  of  Henry  IV.  of  Louis  XIV.  of  Regnard,  and  of  Miraberui,  proves  that, 
to  the  extreme  love  of  pleasure,  sanguine  men  join,  when  circumstances  require  it, 
great  elevation  of  thought  and  character;  and  can  bring  into  action  the  highest  talents 
In  every  department. 

•f- 1  have  just  met,  in  a  gazette,  with  an  assertion,  at  least  singular.  All  the  world 
knows,  says  the  journalist,  that  Newton  was  sanguine,  and  this  proves  clearly,  he  adds, 
that  temperaments  have  no  influence  on  the  intellectual  powers.  I  would  ask  the  jour- 
nalist, where  he  has  discovered  that  Newton  \va.s  sanguine.  The  few  details  which  bio- 
graphers have  preserved  on  the  physical  temperament  of  this  illustrious  philosopher, 
lead  us  to  believe  that  his  temperament  was  the  melancholic,  which  is  very  frequently 
met  with  in  England.  I  will  not  dare  to  pronounce  absolutely,  on  subjects  on  which  we 
can  attain  only  a  certain  degree-of  probability  ;  but  if  Newton  had  been  sanguine,  he 
would  not  have  gone  to  the  grave  at  the  age  of  fourscore,  never  having1  known  woman, 
as  it  is  afhrmed  lie  did. — Author's  Note. 


429 

powers  which  this  temperament  implies,  distinguished  strength  of  the 
intellectual  faculties.  For  excelling  in  the  fine  arts,  and  in  the  sciences, 
there  is  need  of  exquisite  sensibility,  a  condition  absolutely  at  variance 
with  much  developement  of  the  muscular  masses. 

CCXXXIII.  If  sensibility,  which  is  vivid  and  easily  excited,  can  dwell 
long-  upon  one  object:  if  the  pulse  is  strong,  hard,  and  frequent,  the  sub- 
cutaneous veins  prominent,  the  skin  of  a  brown*  inclining  towards  yel- 
low, the  hair  black,  moderate  fulness  of  flesh,  but  firm,  the  muscles  mark- 
ed, the  forms  harshly  expressed  ;  the  passions  will  be  violent,  the  move- 
ments of  the  soul  ofteri  abrupt  and  impetuous,  the  character  firm  and 
inflexible.  Bold  in  the  conception  of  a  project,  constant  and  indefatig- 
able in  its  execution,  it  is  among  men  of  this  temperament  we  find  those 
who  in  different  ages  have  governed  the  destinies  of  the  world :  full  of 
courage,  of  boldness,  and  activity,  all  have  signalized  themselves  by  great 
virtues,  or  great  crimes,  have  been  the  terror  or  admiration  of  the 
universe.  Such  were  Alexander  and  Julius  Caesar,  Brutus,  Mahomet, 
Charles  XII.  the  Czar  Peter,  Cromwell,  Sixtus  V.  Cardinal  Richelieu, 
and  Napoleon  the  Great. 

As  love  in  the  sanguine,  ambition  is  in  the  bilious  the  governing  pas- 
sion. Observe  a  man,  who,  born  of  an  obscure  family,  long  vegetates  in 
the  lower  ranks  :  great  shocks  agitate  and  overthrow  empires  :  at  first  a 
secondary  actor  in  these  great  revolutions  which  are  to  change  his  des- 
tiny, the  ambitious  man  hides  his  designs  from  all,  and  by  degrees,  raises 
himself  to  the  sovereign  power,  employing,  to  preserve  it,  the  same  ad- 
dress with  which  he  possessed  himself  of  it.  This  is,  in  two  words,  the 
history  of  Cromwell  and  of  all  usurpers*. 

To  attain  to  results  of  such  importance,  the  profoundest  dissimulation 
and  the  most  obstinate  constancy,  are  equally  necesssary ;  these  are, 
further,  the  most  eminent  qualities  of  the  bilious.  No  one  ever  combin- 
ed them  in  higher  perfection  than  that  famous  Pope,  who  slowly  travel- 
ling on  towards  the  pontificate,  went  for  twenty  years,  stooping  and  talk- 
ing, for  ever,  of  his  approaching  death,  and  who,  at  once,  proudly  rear- 
ing himself,  cries  out,  "  I  am  Popef  !"  petrifying  with  astonishment  and 
mortification,  those  \vhom  this  artifice  had  deceived  into  his  party. 

Such  too  was  Cardinal  Richelieu,  who  raised  himself  to  a  rank  so  near 
to  the  highest,  and  was  able  to  maintain  himself  in  it:  feared  by  a  King 
whose  authority  he  established,  hated  by  the  great,  whose  power  he  de- 
stroyed, haughty  and  implacable  towards  his  enemies,  ambitious  of  every 
sort  of  glory,  &cj . 

The  historians  of  the  time  inform  us,  that  this  celebrated  minister 
showed  all  the  customary  signs  of  the  bilious  temperament.  Gourvillc 
tells  us  that  he  was,  all  his  life  subject  to  a  very  troublesome  haemorrhoi- 
dal  discharge§. 

This  temperament  is  further  characterized  by  the  premature  develope- 
ment of  the  moral  faculties.  Scarcely  past  their  youth,  the  men  I  have 
named  projected  and  carried  into  execution  enterprizes  which  would  have 
been  sufficient  for  their  fame.  An  excessive  developement  of  the  liver,  a 

Vie  d'OHvicr  CiY>m\vcIl,  par  Jeuoy  Dugour,  2  vols.  18mo. 
y  Vie  tie  Sixte  Q-uintt  2  vols.  in  12mo. 

±  See  his  character  drawn,  with  as  much  truth  as  eloquence,  by  Thomas,  in  the  last 
edition  of  his  Es»ai  sur  les  Eloges. 
§  Memoirs  de  Gourvjlle- 


436 

remarkable  superabundance  of  the  biliary  juices,  most  commonly  acconr- 
pany ing  this  constitution  of  body,  in  which  the  vascular  sanguineous  system 
enjoys  the  greatest,  energy  to  the  prejudice  of  the  cellular  and  lymphatic 
system,  the  ancients  gave  it  the  name  of  bilious.  The  diseases  to  which 
those  distinguished  by  it  are  subject,  involve,  in  fact,  either  as  their  prin- 
cipal characteristic,  or  as  accessary  circumstances,  or  as  complication, 
the  derangement  of  the  action  of  the  hepatic  organs,  joined  to  changes 
of  composition  in  the  bile.  Among  the  remedies  directed  against  these 
sort  of  diseases,  evacuants,  and  especially  emetics,  are  the  best. 

Tf  all  the  characteristics  assigned  to  the  bilious  temperament  are  car- 
ried to  the  highest  degree  of  intensity,  and  to  this  state  is  added  great 
susceptibility,  men  are  irascible,  impetuous,  violent,  on  the  slightest  oc- 
casions. Such  Homer  describes  Achilles,  and  some  others  of  his 
heroes. 

CCXXX1V.  When,  to  the  bilious  temperament,  is  added  diseased 
obstruction  of  any  one  of  the  organs  of  the  abdomen,  or  derangement  of 
the  functions  of  the  nervous  system,  so  that  the  vhal  functions  are  feebly 
or  irregularly  performed,  the  skin  takes  a  deeper  hue,  the  look  becomes 
uneasy  and  gloomy,  the  bowels  sluggish,  all  the  excretions  difficult ; 
the  pulse  hard  and  habitually  contracted.  The  general  uneasiness 
affects  the  mind ;  the  imagination  becomes  gloomy,  the  disposition  sus- 
picious; the  exceedingly  multiplied  varieties  of  this  temperament  called 
by  the  ancients  the  melancholic^  the  diversity  of  accidents  that  may  bring  it 
on,  such  as  hereditary  disease?  long  grief,  excessive  study,  the  abuse  of 
pleasures,  &c.  justify  the  opinion  which  Glerc  has  proposed,  in  his  natural 
history  of  man,  in  a  state  qf  disease,  where  he  considers,  the  melancholic 
temperament  less  as  a  primitive  and  natural  constitution,  than  as  a  dis- 
eased affection  hereditary  or  acquired.  The  characters  of  Lewis  XL  and 
Tiberius,  leave  nothing  wanting  for  the  moral  determination  of  this  tem- 
perament. Read,  in  the  Memoirs  of  Philip  de  Commines,  and  in  the 
Annals  of  Tacitus,  the  history  of  these  two  tyrants,  fearful,  perfidious, 
mistrustful,  suspicious,  seeking  solitude  by  instinct,  and  polluting  it  by  all 
the  acts  of  the  most  savage  atrocity,  and  the  most  ungoverned  debauch. 
Distrust  and  fearfulness,  joined  to  all  the  disorders  of  imagination,  com- 
pose the  moral  character  of  this  temperament.  The  passage  in  which 
Tacitus  paints  the  artful  conduct  of  Tiberius,  when  he  refuses  the  em- 
pire, offered  him,  after  the  death  of  Augustus,  may  be  given  as  the  most 
perfect  model  of  it.  Fersse  inde  ad  Tiberiem  p. reces,  fyc.  Corn.  Tacit.  An- 
nal.  lib.  I. 

As  Professor  Pinel  very  justly  observes,  in  his  treatise  on  insanity,  the 
history  of  men  celebrated  in  the  sciences,  letters  and  arts,  has  shown  us 
the  melancholic  under  a  different  light :  endowed  with  exquisite  feeling, 
and  the  finest  perception  :  devoured  with  an  ardent  enthusiasm  for  the 
beautiful,  capable  of  realizing  it  in  rich  conceptions,  living  with  men  in 
a  state  of  reserve  bordering  upon  distrust,  analyzing  with  care  all  their 
actions,  catching  in  sentiment  its  most  delicate  shades,  but  ready  in  un- 
favourable interpretations,  and  seeing  all  things  through  the  dingy  glass 
of  melancholy. 

It  is  extremely  difficult  to  delineate  this  temperament  in  a  general  or 
abstract  manner.  Though  the  ground-work  of  the  picture  remains  al- 
ways the  same,  its  numerous  circumstances  give  room  for  an  infinite 
number  of  variations.  It  is  better,  therefore,  to  have  recourse  to  the  lives 
©f  illustrious  men,  who  have  exhibited  it  in  all  its  force.  Tasso,  Pascal, 


3T.  J.  Rousseau,  Gilbert,  Zimmerman,  are  remarkable,  among  many  others, 
and  deserve,  by  their  just  celebrity,  to  fix  our  consideration.  The  first, 
born  in  the  happy  climate  of  Italy,  proscribed  and  unhappy  from  his  child- 
hood, author,  at  twenty-two  years  old,  of  the  finest  epic  poem  the  moderns 
can  boast  of,  seized  in  the  midst  of  the  enjoyments  of  premature  glory, 
with  the  most  violent  and  most  inauspicious  love  for  the  sister  of  the  Duke 
of  Ferrara,  at  whose  court  he  lived  :  an  extravagant  passion,  which  was 
the  pretext  of  the  most  cruel  persecutions,  and  which  followed  him  to 
his  death;  this  took  place  towards  the  thirty-second  year  of  his  age, 
on  the  eve  of  a  triumphal  pomp  which  was  prepared  for  him  in  the 
capitol. 

The  author  of  the  Provincial  Letters,  and  of  the  Thoughts,  enjoying, 
like  Tasso,  a  premature  eelebrity,  almost  on  quitting  childhood,  was 
led  to  melancholy,  not  like  him  by  the  crosses  of  unhappy  love,  but,  by  a 
violent  and  overpowering  terror,  which  left,  in  his  imagination,  the  sight 
of  a  gulph  for  ever  open  at  his  side ;  an  illusion  which  left  him  only  at 
his  death,  eight  years  after  the  accident*. 

No  one  perhaps,  has  ever  shown  the  melancholic  temperament,  in  a 
higher  degree  of  energy,  than  the  philosopher  of  Geneva.  To  be  con- 
vinced of  it,  it  is  enough  to  read,  with  attention,  certain  passages  of  his 
immortal  works,  and  especially  the  two  last  parts  of  his  confessions,  and 
the  Reveries  in  the  solitary  walker  :  tormented  with  continual  distrusts, 
and  fears,  his  fruitful  imagination  represents  to  him  all  men  as  enemies. 
If  you  believe  him,  the  whole  human  race  is  in  league  to  do  him  mischief, 
u  kings  and  nations  have  consfiired  together  against  the  son  of  a  jwor  watch- 
maker ;"  children  and  invalids  are  brought  in  to  execute  these  dreadful 
plots.  But  let  us  leave  him  to  speak  for  himself,  the  most  eloquent 
and  most  unfortunate  man  of  the  eighteenth  century  :  u  Here  then  I  am, 
alone  upon  the  earth,  without  brother,  neighbour,  friend,  without  society 
but  myself ;  the  most  sociable  and  the  most  loving  of  men  has  been  pro- 
scribed by  them  with  unanimous  consent. "  Further  on  he  adds,  "Could 
J  believe  that  I  should  be  held,  without  the  smallest  doubt,  for  a  mon- 
ster, a  prisoner,  an  assassin,  that  I  should  become  the  horror  of  the  hu- 
man'race,  and  the  game  of  the  rabble ;  that  all  the  salutation  of  those  that 
passed  by  me,  would  be  to  spit  upon  me  5  that  a  whole  generation  would 
amuse  itself,  with  unanimous  consent,  in  burying  me  alive  ?"  It  is  idle 
to  multiply  quotations,  in  speaking  of  the  works  of  a  philosopher,  who, 
in  spite  of  his  errors,  will  ever  be  the  delight  of  all  those  who  love  to 
read  and  to  thinkf. 

The  history  of  J.  J.  Rousseau,  like  that  of  all  the  melancholies  who 
have  distinguished  themselves  in  literature,  shows  us  genius  struggling 
with  misfortune  ;  a  strong  soul  lodged  in  a  feeble  body,  at  first  gentle, 
affectionate,  open  and  tender,  soured  by  the  sense  of  an  unhappy  condi- 
tion, and  of  the  injustice  of  men.  Till  the  time  when,  impelled  by  the 
desire  of  fame,  Rousseau  sprang  forward  in  the  career  of  letters,  we  see 
him  endowed  with  a  sanguine  temperament,  acting  with  all  the  qualities 
belonging  to  it,  gentle,  loving,  generous,  feeling,  though  inconstant :  his 
fertile  imagination  shows  him  nothing  but  gay  images,  and,  in  this  illu- 


*  Blaise  Pascal  died  at  89.     See  his  life  by  Condorcet. 

f  Consult  the  Studies  of  Nature,  by  Betnardin  de  Saint  Pierre  ;  and  the  Letters  on 
J.  J.  Rousseau,  by  Madame  de  Stael. 


sion  of  happiness^  he  lives  on  agreeable  chimeras;  but  gradually  uncle* 
ceived  byjthe  hard  lessons  of  experience,  afflicted,  in  the  depth  of  his 
heart,  witfi  his  own  wretchedness  and  the  wrongs  of  his  fellow-creatures, 
•  his  bodily  vigour  wastes  and  decays,  with  it  his  moral  nature  changes, 
and  he  may  be  referred  to  as  the  most  striking  proof  of  the  reciprocal  in- 
fluence of  the  moral  on  the  physical,  and  the  physical  on  the  moral  part 
of  our  being*.  His  history  is  a  proof,  beyond  reply,  that  the  melancholic 
temperament  is  less  a  peculiar  constitution  of  the  body  than  a  real  dis- 
ease, of  which  the  degrees  may  infinitely  vary,  from  a  mere  originality 
of  character,  to  the  most  decided  munia. 

Gilbert  arrived  at  Paris,  with  the  germs  of  talents  fitted  for  that  great 
theatre.  Poor  and  rebuffed  by  those  on  whom  he  had  built  his  hopes,  he 
mixed  in  the  ranks  of  their  detractors,  and  soon  signalized  himself, 
among  the  most  formidable,  by  a  vigour  worthy  of  a  better  cause.  Per- 
secuted, without  respite,  by  want ;  the  mortifying  sight  of  the  happiness 
which  his  enemies  enjoyed,  and  to  which  he  believed  himself  called,  led 
him  on  to  a  state  of  perfect  madness.  He  believed  himself  persecuted  by 
the  philosophers,  who  wanted  to  rob  him  of  his  papers  :  to  save  them 
from  the  imagined  rapacity,  he  locked  his  manuscripts  in  a  press,  and 
swallowed  the  key.  It  stuck  at  the  entrance  of  the  larynx,  stopped 
the  passage  of  the  air,  and  suffocated  the  patient,  who  died,  at  the  Hotel- 
Dieu,  after  three  days  of  the  most  cruel  sufferingsf. 

Zimmerman,  early  exhausted  by  study,  already  a  physician  of  celebrity, 
at  an  early  age,  lived  in  solitude,  with  an  ardent  imagination  joined  to 
the  highest  susceptibility?  abandoned  to  himself,  devoured  with  the  thirst 
of  glory,  he  gave  himself  up  to  labour  in  excess,  published  his  treatise  on 


*  I  have  no  doubt  that  the  influence  of  the  physical  organization  on  the  intellectual 
faculties  is  so  decided,  that  we  may  regard  .as  possible  the  solution  of  the  following 
problem,  analogous  to  that  with  which  Condillae  concludes  his  work  on  the  origin  of 
human  knowledge. 

The  physical  man  being  given,  to  determine  the  character  and  extent  of  his  capacity,  and 
to  assign,  consequently:  not  only  the  talents  he  possesses,  but  those  he  is  capable  of  acquiring, 

The  profound  meditation  of  the  work  of  Galen  (guodanimi  mores  corporis  temper  amenta 
seqnantur  ,•)  the  perusal  of  Plutarch's  Lives  of  Illustrious  Men,  and  of  the  other  biogra- 
phers and  historians  of  ancient  and  modern  times;  of  the  Eulogies  of  Fontenelie,  Tho- 
mas, d'Alembert,  Condorcet,  Vicq-d'Axyr,  Sec.  and  the  study  of  the  medico-philosophi- 
cal works  of  Haller,  Cullen,  Cabanis,  Pinel,  Halle,  who  have  modified  and  enriched  the 
ancient  doctrine  of  temperaments,  will  be  of  great  avail  in  the  search  of  this  solution. 
"  Philosophy,"  cries  an  eloquent  writer,  in  the  noble  enthusiasm  which  seizes  him  at 
the  sight  of  the  riches  accumulated  by  Fontana,  in  the  Anatomical  Museum  in  Florence, 
**  Philosophy  has  been  in  the  wrong,  not  to  descend  more  deeply  into  physical  man  ; 
there  it  is  that  the  moral  man  lies  concealed;  the  outward  man  is  only  the  shell  of  the 
man  within. — (Dupaty,  33cl  Letter  on  Italy — Author's  Note. 

•j-  His  life  would  have  been  preserved,  if  the  cause  of  his  illness  had  been  understood, 
which  he  indicated  himself  by  repeating  frequently  "  the  key  chokes  me."  His  state  of 
madness  made  this  pass  for  the  words  of  a  madman;  but  on  opening  the  body,  they  key 
Mras  found,  of  which  the  ward  was  fixed  at  the  entrance  of  the  larynx  :  it  would  have 
been  easy,  to  draw  it  out,  by  putting  a  finger  down  the  throat. 

This  unfortunate  young  man  expressed,  a  few  days  before  his  death,  the  melancholy 
state  of  his  soul,  in  stanzas  most  touchingly  mournful :  this  is  one,  full  of  interest  and 
simplicity : 

Au  banquet  de  la  vie  infortune  convive, 

J'apparus  un  jour,  et  je  meurs  : 
Je  meurs  et  sur  ma  tombe  oulenteinent  j'arrivc 

Nul  ne  viendra  verser  cles  pleurs.  Jluitiv's  Note. 


433 

Experience,  and  the  work  on  Solitude,  so  deeply  imbued  with  the 
colouring  of  his  soul.  Forced  from  the  solitude  he  loved,  he  carried, 
into  the  courts  to  which  his  reputation  called  him,  in  an  exhaustible  store 
of  bitterness  and  sadness,  which  political  events  supervening  brought  to 
greater  excess  :  arrived,  at  length,  gradually  at  the  last  term  of  hypo- 
chondria* he  died  beset  with  pusillanimous  fears,  worthy  of  all  eulogium 
and  all  regret*. 

CCXXXV.  If  the  proportion  of  the  fluids  to  the  solids  is  too  great, 
this  superabundance  of  the  humours,  which  is  constantly  in  favour  of  the 
lymphatic  system,  gives  to  the  whole  body  considerable  bulk,  determined 
by  the  developement  and  repletion  of  the  cellular  tissue.  The  flesh  is 
soft,  the  countenance  pale,  the  hair  fair,  the  pulse  weak,  slow,  and  soft, 
the  forms  rounded  and  without  expression,  all  the  vital  actions  more  or 
less  languid,  the  memory  treacherous  the  attention  not  continuous.  Men 
of  this  temperament,  to  which  the  ancients  gave  the  name  of  pituitous, 
and  which  we  should  call  lymfihatic,,  because  it  depends  really  on  the  ex- 
cessive developement  of  this  system,  have,  in  general,  an  insurmountable 
inclination  to  sloth,  averse  like  to  labours  of  the  mind  and  body  :  accord- 
ingly, we  are  not  to  wonder,  if  we  find  none  of  them  among  Plutarch's 
Illustrious  Men.  Little  fitted  for  business,  they  have  never  exercised 
great  empire  over  their  fellow-creatures,  they  have  never  changed  the 
face  of  the  globe,  by  their  negotiations  or  their  conquests.  One  of  the 
friends  of  Cicero,  Pomponius  Atticus,  whose  history  Cornelius  Nepos 
has  left  us,  conciliating  to  himself  all  the  factions- which  tore  the  Roman 
republic  to  pieces,  in  the  civil  wars  of  Caesar  and  Pompey  may  be  given 
as  the  model  of  it. — Among  the  moderns,  the  easy  Michel  Montaigne, 
all  whose  passions  were  so  moderate,  who  reasoned  on  every  thing,  even 
on  feeling,  was  truly  pituitous.  But,  in  him,  the  predominance  of  the 
lymphatic  system  was  not  carried  so  far,  but  that  he  joined  it  to  a  good 
deal  of  nervous  susceptibility.  In  the  pituitous,  from  the  excess  of  wa- 
tery particles  in  the  fluid  which  should  carry  every  where  heat  and  life, 
the  circulation  goes  on  slowly,  the  imagination  is  weak,  the  passions 
languid;  and,  from  this  moderation  of  the  desires,  spring,  on  many  occa- 
sions, those  virtues  of  temperament,  which,  to  say  it,  by  the  bye,  should 
not  supply  their  possessors  with  matter  of  quite  so  much  self-com- 
placency. 

CCXXXVI.  This  property  by  which  we  are,  more  or  less,  sensible 
to  impressions  on  our  organs,  weak  in  the  pituitous,  almost  nothing  in 
athletes,  moderate  in  those  of  sanguine  temperament,  rather  quick  in  the 
billious,  constitutes,  by  excess,  nervous  temperament; — seldom  natural 
or  primitive,  but  commonly  acquired,  and  depending  on  a  sedentary  and 
too  inactive  life,  on  habitual  indulgence  in  sensuality,  on  a  morbid  action 
of  the  brain  promoted  by  reading  works  of  imagination,  8cc.  This  tem- 
perament shows  itself  in  the  emaciation,  in  the  smallness  of  the  muscles, 
soft,  and,  as  it  were,  in  an  atrophy,  in  the  vivacity  of  the  sensations,  in 
the  suddenness  and  mutability  of  the  determinations  and  judgments.— 
Nervous  women,  whose  wills  are  absolute  but  changeable,  with  excess  of 


*  See  his  Eulogium  by  Tissot ;  it  is  at  the  beginning  of  the  last  edition  of  the  Treatise 
on  Experience  in  Medicine.  It  there  appears  how  deeply  he  was  affected  by  the  French 
revolution,  of  which  he  foresaw,  with  a  sort  of  prophetic  spirit,  the  disastrous  conse- 
quences to  his  own  country.— Author's  Note. 

3  I 


434 

sensibility,  frequently  exhibit  it  with  all  these  characteristics.  Often? 
however,  they  have  something  of  good  looks,  the  extreme  preponderance 
of  the  nervous  system  still  allowing  a  moderate  developement  of  the  lym- 
phatic. Spasmodic  affections  are  not  uncommon  among  them  ;  and 
when  it  is  observed  that,  on  the  other  hand,  the  athletic  constitution,  di- 
rectly opposite  to  the  nervous  temperament,  predisposes  to  tetanus,  may 
we  not  say,  that  the  two  extremes  meet,  or  produce  the  same  effects? 

Anti-spasmodics  are  employed,  with  success,  in  the  treatment  of  their 
diseases,  which  partake  always,  more  or  less,  of  the  temperament.  Sti- 
mulants, on  the  contrary,  are  very  suitable  to  those  of  pituitous  or  lym- 
phatic temperament.  The  nervous  temperament,  like  the  melancholic, 
is  not  so  much  a  natural  constitution  of  the  body,  as  the  first  stage  of  a 
disease.  This  temperament,  like  the  nervous  affections  which  are  the 
result  of  it,  has  never  shown  itself  but  among  societies  brought  to  that 
state  of  civilization,  in  which  man  is  th€  farthest  possible  from  nature. 
The  Roman  ladies  became  subject  to  neivous  affections,  only  in  conse- 
quence of  those  depraved  manners  which  marked  the  decline  of  the  Em- 
pire. These  affections  were  extremely  common  in  France,  during  the 
eighteenth  century,  and  in  the  times  preceding  the  fall  of  the  monarchy. 
Of  that  epoch,  are  the  works  of  Whytt,  Raulin,  Lorry,  Pomme,  &c.  on" 
nervous  affections. — Tronchin,  a  Genevese  physician  acquired  great 
wealth  and  reputation  by  the  treatment  of  these  diseases.  His  whole  se- 
cret consisted  in  exercising  to  fatigue,  women  habitually  inactive,  keep- 
ing up  their  strength,  at  the  same  time,  by  simple,  healthy,  and  plentiful 
food.  The  two  most  remarkable  men  of  the  eighteenth  century,  Vol- 
taire and  the  great  Frederick,  may  be  given  as  instances  of  the  nervous 
temperament;  and  the  history  of  their  brilliant  and  agitated  life,  shows, 
sufficiently,  how  much  the  circumstances  in  which  they  lived,  contribu- 
ted to  develope  their  native  dispositions. 

I  shall  finish  this  article  on  temperaments  by  observing,  that  in  truth, 
we  bring  with  us  into  the  world  these  particular  dispositions  of  body:  but 
that  from  education,  manner  of  life,  climate,  acquired  habits,  they  are 
altered,  ov  altogether  changed.  Further,  it  is  exceedingly  rare  to  find 
individuals,  who  show,  in  their  purity,  the  characters  assigned  to  the 
different  temperaments:  the  descriptions  given  are  drawn  from  an  as- 
semblage of  individuals,  much  resembling  one  another.  Their  charac- 
ters are  pure  abstractions,  which  it  is  difficult  to  realize,  because  all  men 
are  at  once  sanguine  and  bilious,  sanguine  and  lymphatic,  Sec.  In  this 
instance,  physiologists  have  imitated  the  artist,  who  united  in  Che  image 
of  the  goddess  of  beauty,  a  thousand  perfections  which  he  saw  separate 
in-  the  most  beautiful  women  of  Greece*. 

It  is  an  observation  that  the  sanguine  constitution  is  directly  opposed 
to  the  melancholic,  and  never  combines  with  it ;  that  it  is  the  same  with 
the  bilious  and  lymphatic  :  though  it  may  happen  that  a  man  sanguine 
in  youth,  shall  become  melancholic  after  a  lapse  of  time :  for,  as  I  have 
said  before,  man  never  remains  such  as  he  came  from  the  hands  of  Na- 
ture ;  fashioned  by  all  that  surrounds  him,  his  physical  qualities,  at  dif- 
ferent periods  of  his  life,  are  as  much  changed  as  his  character. 


*  It  is  thus  that,  in  the  arts  of  imitation,  the  ideal  grows  up  ;  now,  from  the  exaggera- 
tion of  features,  now,  from  the  union  of  qualities  which  Nature  has  produced  separate. — 


435 

Of  all  the  causes  that  can  modify  the  nature  of  man,  and  which  will 
even  change  completely  the  nature  of  his  native  dispositions,  there  is 
none  more  powerful  than  the  long  continued  action  of  air,  water,  and  re- 
sidence, as  the  father  of  medicine  has  said.  Climate,  in  fact,  exerts  upon 
the  temperament  the  most  marked  influence.  Thus  the  bilious  tem- 
perament is  that  of  the  greater  part  of  the  inhabitants  of  southern 
countries;  the  sanguine  that  of  the  north;  the  lymphatic  constitution 
reigns,  on  the  contrary,  in  cold  and  moist  countries,  like  Holland.  We 
have  seen  in  what  manner  the  athletic,  melancholic,  and  nervous  tern- 
temperament  grows  out  of  our  habits  of  life :  let  us  now  endeavour  to 
appreciate  the  power  of  climate  over  the  constitution  of  the  greater  part 
of  mankind. 

It  is  known,  that  the  influence  of  heat,  in  the  production  of  bilious 
diseases,  is  such,  that  after  having  been  extremely  prevalent,  during  the 
summer,  they  disappear,  or  at  least  become  much  less  frequent  in  the 
autumn.  A  notable  increase  of  perspiration  never  takes  place,  without 
a  proportional  diminution  in  the  quantity  of  the  liquids  with  which  the 
alimentary  surfaces  are  moistened.  Now,  when  the  gastric  juice  is  less 
abundant,  the  bile,  being  mixed  with  a  smaller  quantity  of  serosities,  ir- 
ritates more  the  intestinal  surfaces;  the  digestive  powers  languish,  and 
there  is  an  approaching  disposition  to  meningo-gastric  fevers.  The 
same  influences,  continued  during  the  whole  year  in  hot  countries,  must 
necessarily  increase,  with  the  activity  of  the  biliary  system,  its  power 
over  the  other  parts  of  the  economy,  and  thus  establish  a  predominance 
of  the  bilious  constitution,  through  both  health  and  disease. 

As  for  the  sanguine  temperament,  so  generally  met  with  among  north- 
ern nations,  it  is  the  necessary  consequence  of  the  continual  and  very  en- 
ergetic re-action  of  the  powers  of  circulation,  against  the  effects  of  exter- 
nal cold.  It  is  only  by  the  constant  activity  of  the  heart  and  vessels,  that 
calorification  can  be  effected  with  the  necessary  vigour.  Now,  the  effects 
of  this  redoubled  action  are  the  same  to  the  organs  of  circulation,  as  to 
the  muscles  under  the  influence  of  volition  :  in  both,  exertion  increases 
the  power  of  the  organs  exerted.  The  diseases  of  the  nations  of  the 
north,  analagous  to  their  temperament,  have,  for  the  most  part,  their  seat 
in  the  system  of  sanguineous  vessels  :  their  character  is  eminently  inflam- 
matory. 

Lastly,  the  lymphatic  state  of  nations,  living  under  a  moist  climate,  is 
nothing  more  surprising  than  the  aqueous  nature  of  plants,  and  small 
density  of  the  wood,  in  trees  growing  under  the  influence  of  a  foggy  air. 
Animal  bodies,  like  plants,  absorb  by  their  surfaces,  and  become  gorged 
with  humours,  the  excess  of  which  always  produces  a  remarkable  slack- 
ening of  activity  in  the  organic  motions. 

The  temperament  of  which  the  character  is  the  predominance  of  one 
organ  or  system  of  organs,  departs  from  that  ideal  state,  where  all  the 
powers  are  reciprocally  balanced,  so  as  to  exhibit  in  the  living  economy  a 
perfect  equilibrium.  This  state,  which  has  perhaps  never  been  found 
but  in  the  imaginations  of  physiologists  and  which  was  called  by  the  an- 
cients the  temperate  temperament,  temperamentum  temperatum^  being' 
taken  as  the  type  of  health,  it  follows  that  this  temperament  is  already  a 
step  made  towards  disease.  Yet  the  action  of  the  predominant  system  is 
not  in  such  excess  as  to  destroy  all  equilibrium,  and  impede  the  action  of 
life;  but  let  the  constitutional  dispositions  be  much  increased,  the  dis- 
ease is  begun,  and  this  transition  takes  place  in  the  conversion  of  the 


lymphatic  temperament  into  scrophula*.  In  the  scropliulous  constitu- 
tion, there  is,  at  once,  activity  of  the  absorbing  mouths,  great  facility  of 
absorption,  inertness  of  the  vessels  and  lymphatic  glands,  weakness  of  the 
absorbents,  and  consequently  a  thickening  and  stagnation  of  the  liquids 
absorbed.  The  same  thing  is  seen  in  the  lymphatic  temperament,  cha- 
racterized by  the  activity  of  the  inhaling  mouths,  and  the  debility  of  the 
lymphatic  system,  as  Professor  Cabanis  was  awaref,  when  he  refuted  the 
opinion  of  those  who  ascribe  the  lymphatic  temperament  to  the  excess  of 
activity  in  the  absorbent  system,  though  the  only  part  of  this  system  re- 
ally quickened,  is  that  which  immediately  performs  absorption,  whilst 
the  rest  is  in  a  state  of  perfect  atony. 

CCXXXVIL  Varieties  of  the  human  species.  The  power  of  producing, 
by  copulation,  individuals  which  are  alike,  is  considered  by  naturalists  as 
the  most  certain  test  for  fixing  the  species  in  red  and  warm-blooded  ani- 
mals. This  power  of  self-perpetuation,  by  a  constant  succession  of  simi- 
lar beings,  is  found  in  all  the  races  composing  the  human  species,  how- 
ever different  in  colour,. structure,  and  manner  of  life.  Men,  then,  are 
but  one  species,  and  the  difference  that  appears  in  them,  according  to  the 
region  of  the  globe  they  inhabit,  can  only  constitute  varietes  or  races.  I 
admit,  with  Mr.  Lacepede,  the  worthy  continuator  of  Buffbn  four  principal 
races  of  the  human  species,  which  I  shall  call,  like  him,  the  European  Arab, 
the  Mogul,  the  Negro,  and  the  Hyperborean.  We  might  add  a  fifth,  of  the 
American,  were  it  not  most  probable,  that  the  new  Continent  is  peopled 
by  inhabitants,  who,  coming  from  the  old,  either  by  land  in  the  austral 
hemisphere,  or  along  the  immense  Archipelago  of  the  Pacific  Ocean, 
have  been  altered  by  the  influence  of  that  climate,  and  the  yet  virgin  soil, 
so  that  they  are  to  be  regarded  less  as  a  distinct  race  than  a  simple  va- 
rietyj. 

There  is,  in  truth,  this  difference  between  varieties  and  races,  that,  in 
these  last,  there  are  implied  modifications  more  profound,  more  essential 
differences,  changes  not  confined  to  the  surface,  but  extending  to  the  very 
structure  of  the  body  ;  whereas,  to  make  a  variety,  nothing  more  is  need- 
ed, than  the  superficial  influence  of  climate  on  the  integuments  which  it 
colours,  and  on  the  hairs  which  it  makes  longer  or  shorter,  lank  or  curl- 
ed, hard  or  soft.  An  Abyssinian,  scorched  by  the  heat  of  an  almost  tro- 
pical sky,  is  as  black  as  the  negro  under  the  equator?  yet  they  are  by  no 
means  of  one  race,  since  the  Abyssinian,  a  negro  only  in  colour,  resem- 
bles the  European  in  the  cast  of  his  face,  and  the  proportions  of  all  his 
parts. 

The  characteristics  of  the  European  Arab  race,  which  takes  in  the  in- 
habitants, not  of  Europe  only,  but  of  Egypt  also,  Arabia,  Syria,  Barbary, 
and  Ethiopia,  are  an  oval,  or  almost  oval  face,  in  the  vertical  direction,  a 
long  nose,  a  prominent  skull,  long  and  commonly  lank  hair,  a  skin  more 
or  less  white.  These  fundamental  characteristics  are  no  where  more 
decided  than  in  the  north  of  Europe-  The  inhabitants  of  Sweden, 
Finland,  and  Poland,  give  the  prototype  of  the  race:  their  .stature  is  tall, 

*  See  Nosographie  C/iirurgical,  tome  I.  for  the   history  of  scrophulous  ulcers,  from 
which  this  paragraph  is  taken  entire.     The  author,  in  that  work,  has  aimed  at  introdu- 
cing1 physiology  into  surgery,  till  then  exclusively  abandoned  to  explanations  of  the 
grossest  mechanism. — Jiutho^s  Note. 

|  Of  the  relations  of  the  physical  and  moral  man,  by  G.  Cabanis,  Senator,  Professor 
in  the  Scnool  of  Medicine  in  Paris,  £.c. 

*  See  APPENDIX,  Note  L  L. 


their  skin  of  perfect  whiteness,  their  hair  long,  lank,  and  of  a  light  co- 
lour of  the  iris  generally  bluish.  The  Russians,  the  English,  the  Danes, 
the  Germans,  are  already  removed  somewhat  from  this  primordial  type: 
the  colour  of  their  skiu  is  of  less  pure  white,  their  hair  of  a  deeper  hue. 
The  French  seem  to  stand  midway  betwixt  the  nations  of  the  north,  and 
those  of  the  south  of  Europe.  Their  skin  is  shaded  with  a  deeper  dye, 
their  hair  less  straight,  and  more  of  a  chesnut  and  brown  colour.  The 
Spaniards,  the  Italians,  the  Greeks,  the  European  Turks,  and  the  Portu- 
guese, are  browner,  their  hair  in  general  black.  Lastly,  the  Arabs,  the 
Moors,  and  the  Abyssinians  have  hair,  in  som-e  measure,  black  and  crisp, 
the  skin  tawny,  and  might  serve  for  the  step  from  the  European  Arab  to 
the  Negro  race;  which  is,  however,  distinguished  from  them  by  the 
flattening  of  the  forehead,  the  smallrtess  of  the  skull,  the  slope  of  the  line 
measuring  the  height  of  the  face,  the  thickness  of  the  lips,  the  projec- 
tion of  the  rnalar  bones,  and  further,  by  a  darker  skin,  thicker,  greasy, 
and,  as  it  were,  oily,  as  well  as  by  shorter,  finer,  curly,  and  wooly  hair. 

The  Mogul  race  has  the  forehead  flat,  the  skull  jutting  but  little,  the 
eyes  looking  rather  obliquely  outwards;  the  cheeks  are  prominent,  and 
the  oval  of  the  face,  instead  of  extending  from  the  forehead  to  the  chin, 
is  drawn  between  the  two  malar  bones.  The  Chinese,  the  Tartars,  the 
inhabitants  of  the  Peninsula,  of  the  Ganges,  and  of  the  other  countries 
of  India,  of  Tonquin,  Cochin-China,  Japan,  of  the  kingdom  of  Siam, 
&c.  compose  this  race,  which  is  more  numerous  than  all  the  others,  and 
apparently  more  ancient  also,  which  is  spread  over  a  greater  extent  of 
Surface  than  the  European  Arab  race,  and  yet  greater  than  the  Negro 
race,  since  it  reaches  from  the  fortieth  to  the  sixtieth  parallel  of  latitude, 
occupying  an  arc  of  the  meridian  of  nearly  75°,  whilst  that  which  mea- 
sures the  countries  of  the  European  race  is  only  of  50°,  and  the  Negro 
race  lying  under  the  equator,  between  the  tropics  of  Cancer  and  of 
Capricorn,  is  bounded  within  the  limits  of  an  arc  of  from  30°  to 
35°*. 

The  Hyperborean  race,  situated  in  the  north  of  the  two  continents,  in 
the  neighbourhood  of  the  polar  circles,  composed  of  the  Laplanders, 
the  Ostiaks,  the  Samoiedes,  and  the  Greenlanders,  is  characterized  by 
a  flat  face,  a  squat  body,  and  a  very  short  stature.  This  degraded  por- 
tion of  the  human  species  derives,  evidently,  from  the  climate,  its  dis- 
tinctive characteristics.  Striving  for  ever  with  the  inclemency  of  a  se- 
vere climate,  the  destructive  action  of  an  icy  temperature,  Nature,  fet- 
tered in  her  motions,  shrunk  in  her  dimensions,  can  produce  only  beings 
whose  physical  imperfections  explain  their  almost  barbarous  condition. 

The  small  progress  of  the  negroes  in  the  study  of  the  sciences,  and 
in  civilization,  their  decided  taste,  and  singular  aptitude  for  all  the  arts 
which  require  more  taste  and  dexterity  than  understanding  and  reflec- 
tion, as  dancing,  music,  fencing,  Sec.  the  figure  of  the  head,  which  is 
midway  between  that  of  the  European  and  the  ourang-outangf,  the  ex- 


*  Lacepede,  Geographic  Zoologique. 

f  The  black  colour  of  the  skin  in  the  negroes  seems  owing,  as  I  have  already  said, 
to  the  scorching-  of  the  gelatine,  which  is  the  base  of  the  rete  mucosum  of  Malpighi. 
This  colour,  acquired  in  a  long  succession  of  ages,  perpetuated  and  transmitted  by  ge- 
neration, is  become  one  of  the  characteristic  features  of  the  Negro  race.  M.  Volney, 
in  a  work  which  should  be  a  model  to  all  travellers,  grounds  on  the  face  of  the  blacks, 
a  conjecture  as  ingenious  as  it  is  probable.  He  observes,  that  it  exhibits  pre- 


438 

istence  of  the  intermaxillary  bones,  at  an  age  when,  with  us,  the  traces 
of  their  separation  are  completely  effaced ;  the  high  situation  and  small 
drvelopement  of  the  calf  of  the  leg,  have  been  arguments  more  specious 
than  solid  to  those  who  have  endeavoured  to  abase  this  portion  of  the 
>*uman  species,  in  order  to  justify  an  iniquitous  traffic,  and  a  cruel  ty- 
ranny; reproaches  of  civilized  men,  which  they  must  wipe  off  by  other 
means  than  a  presumptuous  assertion  of  their  own  dignity,  or  a  proud 
insult  on  the  native  character  of  those  whom  they  themselves  have  cast 
into  degradation. 

Without  admitting  this  belief,  which  owes  its  origin  to  a  thirst  of 
riches,  we  cannot  help  acknowledging  that  the  differences  of  organi- 
zation draw  after  them'  a  striking  inequality  in  the  devclopement  of  the 
moral  and  intellectual  faculties.  This  truth  would  appear  in  its  full 
light,  if,  after  summarily  indicating,  as  I  have  just  done,  the  physical 
characteristics  of  the  races  of  men,  I  could  unfold  their  moral  differences 
as  real,  and  not  less  marked:  opposing  the  activity,  the  versatility,  the 
restlessness  of  the  European,  to  the  indolence,  the  phlegm,  the  patience 
of  the  Asiatic,  examining  what  is  the  power,  or  the  character  of  nations, 
the  fertility  of  soil,  serenity  of  sky,  mildness  of  climate;  showing  by 
what  catenation  of  physical  and  moral  causes,  the  empire  of  custom  is 
so  powerful  over  the  people  of  the  east,  that  we  find  in  India  and  China 
the  same  laws,  manners,  and  religion,  which  prevailed  there  long  before 
our  era;  inquiring  by  what  singularity,  well  worthy  the  meditation  of 
philosophers  and  politicians,  these  laws,  this  worship,  and  these  man- 
ners, have  undergone  no  change,  amidst  the  revolutions  which  have  so 
often  taken  place  among  those  nations  many  times  conquered  by  the  war- 
like Tartars;  showing  how,  by  the  irresistible  ascendancy  of  wisdom  and 
knowledge,  ignorant  and  ferocious  conquerors  have  adopted  the  usages 
of  the  nations  they  have  subjugated;  and  proving  that  the  stationary 
condition  of  the  sciences  and  arts  among  those  who,  so  long  before  our- 
selves, were  in  possession  of  the  advantages  of  civilized  society,  is  deri- 
ved not  so  much  from  the  imperfection  of  thier  organization,  as  from  the 
degrading  yoke  of  a  religion  loaded  with  absurd  practices,  and  which 
makes  knowledge  the  exclusive  birth-right  of  a  privileged  cast*.  But 
such  an  undertaking,  besides  exceeding  the  limits  I  have  prescribed  my- 
self, does  not  belong  directly  to  my  subject. 

The  JHbinoes  of  Africa,  the  Cagots  of  the  Pyrenees,  and  the  Cretins  of 
the  Valais,  cannot  be  given  as  varieties  of  the  human  species.  They 


cisely  that  state  of  contraction  which  OUP  face  takes  when  it  is  struck  by  light,  and  a 
strong1  reverberation  of  heat ;  then,  says  this  philosophical  traveller,  the  brow  contracts, 
the  cheek-bones  rise,  the  eye-lids  contract,  and  the  lips  project.  Must  not  this  contrac- 
tion of  the  moveable  part  have  influenced,  in  course  of  time,  the  hard  parts,  and  even 
moulded  the  structure  of  the  bones  ?  Voyage  en  Syrie  ct  en  Egyptt  torn.  I.  p.  70.  Sieme 
Edition. — Jlnlhor's  Note. 

*  \Ve  must  assign  further  as  a  main  cause  of  the  want  of  progress  of  the  Indians  and 
Chinese,  in  the  arts  and  sciences,  sprung  from  civilization,  the  imperfection  of  their  al- 
phabet, which,  being  composed  of  a  multitude  of  characters,  which  do  not,  like  ours, 
represent  sounds,  but  ideas.  It  belongs  not  to  our  subject  to  show,  how  much  signs 
so  defective  must  confine  the  sphere,  and  fetter  the  combinations  of  the  mind. 

See,  concerning  the  religion  of  the  Bramins,  and  the  Indian  customs,  Raynal's  Phi- 
losophical  History  :  the  Asiatic  Researches;  Institutes  of  Menu,  Edin.  Review,  xxxii. ; 
Ward's  View  of  "the  History  of  the  Hindoos  :  Halked's  Code  of  Gentoo  Laws ;  Cole, 
brook's  Digest  of  Hindoo  Law. 


439 

are  infirm,  feeble,  degraded  beings,  incapable  of  re-producing  an  exist- 
ence, which  has  fallen  to  them,  in  the  midst  of  a  healthy,  vigorous,  and 
robust  population. 

We  are  not  to  believe  what  some  travellers  have  written  on  the  exis- 
tence of  tribes  of  giants,  that  have  appeared  on  the  Magellanic  coast. 
The  Patagonians,  concerning  whose  stature  there  is  so  little  agreement 
in  relations,  are  men  very  well  formed,  and  whose  stature  does  not  ex- 
ceed ours  more  than  nine  or  ten  inches.  The  Laplanders,  whose  stature 
is  the  smallest,  are  as  much  below,  as  the  Patagonians  are  above ;  it 
does  not  exceed  from  four  feet  to  four  and  a  half.  In  the  midst  of  our- 
selves, individuals  reach  from  time  to  time,  a  stature  sufficient  to  entitle 
them  to  the  name  of  gaints,  whilst  others,  shrunk  in  all  their  propor- 
tions, are  a  renewal  of  the  pymies.  Such  was  Bebe,  the  dwarf  of  Stan- 
islaus, king  of  Poland;  Goliah,  spoken  of  in  the  book  of  Kings,  chap, 
xvii.  v.  4;  the  king  Og,  Deut.  chap.  iii.  v.  2;  and  many  others,  whose 
stature  varies  from  six  to  ten  feet  high. 

CCXXXVIII.  Of  old  age  and  decrepitude.  The  human  body,  which, 
from  the  twentieth  year  of  life,  ceases  to  grow  in  height,  increases  in 
every  dimension  during  the  twenty  succeeding  years.  After  this  period, 
far  from  growing,  it  begins  to  decay, and  loses  daily  a  part  of  its  strength. 
The  decay  proceeds  at  the  same  rate  as  the  growth,  and  is  not  more  ra- 
pid, since  man  requires  from  thirty  to  forty  years  in  reaching  to  his  full 
growth,  and  takes  about  the  same  time  in  his  progress  to  the  grave,  pro- 
vided no  accident  hurries  him  to  an  untimely  end*.  The  whole  bulk  of 
the  body  diminishes!,  the  cellular  tissue  becomes  collapsed,  and  the  skin 
wrinkled,  especially  that  of  the  forehead  and  face.  The  hairs  of  the 
head  and  over  the  rest  of  the  body  turns  gray,  then  white;  the  organic 
action  becomes  languid;  the  fluids  become  more  disposed  to  putrefaction 
(Hunter;)  hence,  at  this  period  of  life,  all  diseases  of  debility  are  more 
frequent,  and  attended >with  greater  danger. 

Decay  succeeds  old  age.  The  sensibility  of  the  organs  is  blunted;  the 
physical  and  intellectual  faculties  undergo  a  gradual  decay;  man  ceases 


*  The  duration  of  life  may  be  estimated  by  that  of  the  growth.  A  dog  ceases  to 
grow  at  the  end  of  two  or  three  years,  and  lives  only  ten  or  twelve  ;  man,  whose 
growth  requires  a  space  of  from  twenty  to  thirty  years,  attains  to  the  age  of  ninety  or 
a  hundred.  Fishes  live  several  centuries,  their  developement  requiring-  a  considerable 
number  of  years — Author's  Note. 

•f-  The  diminution  of  the  entire  bulk  of  the  body  of  aged  persons  frequently  gives 
place  to  an  augmentation  of  size,  especially  of  the  trunk  of  the  body.  This  is  en- 
tirely  owing  to  the  increased  deposit  of  fat,  which  often  supervenes  at  this  age,  and 
which  appears  to  depend  on  the  energy  of  the  system  being  insufficient  to  the  com- 
plete assimilation  of  the  nutritive  materials,  and  on  the  slow  circulation  of  the  blood  in 
the  capillary  vessels,  which  state  of  the  circulation  seems  to  give  rise  to  the  predomi- 
nence  of  hydrogen  and  carbon  in  the  blood  which  these  vessels  and  the  ve.ns  contain. 
The  abundance  of  these  elements  in  the  extreme  vessels  being  the  source  whence  the 
fat  is  so  largely  formed,  the  combination  of  them  into  that  particular  substance  is  the 
result  of  the  same  state  of  the  vital  energies  which  favours  their  predominance.  The 
increase  of  bulk,  owing  to  this  augmentation  of  the  secretion  of  fat,  in  persons  ad- 
vanced in  life,  is  far  from  being  favourable  to  the  free  exercise  of  the  various  functions  ; 
for  certain  organs  being  incommoded  with  the  weight  and  bulk  which  they  thus  ac- 
quire, are  still  further  embarrassed  in  their  organic  movements,  the  circulation  in  the 
extreme  vessels  is  rendered  still  slower,  and  thus  the  cause  of  the  increased  secretion 
of  fat  goes  on  increasing.  This  sufficiently  accounts  for  the  fact,  that,  in  general,  lean^ 
ness  is  at  an  advanced  age  more  favourable  to  long  life,  than  the  opposite  state, 


440 

to  be  impressed,  in  the  same  manner,  by  surrounding  bodies.  His  judg- 
ments are  incorrect,  because  self-love  preventing  him  from  being  aware 
of  the  changes  which  he  lias  undergone,  he  is  more  disposed  to  ascribe 
to  a  universal  degeneracy,  the  difference  which  exists  between  the  sensa- 
tions which  he  now  experiences,-  and  those  which  he  experienced  in  his 
youth,  (laudator  temporis  acti.)  The  digestion  is  bad,  the  pulse  weak 
and  slow;  the  absorption  difficult,  from  the  almost  complete  obliteration 
of  the  lymphatics  and  the  induration  of  the  conglobate  glands;  the  lan- 
guid secretion  and  imperfect  nutrition.  The  old  man  is  slow  in  all  his 
actions,  and  stiff  in  all  his  motions;  his  hair  falls  off,  his  teeth  drop  from 
their  sockets;  the  cartilages  ossify;  the  bones  grow  irregularly  and  be- 
come anchylosed,  their  internal  cavity  enlarges;  all  the  organs  become 
indurated,  and  the  fibres  dried  and  shrivelled.  The  bones  become  heavier, 
from  the  gradual  accumulation  of  phosphate  of  lime,  and  if  those  of  the 
skull,  as  is  justly  observed  by  Soemmering,  on  the  contrary,  become 
lighter,  it  is  that  they  are,  in  a  manner,  worn  out. 

The  ossification  of  some  of  the  cartilages,  for  example,  those  of  the 
ribs  and  vertebrae,  is  productive  of  remarkable  effects.  The  ribs  be- 
coming soldered,  in  a  manner,  to  the  sternum,  perform  very  imperfectly 
their  natural  motion  of  elevation  and  twisting,  (LXXI.)  which  produces 
the  enlargement  of  the  chest.  This  cavity  dilating1  less  fully,  the  pulmo- 
nary combinations,  which  are  the  abundant  sources  of  animal  heat,  take 
place  in  a  less  effectual  manner,  which,  joined  to  a  want  of  tone  and 
energy  in  the  lungs,  and  in  all  the  organs,  lowers  the  temperature  of  old 
people,  as  was  observed  by  the  father  of  physic*,  a  circumstance,  how- 
ever, which  has  been  denied  by  Dehaen. 

Those  fibre-cartilaginous  lamina,  -with  oblique  fibres  crossing  each 
other,  which  unite  so  firmly  the  bodies  of  the  vertebrae,  become  indu- 
rated, dried,  and  shrivelled,  sink  under  the  weight  of  the  body,  and  do 
not  recover  their  former  thickness,  so  that  the  stature  is  really  reduced ; 
besides,  the  weakened  condition  of  the  muscles  which  raise  the  trunk, 
makes  the  weight  of  the  viscera  bend  forward  the  vertebral  column, 
whose  different  parts  may  remain  fixed  in  this  attitude,  so  that  the  whole 
column,  consisting  of  twenty-four  vertebrae,  may  come  to  consist  of 
only  seven  or  eight  distinct  bones.  It  should  not  be  imagined,  however, 
that  all  the  soft  parts  become  more  compact,  for  several,  as  Haller  ob- 
serves, the  muscles,  for  instance,  become  softerf,  and  seem,  in  losing 
a  part  of  their  vital  properties,  to  draw  towards  a  speedy  dissolution; 
not  that  death  is  entirely  owing  to  the  accumulation  of  phosphate  of 
lime,  which  enters  into  the  composition  of  all  the  organs,  converts  into 
ossific  matter  the  whole  osseous  system,  and  interrupts  the  action  of  the 
animal  machine.  If  this  ossific  matter  invade  every  part  of  the  animal 
system,  it  is  because  the  digestive  powers,  gradually  weakened,  cease  to 
affect,  in  a  suitable  manner,  the  alimentary  substances.  The  exuberance 
of  calcareous  salts,  is,  therefore,  not  so  much  the  cause  as  the  effect  of 
the  successive  destruction  of  the  vital  powers. 


*  Senibus  autem  jpodicus  est  calor  *  *  *  *  f  rigidum  est  enim  ipsorum  corpus.     Hip- 
pocr.     Aph.  14.  Sect.  2. 

f  Non  ergo  in  sola  rigiditate  causam  senum  mortis  oportet  ponere ;  nam  ex  defectu 
irritahiiitatiSj  plurimi  in  senibus  musculi  languent,  mollesque  pendent. 

ElementaPhvsiol.  torn.  VIII.  4to.  lib.  30. 


441 

The  slowness,  the  rigidity,  and  the  difficulty  of  moving,  do  not  depend 
so  much  as  is  thought,  on  the  induration  of  the  ligaments  and  other 
fibrous  organs :  these  ligaments  become  softened  and  relaxed  to  a  con- 
siderable degree,  so  that  luxation  is  more  easily  performed,  after  death, 
in  old  people.  In  them,  likewise,  organs,  which,  in  youth,  have  a  de- 
gree of  consistency,  become  flaccid  and  soft:  this  is  the  case  with  the 
heart,  which  becomes  collapsed  in  old  people,  its  cavities  remaining  en- 
tire, while  in  young  persons,  and  in  adults,  their  parietes  are  not  in  close 
contact. 

The  brain  becomes  harder  and  firmer,  less  soluble  in  alkalies;  its 
albumen  appears  more  completely  oxydized  than  in  younger  subjects  : 
impressions  are  less  easily  made,  and  the  motions  necessary  to  the  ope- 
rations of  the  understanding  are  performed  with  difficulty.  Hence,  in 
decrepitude,  man  returns,  as  far  as  relates  to  his  intellectual  faculties,  to 
a  state  of  second  childhood,  limited  to  certain  recollections,  which  are 
at  first  confused,  and,  in  the  end,  completely  lost,  incapable  of  judgment 
or  will,  or  of  new  impressions ;  sleep  resumes  its  influence  ;  reduced  to 
a  mere  vegetative  existence,  he  sleeps  the  greatest  part  of  the  day,  and 
wakens  only  to  satisfy  his  physical  wants,  and  to  take  food,  which  he 
digests  very  imperfectly;  for,  in  the  first  place,  the  want  of  teeth  pre- 
vents his  being  able  to  divide  sufficiently  the  different  substances,  and  iu 
the  next  place,  the  supply  of  saliva,  of  gastric  and  intestinal  juices,  is  al- 
most interrupted  ;  the  bile  and  other  fluids  are  less  active,  and  the  intes- 
tinal tube  is  without  energy.  Universal  rigidity  will  be  admitted  as  one 
of  the  principal  causes  of  death,  if  it  be  considered  that  women,  in  whom, 
the  organs  are  naturally  softer,  are  longer  in  reaching  that  state^  are  more 
retentive  of  life  than  men,  and  generally  live  to  a  greater  age. 

The  body,  therefore,  dies  slowly,  and  by  degrees,  says  the  eloquent 
De  Buffon ;  life  gradually  becomes  extinguished,  and  death  is  but  the 
last  term  of  this  series  of  degrees,  the  last  shade  of  life. 

CCXXXIX.  Of  Death,  Long,  in  fact,  before  the  close  of  life,  man 
loses  the  power  of  reproduction  ;  and,  in  the  course  of  the  agony  which 
serves  as  a  passage  between  life  and  death,  the  organs  of  sense  first  be- 
come insensible  to  all  sorts  of  impressions ;  the  eyes  grow  dim,  the  cor- 
nea fades,  the  eye-lids  close,  the  voice  becomes  extinct,  the  limbs  and  the 
trunk  motionless  5  yet  the  circulation  and  respiration  continue  to  be  car- 
ried on,  but  at  least  cease,  first  in  the  vessels  farthest  from  the  heart,  and 
then  gradually  in  the  vessels  nearest  that  organ.  Respiration,  gradually 
slackened,  being  entirely  suspended  after  a  strong  expiration*,  the  lungs 
no  longer  transmit  the  blood\vhich  the  veins  bring  from  every  quarter 
to  the  heart.  This  fluid  stagnates  in  the  right  cavities  of  the  heart,  and 
these  die  last,  (ultimum  moriens)  and  distended  by  the  blood  which  col- 
lects within  them,  they  attain  a  capacity  exceeding  greatly  that  of  the 
left  cavities,  which  are,  to  a  certain  degree,  emptied. 


*  Noii  ergo  in  sola  rigiditate  causam  senmin  mortis  opertet  poncre ;  nara  ex  defect'1, 
irritabilitatis,  plurimi  in  senibus  musculi  languent,  mollesque  pendent. 

Elementa  Physiol.  torn.  VIII,  4to.  lib.  30. 

f  Does  this  last  and  powerful  expiration,  often  attended  by  sighing,  depend  on  the 
spasmodic  contraction  of  the  muscles  of  expiration  ;  or  rather  does  it  not  depend  on  the 
re-action  of  the  elastic  pails  which  form  the  chest,  a  re-action  which  suddenly  cease0 
tp  be  counterbalanced  by  the  vital  properties  ?~.rfuthQr's  Note, 

3K 


442 

Such  is  the  course  of  natural  death;  the  brain  ceases  to  receive 
the  weakened  heart,  a  sufficient  quantity  of  blood  to  keep  up  sensibility; 
there  remains  still  some  degree  of  contractility  in  the  respiratory  mus- 
cles ;  it  is  soon  exhausted,  however,  and  the  circulatory  motion  of  the 
blood  ceases  with  the  life  of  all  the  organs,  of  which  this  fluid  is  one  of 
the  principal  movers. 

As  to  accidental  death,  it  is  always  determined  by  the  cessation  of  the 
action  of  the  heart  and  brain ;  for,  the  death  of  the  lungs  occasions 
that  of  the  whole  body,  only  by  preventing  the  action  of  the  heart,  by  in- 
terrupting its  influence  oil  the  encephalic  organ.  In  natural  death, 
therefore,  life  becomes  extinguished,  from  the  circumference  to  the 
centre;  in  accidental  death,  on  the  contrary,  the  centre  is  affected  be- 
fore the  extremities. 

Bichat,  in  his  work  entitled,  Eecherches  sur  la  vie  et  la  mort,  has  given  a 
very  complete  account  of  the  manner  in  which  the  organs  of  the  animal 
economy  cease  to  act  in  articulo  mortis  5  but  like  all  the  authors  who 
went  before  him,  he  has  limited  his  inquiries  to  certain  functions.  No 
one  has  attempted  to  extend  them  to  the  phenomena  of  the  action 
of  the  brain,  nor  has  one  traced  the  order  in  which  the  various 
faculties  of  thought  and  of  sensation  vanish.  I  shall  endeavour  faith- 
fully to  mention  the  results  of  several  hundred  observations  of  my  own 
on  this  subject. 

The  close  of  life  is  marked  by  phenomena  similar  to  those  with  which 
it  began.  The  circulation  first  manifested  itself,  and  ceases  last.  The 
right  auricle  is  the  part  first  seen  to  pulsate  in  the  embryo,  and  in  death 
is  the  last  to  retain  its  motion.  The  phenomena  of  nutrition,  to  which 
the  foetal  existence  is  almost  entirely  limited,  continue,  even  when  the 
organs  destined  to  establish  a  relation  with  the  beings  that  surround  us, 
have  long  been  sunk  into  a  slumber  from  which  they  are  never  to  be 
moused. 

The  following  is  the  order  in  which  the  intellectual  faculties  cease  and 
are  decomposed*.  Reason,  the  exclusive  attribute  of  man,  first  forsakes 
him.  He  begins  by  losing  the  faculty  of  associating  judgments,  and  then 
of  comparing,  of  bringing  together,  and  of  connecting,  a  number  of  ideas, 
so  as  to  judge  of  their  relations.  The  patient  is  then  said  to  have 
lost  his  conciousness,  or  to  be  delirious.  This  delirium  has  generally 
for  its  subject  the  ideas  that  are  most  familiar  to  the  patient,  and  his  pre- 
vailing passion  is  easily  recognized.  The  miser  talks,  in  the  most  in- 
4iscreBt  manner,  of  his  hidden  treasures,  the  unbeliever  dies  haunted  by 
religious  apprehensions.  Sweet  recollections  of  a  distant  native  land, 
then  it  is  that  ye  return  with  your  all  powerful  energy  and  delight ! ! 

After  reasoning  and  judgment,  the  faculty  of  associating  ideas  is  next 
completely  destroyed.  The  same  occurs  in  fainting,  as  I  once  experien- 
ced in  myself:  I  was  conversing  with  one  of  my  friends,  when  I  experi- 
enced an  insuperable  difficulty  in  associating  two  ideas,  from  the  compa- 
rison of  which  I  wished  to  form  a  judgment.  Yet  syncope  was  not  com- 
plete,! still  preserved  memory  and  the  faculty  of  feeling.  I  could  dis- 


*  I  need  not  inform  the  reader,  that  I  am  not  here  speaking1  of  the  immortal  soul, 
of  that  divine  emanation  which  outlives  matter,  and  which,  freed  from  our  perishable 
part,  returns  to  the,  Almighty.  I  am  speaking  merely  of  the  intellectual  faculties  com- 
mon to  man,  and  to  those  animals,  which,  like  him,  are  provided  with  a  brain. — Ait* 


tUictly  hear  those  about  me  say,  he  is  fainting,  and  exert  themselves  tu 
relieve  me  from  this  condition,  which  was  not  without  enjoyment. 

The  memory  then  fails.  The  patient  who,  during  the  early  part  of  his 
delirium,  recognized  the  persons  about  him,  no  longer  knows  his  nearest 
and  most  intimate  friends. 

At  last,  he  ceases  to  feel,  but  his  senses  vanish  in  succession  and  in  a 
a  determinate  order;  the  taste  and  smell  cease  to  give  any  sign  of  exist- 
ence; the  eyes  become  obscured  by  a  dark  and  gloomy  cloud ;  the  ear  is 
yet  sensible  to  sound  and  noise,  and  no  doubt  it  was,  on  this  account,  that 
the  ancients,  to  ascertain  that  death  had  really  taken  place,  were  in  the 
habit  of  calling  loudly  to  the  deceased. 

A  dying  man,  though  no  longer  capable  of  smelling,  tasting,  hearing, 
and  seeing,  still  retains  the  sense  of  touch :  he  tosses  about  in  his  bed, 
moves  his  arms  in  various  directions,  and  is  perpetually  changing  his 
posture  :  he  performs,  as  was  already  said,  motions  similar  to  those  of 
the  foetus,  within  the  mother's  womb 

CCXL.  Of  the  fieriod  of  death.  This  period  is  nearly  the  same  with 
all  men,  whether  they  live  near  the  poles,  or  under  the  equator,  whether 
they  live  exclusively  on  animal  or  vegetable  substances,  whether  they 
lead  an  active  life,  or  consume  their  existence  in  disgraceful  sloth,  few 
live  beyond  a  hundred  years.  There  are,  however,  cases  of  men  who 
have  lived  far  beyond  that  period,  as,  for  example,  those  mentioned  in 
the  Philosophical  Transactions,  one  of  whom  lived  to  a  hundred  and 
sixty-five. 

Few  men,  however,  attain  a  hundred  years,  and  death  even  when  na- 
tural, overtakes  us  from  the  age  of  seventy-five  to  a  hundred. 

Difference  of  climate,  though  producing  no  difference  in  the  duration 
of  life,  has,  however,  a  remarkable  influence  on  rapidity  of  growth.  Pu- 
berty, manhood,  and  old  age,  come  on  much  sooner  in  warm  climates 
than  in  northern  countries,  but  this  premature  developement,  which 
shortens  the  duration  of  the  periods  of  life,  augments,  in  the  same  pro- 
portion, that  of  old  age. 

It  is,  however,  difficult  to  say,  at  what  precise  period  old  age  begins. 
Is  it  towards  the  fortieth  year,  when  the  body  begins  to  decrease  and  to 
decay  ?  Can  the  change  of  the  colour  of  the  hair  be  considered  as  the 
certain  sign  of  old  age  ?  We  daily  see  young  men  with  grey  hair.  May 
we  determine  its  accession  by  the  cessation  of  the  functions  of  generation 
and  the  incapacity  of  reproduction  ?  Fecundity,  whose  term  is  so  easily 
determined  in  women,  by  the  cessation  of  the  menses,  is  in  man  very 
equivocal;  the  emission  of  the  seminal  fluid  is  an  uncertain  sign,  from 
the  difficulty  of  distinguishing  the  mucus  of  the  vesiculx  seminales  and 
of  the  prostate,  from  the  truly  prolific  semen.  Erection  is  likewise  a 
sign  not  to  be  relied  upon:  this  state  may  be  occasioned  by  sympathetic 
irritation,  by  the  compression  of  the  bladder,  distended  with  urine,  on 
the  vcsiculae  seminales.  It  is  more  difficult  than  is  imagined,  to  deter- 
mine, from  observation,  the  period  at  which,  in  the  human  species,  the 
male  is  entirely  deprived  of  the  power  of  generation  ;  and  it  may  be  said 
that,  in  establishing  the  period  of  from  forty-five  to  fifty-five,  as  the  be- 
ginning of  old  age  in  our  climate,  there  will  be  found  men  arrived  at  that 
state  before  having  reached  that  age;  as,  on  the  other  hand,  others  will 
be  found  after  the  age  of  fifty-five  with  all  the  characters  of  manhood. 
The  climaterical  period  of  sixty-three  is  the  decided  and  confirmed  pe- 


444 

riod  of  old  age.  Whatever  regimen  may  have  been  followed,  man  at 
that  age  is  truly  old,  and  cannot  but  be  aware  of  it. 

CCLXI.  Of  the  jirobabilities  of  human  life.  Man  dies  at  all  ages  5  and 
if  the  duration  of  his  life  Surpasses  that  of  the  lower  animals,  the  grcai: 
number  of  diseases  to  which  he  is  liable,  renders  itmuch  more  uncertain, 
and  is  the  cause  why  a  much  smaller  number  arrive  at  the  natural  term 
of  existence.  It  has  been  attempted  to  discover  what  are  the  probabili- 
ties of  life,  that  is,  to  ascertain,  from  observation,  how  long  a  man  may 
expect  fo  live,,  who  has  already  reached  a  determinate  age.  From  late 
accurate  observations  of  the  age  at  which  a  number  of  persons  have  .died* 
and  from  a  comparison  of  the  deaths  with  the  births,  it  has  been  ascer- 
tained) that  about  one-fourth  of  the  children  that  are  born,  die  within 
the  first  eleven  months  of  life  :  one-third  between  twenty-three  months  5 
and  one-half  before  they  reach  the  eighth  year.  Two-thirds  of  mankind 
die  before  the  thirty-ninth  year,  and  three-fourths  before  the  fifty-first;  so 
that,  as  Buffbn  observes,  of  nine  children  that  are  born,  only  one  arrives 
at  the  age  of  seventy-three ;  of  thirty,  only  one  lives  to  the  age  of  eighty; 
while  out  of  two  hundred  and  ninety-one,  one  only  lives  to  the  age  of 
ninety;  and  in  the  last  place,  out  of  eleven  thousand  nine  hundred  and 
ninety-six,  only  one  drags  on  a  languid  existence  to  the  age  of  a  hundred 
years. 

The  mean  term  of  life  is,  according  to  the  same  author,  eight  years, 
in  a  new-born  child.  As  the  child  grows  older,  his  existence  becomes 
more  secure,  and  after  the  first  year,  he  may  reasonably  be  expected  to 
live  to  the  age  of  thirty-three.  Life  becomes  gradually  firmer  up  to  the 
age  of  seven,  when  the  child,  after  going  through  the  dangers  of  denti- 
tion, will  probably  live  forty-two  years  and  three  months.  After  this  pe- 
riod, the  sum  of  probabilities,  which  had  gradually  increased,  undergoes 
a  progressive  decrease;  so  that  a  child  of  fourteen  cannot  expect  to  live 
beyond  thirty-seven  years  and  five  months ;  a  man  of  thirty,  twenty-eight 
years  more ;  and,  in  the  last  place,  a  man  of  eighty-four,  one  year  only. 
From  the  eighty-fifth  to  the  ninetieth  year,  probabilities  remain  station- 
ary, but  after  this  period,  existence  is  most  precarious,  and  is  painfully 
carried  on  to  the  end.  Such  is  the  result  of  observation,  and  of  calcula- 
tions on  the  different  degrees  of  probability  of  human  life,  by  Halley, 
Graunt,  Kersboom,  Wargentin,  Simson,  Deparcieux,  Dupre  de  St.  Maur, 
Buffon,  d'AIembert,  Barthez,  and  M.  Mourgues,  who  has  just  published 
his  observations,  collected  at  Montpelier,  in  the  course  of  a  great  number 
of  years,  and  with  the  most  scrupulous  accuracy*. 


*  From  the  observations  made  during  more  recent  periods,  it  would  appear  that  the 
mean  duration  of  human  life  has  experienced  an  increase  of  nearly  five  years  in  the 
greater  number  of  European  countries.  This  may  be  in  some  measure  owing  to  the 
introduction  of  vaccination,  but  perhaps  the  chief  causes  may  be  found  in  the  progress 
of  science  and  civilization,  giving  rise  to  a  general  improvement  in  the  habits  of  life, 
particularly  with  regard  to  ventilation  and  cleanliness  ;  to  better  habitations;  a  more 
ample  supply  of  food,  clothing,  and  fuel;  greater  sobriety;  a  more  general  cultivation 
of  the  soil,  and  consequent  removal  of  the  sources  of  several  diseases;  to  improved  ma- 
nagement of  children  ;  and  to  the  advanced  state  of  medical  knowledge. 

The  same  causes  that  conduce  to  longevity  must,  of  course,  increase  the  population  of 
a  country.  The  suppression  of  monastic  celibacy,  and  the  more  equal  distribution  of 
landed  property,  consequent  on  the  revolution  in  France,  have  tended  to  increase  the 
population  of  that  country,  notwithstanding  the  destructive  wars  in  which  she  has  been 
engaged. —  Copland 


I  should  enter  more  fully  Into  this  subject,  but  that  it  belongs  more  to 
the  department  of  political  economy  than  to  that  of  physiology. 

Do  the  calculations  on  the  probabilities  of  human  life  present  results 
applicable  to  the  generality  of  cases,  and  is  the  mean  duration  of  exist- 
ence nearly  the  same  with  all  men,  in  all  countries  and  climates  ?  The 
shepherd  of  the  Pyrenees,  who  lives  happy  in  the  innocence  of  a  pastoral 
life,  breathing  the  pure  air  of  his  mountains,  is  he,  in  this  respect,  sub- 
ject to  the  same  laws  as  the  inhabitant  of  populous  cities,  exposed  to  the 
inconveniences  attending  numerous  collections  of  men  ;  inconveniences 
which,  viewed  in  a  philosophical  point  of  view,  or  which  greatly  over- 
rated, have  so  often  furnished  a  text  to  the  meditations  of  philosophy, 
and  to  the  idle  declamations  of  oratory*. 

Does  life  experience  a  progressive  diminution,  in  proportion  to  the 
duration  of  the  world,  and  to  say  nothing  of  the  time  preceding  theflood, 
when,  according  to  the  Book  of  Genesis,  men  lived  several  hundred  years, 
-'*  ..  i  • i.  .. , . ..  .. ...  j.  i  -  -  - 

*  In  order  to  answer  these  questions  in  a  satisfactory  manner,  it  would  be  necessary 
to  have  tables  of  mortality  kept  with  care  in  the  different  countries  and  climates  of  the 
globe.  The  religions  and  superstitions  of  the  East,  of  all  Africa,  and  of  a  great  part  of 
America,  oppose  invincible  obstacles  to  these  researches,  independently  of  those  re- 
sulting from  the  state  of  civilization,  and  the  policy  of  the  various  governments  of  these 
countries.  Judging1,  however,  from  the  results  already  before  us,  the  northern  king- 
doms of  Europe  appear  to  be  those  in  which  mankind  enjoys  the  longest  term  of  exist- 
ence. The  tables  of  mortality  of  the  empire  of  Russia,  for  the  year  1811,  gave  in 
828,561  individuals  deceased  belonging  to  the  Greek  church,  947  who  had  reached  an 
hundred  years  and  upwards  ;  amongst  whom  were  83  of  115  years  of  age,  51  of  120,  21 
of  125,  7  of  130, 1  of  135,  and  another  who  had  reached  140.  m  • 

According  to  the  abstract  of  the  population  returns  of  Great  Britain  in  1821,  the  num- 
ber of  individuals  in  England,  aged  from  90  to  100  years,  was  9.90  in  every  20,000 ;  and, 
of  those  aged  100  and  upwards,  34  :  the"  general  mortality  was  1  in  67.  In  Scotland, 
those  aged  from  90  to  100  was  14.13,  and  100  and  upwards  1.03,  in  every  20,000.  In 
Wales,  the  number  of  persons  aged  from  90  to  100  was  17-97,  and  of  those  aged  100 
and  upwards,  50  in  20,000  :  the  mortality  was  1  in  69. 

The  maximum  longevity  was  found  to  be  in  Scotland  in  the  shire  of  Ross  and  Cro- 
marty.  Here  the  proportion  of  individuals  aged  from 90  to  100  was  34.39  to  the  20,000, 
and  of  those  aged  100  and  upwards  9.22.  In  the  shires  of  Inverness  and  Argyle,  the 
proportion  of  persons  aged  from  90  to  100  were  32.49  and  29.84,  respectively,  to*  20,000. 
In  1811,  the  population  of  Scotland  was  1,865,900  ;  in  1821  it  was  2,135,300. 

The  first  actual  enumeration  of  the  inhabitants  of  England  and  Wales  was  made  in 
1801,  and  gave  a  population  of  9,168,000,  and  a  mortality  of  1  in  44.8.  The  second  was 
made  in  1811,  and  gave  a  population  of  10,502.900,  and  a  mortality  of  1  in  50.  The  third 
and  last,  which  took  place  in  1821,  has  given  an  enumeration  of  12,218,500,  and  a  mor- 
tality of  1  in  58. 

It  appears  from  these  returns,  that  the  healthiest  counties  in  England  and  Wales  are 
Pembroke,  Sussex,  Cornwall,  Cardigan,  and  Monmouth,  the  mortality  in  these  being  1 
in  about  71  ;  and  that  the  least  salubrious  are  Middlesex,  Kent,  Surry,  and  Warwick,  the 
mortality  being  in  these  1  in  about  50.  It  is  not  easy  to  explain  altogether  the  differ- 
ence  in  salubrity  in  the  different  countries.  Locality  is,  doubtless,  an  important  agent. 
Cities  and  large  manufacturing  towns  modify  greatly  the  ratio  of  mortality  in  a  particu- 
lar district.  This  is  well  illustrated  with  respect  to  "London.  In  1700,  the  annual  mor- 
tality of  this  city  was  1  in  25 ;  in  1750,  1  in  21 ;  in  1801,  and  the  four  preceding  years,  1 
in  35 ;  in  1810, 1  in  38  ;  and  in  1821,  1  in  40. 

It  must  be  evident  that  the  increase  or  diminution  of  the  population  of  a  district,  as 
well  as  the  mean  term  of  life  in  it,  must  depend  upon  the  nature  of  the  climate  and  soil, 
its  mean  elevation  and  temperature,  the  state  of  its  civilization  and  cultivation,  pursuits 
of  its  inhabitants,  and  means  of  subsistence.  The  government  and  religion  of  a  country 
also  exert  no  inconsiderable  controul  on  the  mean  duration  of  human  life,  and  increase 
of  its  population.  Together  with  these  already  mentioned,  many  other  causes  of  a 
moral  and  physical  nature  may  be  adduced,  as  influencing,  in  no  slight  degree,  the  ex- 
tent, of  population,  and  the  salubrity  of  a  district  or  country. — Copland* 


446 

did  the  men  of  former  times  live  longer  than  those  of  our  own?  This  is 
very  improbable  :  among  the  Egyptians,  the  Hebrews,  the  Greeks,  and 
Romans,  there  were  very  few  instances  of  persons  living  to  the  age  of  a 
hundred  years,  and  instances  of  longevity  are  perhaps  more  frequent 
among  the  moderns. 

The  art  of  providing  for  the  wants  of  life,  making  daily  progress,  it  is 
very  probable,  that  far  from  being  shortened,  the  term  of  human  life  may 
be  lengthened  a  certain  number  of  years  beyond  its  ordinary  duration. 
This  idea  is,  it-is  true,  contrary  to  the  commonly  received  opinion  of  the 
progressive  depravity  of  mankind  in  all  ages  ;  but  the  golden  age  never 
existed  but  in  the  imagination  of  poets.,  and  the  daily  complaints  of  mo- 
rose old  age  have  their  origin  in  motives  easily  understood  by  the  phy- 
siologist. He  whose  sentiment  is  blunted  by  a  long  course  of  years,  is 
affected,  in  a  very  different  manner,  by  surrounding  objects.  As  to  the 
old  man,  flowers  have  lost  their  scent  and  beauty,  fruits  no  longer  retain 
their  flavour.  The  whole  of  nature  seems  dull  and  colourless.  But  the 
cause  of  all  these  changes  is  within  himself,  every  thing  else  remains  as 
it  was.  Always  equally  fruitful,  Nature  exposes  every  thing  to  the  action 
of  her  inexhaustible  crucible  ;  maintains  every  thing  in  a  state  of  ever- 
lasting youth,  and  preserves  a  freshness  ever  renewed.  Individuals  die, 
opecies  are  renovated  :  life  every  where  arises  in  the  midst  of  death.  The 
materials  of  organized  bodies  enter  into  new  combinations,  and  serve  in 
forming  new  beings,  when  life  ceasing  to  animate  those  to  which  they  be- 
longed, putrefaction  seizes  upon  them,  and  effects  their  destruction. 

CCXLII.  Of  putrefaction.  Here  the  history  of  life  ought  to  termi- 
nate; if,  however,  it  be  considered  that  the  changes  which  bodies  expe- 
rience, after  death,  throw  a  considerable  light  on  its  means,  its  ends, 
and  its  nature,  there  will  be  an  obvious  necessity  for  shortly  inquiring 
Into  the  different  phenomena  which  accompany  the  decomposition  of 
animal  substances.  And  this  investigation  appears  to  me  to  belong  to 
the  department  of  physiology,  until  the  aspect  of  the  body  ceases  to  re- 
call the  idea  of  its  former  state,  and  until  the  last  lineaments  of  organi- 
zation are  completely  effaced.  As  soon  as  life  forsakes  our  organs,  they 
become  subject  to  the  laws  of  physics.,  operating  upon  substances  that  are 
not  organized.  An  inward  motion  takes  place  within  their  substance. 
and  their  molecules  have  the  greater  tendency  to  become  separated  from 
one  another,  as  their  composition  is  more  advanced.  Chemistry  informs 
us  that  the  tendency  to  decomposition  of  bodies  is  in  direct  ratio  to  the 
number  of  their  elements,  and  that  a  dead  animal  body  is  capable  of  re- 
maining unchanged,  in  proportion  as  its  composition  is  more  simple,  and 
its  constituent  principles  less  numerous  and  less  volatile. 

Before  putrefaction  can  come  on  in  the  human  body,  it  must  be  en- 
tirely deprived  of  life,  for  the  vital  powers  are  most  powerfully  antisep- 
tic, and  one  might  say  that  life  is  a  continued  struggle  against  the  laws 
of  physics  and  chemistry.  This  vital  resistance,  alluded  to  by  the  ancients 
when  they  said,  that  the  laws  of  microcosm  were  in  perpetual  opposition 
to  those  of  the  universal  world,  and  that  these,  in  the  end,  prevailed;  this 
power,  which  is  in  a  state  of  perpetual  re-action,  manifests  itself  in  life  : 
the  latter,  considering  only  the  results,  might,  therefore,  be  defined  as 
follows :  the  resistance  ofiposed  by  organic  bodies  to  the  causes  incessantly 
tending  to  their  destruction.  By  attending  to  all  these  phenomena,  it  will 
be  seen  that  all  of  them  tend  to  one  end,  the  preservation  of  the  body, 
and  that  they  obtain  it,  by  keeping  up  a  perpetual  struggle  with  the  laws 
which  govern  inorganic  substances. 


447 

Tf  might  appear  singular,  that  death  should  aftorcl  a  just  idea  of  life, 
did  we  not  know  that  it  is  by  comparing,  that  we  are  enabled  to  distin- 
guish, to  judge,  and  to  arrive  at  knowledge*. 

Putrefaction  takes  place  and  is  completed,  only  in  substances  deprived 
of  life.  A  mortified  limb  loses  its  vitality,  before  putrefaction  comes  on; 
and  if  nature  preserve  sufficient  energy  to  resist  this  destructive  process, 
she  draws,  by  a  line  of  inflammation,  the  separation  between  the  dead 
and  the  living  part.  Life  and  putrefaction  are,  therefore,  two  absolutely 
contradictory  ideas  ;  and  when,  in  some  diseases,  there  is  observed  a  ten- 
dency in  solids  and  fluids  to  spontaneous  decomposition,  this  tendency  to 
putrefaction  should  not  be  mistaken  for  putrefaction  itself. 

Several  conditions  are  required  to  enable  putrefaction  to  affect  the  hu- 
man body  after  death.  In  the  first  place,  a  mild  temperature,  that  is, 
above  ten  degrees  of  Reaumur's  thermometer ;  in  the  next  place,  a  cer- 
tain degree  of  moisture;  and  lastly,  the  presence  of  air.  This  last  con- 
dition, however,  is  not  so  necessary  as  the  two  former,  since  substances 
undergo  putrefaction  in  a  vacuum,  though  more  slowly.  The  air  conse- 
quently promotes  a  decomposition,  only  by  carrying  off  the  element  which 
rises  in  vapours.  On  the  other  hand,  an  icy  cold,  or  a  degree  of  heat  ap- 
proaching to  boiling,  prevents  it;  the  former,  by  condensing  the  parts  ; 
the  second,  by  ""depriving  them  of  moisture,  the  complete  absence  of 
which,  accounts  for  the  preservation  of  the  Egyptian  mummies. 

The  phenomena  of  putrefaction,  resulting  from  a  series  of  peculiar  at- 
tractions, are  modified  in  various  ways,  according  to  the  nature  of  the 
animal  substances  which  are  subjected  to  it,  to  the  media  in  which  it 
takes  place,  to  the  different  degrees  of  moisture  and  temperature,  and 
even  according  to  its  different  periods.  Notwithstanding  these  innume- 
rable varieties,  one  may  say,  that  all  exhale  a  certain  cadaverous  smell, 
are  softened,  increase  in  bulk,  acquire  heat,  change  colour,  assume  .a 
greenish,  then  a  livid  and  dark  brown  colour  5  there  are,  at  the  same 
time,  disengaged  a  great  number  of  gaseous  substances,  of  which  ammo- 
nia is  the  most  remarkable,  either  from  its  quantity,  or  from  being  given 
out  by  animal  substances,  from  the  moment  when  decomposition  begins, 
to  the  period  of  the  most  complete  dissolution.  This  gas  produces  the 
pungent  and  putrid  smell  which  exhales  from  dead  bodies. 

Towards  the  termination  of  putrefaction,  there  is  disengaged  carbonic 
acid  gas,  which,  combining  with  ammonia,  forms  a  fixed  and  crystalliza- 
ble  salt.  Besides  these  products,  there  are  given  out  sulphuretted  and 
phosphoreited  hydrogen,  or  combined  with  azote,  carbonic  acid,  and  all 
the  substances  which  may  be  produced  by  their  respective  combinations. 
In  the  last  place,  animal  substances,  when  reduced  to  a  residue  containing 
oils  and  salts  of  different  kinds,  form  a  mould,  from  which  plants  draw 
the  principles  of  a  luxuriant  and  vigorous  vegetation.  The  bones,  those 
least  alterable  parts  of  the  organized  machine,  in  time,  become  dried  by 
the  slow  combustion  of  their  fibrous  part,  and  by  the  evaporation  of  their 
medullary  juices.  At  last,  reduced  to  an  earthly  skeleton,  they  crumble 
into  dust,  and  this  dnst  is  dissipated,  on  opening  the  tombs  in  which  they 
were  laid. 

Thus,  in  the  course  of  time,  is  effaced  all  that  could  recall  the  idea  of 
our  physical  existence. 


*  See  APPENDIX,  Note  M  M^  for  some  remarks  on  the  signs  of  deatk 


448 

Putrefaction,  considered  in  a  philosophical  point  of  view,  is  but  a 
means  employed  by  nature,  to  restore  our  organs,  deprived  of  life,  to  a 
more  simple  composition,  in  order  that  their  elements  may  be  applied  to 
new  creations  (circulus  xterni  motus*.  Nothing,  therefore,  is  better  proved, 
than  the  metempsychosis  of  matterf  ;  which  warrants  the  belief  that  this 
religious  dogma,  like  most  of  the  fabulous  worships  and  imaginations  of 
antiquity,  is  but  a  veil  ingeniously  thrown  by  philosophy,  between  nature 
and  the  ignorant. 


*  Beecher,  physica  subterranea. 

f  Matter  is  eternal,  in  this  sense,  that  the  molecules  of  bodies  merely  pass  from  the 
one  into  the  other;  they  survive  the  destruction,  or  rather  the  dissolution  of  organic 
and  inorganic  beings,  when  the  former,  ceasing  to  live,  restore  to  the  inexhaustible 
fund  of  Nature,  those  elements  which  she  lends  without  ever  parting  with  them. 

Manciple  nulli  datur,  omnibus  usu.    Lucret  lib.  III. — Author's  Note, 


APPENDIX 


BY  JAMES  COPLAND,  M.  I). 


CHAPTER.    I. 

Of  Life. 
Note  A. 

PtfYSioiOGiSTS  are  divided  into  those  admitting  a  principle  of  life,  and  those  attribu- 
ting the  vital  phenomena  to  organization  solely — the  latter  class  contending  that  life 
pre-supposes  organization,  the  former  that  organization  pre -supposes  the  presence  of 
life.  An  attentive  consideration  of  the  phenomena  presented  by  the  whole  range  of  or- 
ganized bodies,  and  a  fair  contrast  instituted  between  these  and  the  changes  which  inani- 
mate matter  exhibits,  will  readily  convince  the  most  unbiassed  by  preconceived  notions, 
which  of  the  two  doctrines  to  prefer. 

Those  who  contend  that  life  is  the  result  of  organization,  ought  to  explain  in  what 
manner  the  organization  itself  took  place  ;  they  should  show  the  means  employed  to 
produce  the  disposition  of  parts,  which  they  conceive  requisite  to  give  rise  to  vital 
phenomena.  If  they  deny  the  primary  influence  of  a  vital  power,  associated  with  the 
particles  of  matter,  let  them  explain  by  what  other  agency  the  different  atoms  can  as- 
sume organic  actions.  All  effects  must  have  a  cause,  and  it  is  better  to  assign 
one  according  to  which  difficulties  may  be  accounted  for,  than  to  contend  for  the  effi- 
ciency of  properties  or  powers,  of  the  existence  of  which  we  have  no  evidence,  and 
which,  even  granting  them  to  exist,  can  only  be  considered  as  inferior  agents,  or  cer- 
tain manifestations  of  a  vital  principle. 

With  respect  to  this  class  of  Physiologists,  it  may  be  remarked  generally  ; — 1st.  That 
explanations  of  organization,  which  admit  not  of  the  primary  and  controlling  influ- 
ence of  vitality,  however  applicable  they  may  seem  to  those  who  look  only  at  the  gross 
relations  of  things,  cannot  satisfactorily  account  for  the  origin  and  nature  of  the  pheno- 
mena to  which  they  relate  ;  for,  however  terms  may  be  substituted,  or  illustrations  mul- 
tiplied, the  changes  which  continually  take  place  in  living  bodies  cannot  be  explained 
by  means  of  the  laws  and  affinities  which  characterize  the  combinations  of  inorganized 
matter. 

2d,  In  order  to  explain  the  phenomena,  which  are  more  justly  ascribed  to  a  vital 
principle,  the  supporters  of  the  doctrine  of  organism  have  recourse  to  the  substitution 
of  properties,  occult-qualties,  impulses,  and  motions ;  and  when  required  to  show 
wherein  these  qualities,  impulses  and  properties  are  different  from  those  which  we  ob- 
serve in  inorganized  matter,  and  are  there  subjected  to  our  experience,  they  endea- 
vour to  get  rid  of  the  difficulty  by  denominating  them  vital,  thus  tacitly  admitting  the 
very  principle,  in  the  place  of  which  such  insufficient  properties  are  attempted  to  be 
substituted ;  and  after  all,  without  the  smallest  success  in  preventing  a  recurrence  to 
this  principle,  of  which  all  these  properties,  admitting  their  existence,  are  nothing 
else  than  the  results :  for,  however  we  may  denominate  them,  we  merelv  substitute  ex- 
pressions which  (if  they  convey  any  meaning)  imply  only  the  existence  of  certain  effects 
or  operations,  which  are  inferior  agents  or  instruments,  under  the  controul  of  vitality  h: 
the  production  of  the  organic  phenomena. 

From  this  view,  therefore,  of  the  subject,  it  appears  that  the  argument  used  against 
the  existence  of  a  vital  principle  is  more  verbal  than  real.  The  organists  cannot  even 
prove  the  basis  of  their  doctrine,  for  they  cannot  show  that  organization  came  into  ex- 
istence before  the  effects  which  they  impute  to  it ;  and  while  they  bestow  propertied  and 

A. 


2  APPENDIX. 

qualities  on  organized  matter-similar  to  those  imputed  to  a  vital  principle,  and  different 
from  those  which  characterize  Unorganized  matter,  although  they  cannot  point  out  the 
difference  otherwise  than  by  calling  them  vital,  they  virtually  admit  the  existence  of  the 
principle  against  which  they  contend ;  for  what  principle  in  nature,  we  would  ask,  can 
be  shown  to  exist,  or  how  can  its  existence  be  rationally  inferred,  but  by  certain  pro- 
perties and  qualities,  which  are  peculiar  to  itself,  and  which,  moreover,  as  respects  this 
principle,  are  dissimilar  and  greatly  superior  to,  and  indeed  hold  a  controlling  influ- 
ence over  all  the  other  properties  of  matter  with  which  we  are  acquainted  ? 

Such  therefore  being  the  case,  we  are  justified  in  recurring  to  the  belief  in  a  vital 
principle  which,  allied  to  matter,  controls  its  changes  and  forms,  and  to  which  princi- 
ple the  laws  and  affinities  of  matter  entirely  subject  whenever  they  are  embraced  within 
its  sphere  of  action.  By  means  of  this  superior  principle,  we  are  enabled  to  explain 
the  phenomena  of  the  organized  preation  and  of  the  human  economy,  but  without  re- 
ference to  it  we  are  lost  in  the  mazes  of  vague  hypothesis  and  groundless  supposition. 

It  has  been  objected  to  the  existence  of  this  principle,  that  we  cannot  demonstrate  it 
to  the  senses  in  any  form  unconnected  with  matter.  But  we  are  not  contending  for  the 
existence  of  a  principle  which  is  material,  according  to  the  received  notions  respecting 
matter,  otherwise  there  would  be  at  once  an  end  of  the  argument ;  it  is,  therefore,  no 
evidence  of  the  non-existence  of  this  principle,  that  it  does  not  become  visible  to  our 
senses,  in  an  uncombined  form  :  it  is,  however,  sufficiently  demonstrable  by  its  effects, 
in  alliance  with  matter,  in  which  state  it  presents  proofs  of  its  being  equal  to  those  from 
which  we  infer  the  existence  of  matter  itself. 

From  these  and  many  other  considerations  that  may  be  adduced,  we  conclude  that 
life  is  a  first  principle  in  nature  ;  that  it  exists  in  various  degrees  of  energy,  and  in  di- 
versified conditions  and  forms  throughout  her  domains ;  and  that  these  diversified  states 
of  vital  existence  are  continued,  as  far  as  the  operation  of  extraneous  causes  will  admit, 
by  a  specific  process,  which  gives  rise  to  the  production  of  similar  beings  by  means  of 
ova  and  germs. 

It  will  be  perceived  that  the  generation  by  which  vegetable  and  animal  bodies  are 
perpetuated,  involve  the  belief  that  the  ova  or  germs  convey  an  emanation  from  the  pa- 
rent of  a  specific  portion  of  vitality. 

As,  however,  we  can  form  no  just  conceptions  of  such  a  principle  but  by  its  effects, 
and  as  we  have  no  experience  of  these  effects  unconnected  with  matter,  so  we  are  war- 
ranted in  the  conclusion,  that  the  vital  influence  is  associated  with  the  molecules  of 
matter  forming  the  impregnating  secretions,  and  the  sensible  bulk  of  the  ovum.  This 
is  its  lowest  state  of  activity  or  energy,  and  its  influence  is  chiefly  manifested,  under 
such  circumstances,  in  preserving  the  elements  of  matter  with  which  it  is  associated 
from  entering  into  the  combinations  to  which  the  chemical  affinities  of  these  elements 
dispose  them. 

The  hibernation  of  animals  presents  this  principle  also  in  its  lower  degree  of  activity. 
In  either  case,  and  indeed  under  every  circumstance,  it  is  a.cted  upon  and  excited  to  an 
exalted  state  of  existence  by  most  of  the  active  agents  in  nature.  The  electric  fluid, 
heat,  and  other  powers  have  this  effect,  while  some  appear  to  produce  a  contrary  im- 
pression. 

The  manner  in  which  several  of  the  active  agents  of  inorganic  nature  thus  influence 
the  energy  of  the  vital  principle  appears,  to  have  been  the  chief  reason  why  these 
powers  hare  been  substituted  for  vitality  itself. 

We  have  stated,  that  the  manifestations  of  this  principle  throughout  the  vegetable 
and  animal  kingdoms  present  considerable  difference  in  degree.  Its  character  in  the 
vegetable  creation  is  more  uniform,  and  its  phenomena  more  simple.  We  perceive  in 
this  kingdom,  under  circumstances  which  furnish  the  usual  stimuli,  that  the  vital  ope- 
rations of  digestion,  circulation,  respiration,  and  assimilation,  go  forward.  As  soon, 
however,  as  the  exciting  causes  are  withdrawn,  this  principle  subsides  to  a  state  of  less 
activity  ;  and  the  integrity  of  such  organs  and  textures  as  are  necessary  to  the  growth 
and  propagation  of  the  species,  is  merely  preserved  by  its  influence  until  a  returning 
impulse  excites  its  energies. 

As  we  advance  in  the  scale  of  the  animal  creation,  the  operations  of  this  principle  be- 
come more  distinct  and  numerous,  and  the  mechanism  provided  for  the  performance 
of  them  more  manifest  and  complex.  As  they  are  performed  in  man  and  in  the  more 
perfect  animals,  may  be  gathered  from  the  body  of  the  work  and  the  notes  which 
follow. 


OF  THE  ELEMENTARY  SOLIDS.  3 

Of  the  Nervous  System  in  the  Lower  Animals. 
Note  B. 

The  lowest  order  of  animals,  as  the  Polypi,  &c.  has  usually  been"  considered  to  be 
destitute  of  a  nervous  system.  This,  however,  is  not  the  case.  If  we  look  narrowly 
into  the  structure  of  the  lower  animals,  we  shall  find  that  even  the  lowest  offer  traces  of 
a  nervous  system  :  and  as  we  rise  through  the  scale  of  the  animal  creation,  we  shall  find 
this  system  becoming  more  and  more  perfect  in  its  state  of  existence,  and  presenting  ap- 
pearances of  perfection  in  proportion  to  the  number  and  extent  of  functions  which  the 
animal  is  capable  of  exerting.  Even  the  Polypus,  the  lowest  of  the  animal  kingdom, 
seems  to  possess  a  nervous  system,  in  the  simplest  state  of  existence.  If  this  apparently 
homogeneous  animal  be  examined  with  a  powerful  microscope,  numerous  globules,  en- 
tirely resembling  those  seen  in  the  nervous  system,  appear  disseminated  throughout  its 
structure.  As  a  result  of  this  simplicity  of  conformation,  it  presents  no  perfect  manifes- 
tation of  sensibility  and  contractility.  It  is  not  constituted  ot  separate  textures  and 
organs  destined  to  perform  specific  purposes ;  and,  consequently,  as  no  relation  or  band 
of  union  is  requisite  between  its  parts,  as  in  those  animals  which  have  particular  organs 
or  structures  which  perform,  particular  offices  ;  and  as  each  of  its  individual  parts  per- 
forms the  functions  of  the  whole  animal,  so  its  nervous  system  is  disseminated  through- 
out its  structure,  without  being  arranged  into  cords  of  communication  or  centres  of  re- 
inforcement as  in  those  animals,  which,  endowed  with  distinct  organs  and  perfect  func- 
tions, possess  both. 

As  we  rise  in  the  scale,  on  the  contrary,  we  perceive,in  the  more  perfect  and  in  the 
highest  animals,  the  intimate  texture  of  the  nervous  system,  arranged  so  as  to  form  com- 
municating chords  between  organs  which  are  distantly  separated  from  each  other,  and 
not  only  are  they  provided  with  these,  but  each  viscus  frequently  possesses  in  addition 
a  separate  nervo'us  centre,  on  which  the  functions  performed  by  that  viscus  depend  : 
whilst  the  former  arrangement  is  calculated  to  preserve  a  reciprocity  of  action — a  mu- 
tual dependence  of  parts  and  of  functions,  the  latter  generates  a  vital  influence,  modi- 
fied in  kind  and  in  degree  to  the  part  which  it  actuates,  which  influence,  in  conjunction 
with  what  the  organ  may  receive'from  a  common  centre,  and  what  may  be  generated  in 
the  nerves  of  its  own  structure,- is  exerted  in  the  production  or  the  functions  of  which 
the  conformation  of  the  organ  is  but  the  mechanical  instrument.  Thus  the  vital  in- 
fluence is  furnished  to  the  different  viscera  in  proportion  to,  and  suitably  with  the  na- 
ture of,  its  expenditure  in  the  more  complex  and  more  complete  exertion  of  the  opera- 
tions which  each  of  them  is  destined  to  fulfil. 

Respecting  this  subject,  therefore,  the  following  propositions  may  be  stated  : — That 
corpuscles  or  globules,  entirely  similar  to  those  of  which  the  nervous  system  is  com- 
posed, according  to  the  observations  of  Prochaska,  the  Wenzels,  Bauer,  and  Edwards, 
are  found  desseminated,  without  any  regular  order,  throughout  the  apparently  homo- 
geneous structure  of  the  lowest  order  of  the  animal  kingdom :  that,  as  we  rise  in  our 
observations  through  the  scale  of  animals,  we  perceive  this  dissemination  existing  only 
in  the  mucous  structures,  and  we  observe  a  distinct  nervous  mass,  or  masses;  am:,  as 
the  animal  presents  separate  organs  destined- to  the  vital  operationSj  so  this  intimate 
nervous  structure  becomes  disposed  into  cords  of  communication,  each  organ  possess- 
ing in  addition — the  higher  that  we  ascend  in  the  scale  more  especially — a  detached 
but  dependent  mass  of  reinforcement,  which  varies  in  form,  appearance,  and  connexion 
with  -other  organs,  or  with  other  parts  of  the  same  system,  according  to  the  functions 
which  it  is  destined  to  actuate. 


Of  the  Primary  Solids  and  Compound  Textures  of  the  Body. 
Note  C. 

The  intimate  or  elementary  constitution  of  the  animal  textures  has  long  engaged  the 
attention  of  Anatomists  and  Physiologists.  As  researches  respecting  this  subject  can 
only  be  prosecuted  by  means  of  the  microscope,  the  result  must,  therefore,  be  received 
with  some  degree  of  reservation,  unless  they  coincide  with  the  observations  of  former 
inquiries,  or  be  confirmed  by  subsequent  observers,  From  amongst  those  who  have 


4  APPENDIX. 

engaged  in  this  species  of  investigation,  J.  F.  Meckcl  is  entitled  to  much  confidence  on 
account  of  his  talents  and  industry,  and  the  results  of  his  labours  claim  particular  no- 
tice, as  they  confirm  much  that  has  "been  recorded  by  former  observers. 

According  to  the  views  of  this  physiologist,  the  solids  and  fluids  of  the  human  body 
may  be  reduced  to  two  elementary  substances :  the  one  is  formed  of  globules,  the  other 
of  a  coagulable  matter,  which,  either  alone  or  united  to  the  former,  constitutes  the  liv- 
ing fluids,  when  it  is  in  the  liquid  state,  and  gives  rise  to  the  solid  tissues  when  it  as- 
sumes the  concrete  form. 

The  globules  present,  in  their  nature  and  aspect,  differences  which  are  relative  to 
the  situations  in  which  they  are  examined.  They  appear  in  the  blood,  flattened,  and 
composed  of  a  central  part  which  is  solid,  and  of  an  exterior  portion,  which  is  hollow 
and  vesicular.  Those  found  in  the  kidneys  are  smaller  than  those  of  the  spleen  ;  and 
the  globules  of  the  liver  are  still  smaller.  Those  contained  in  the  substance  of  the 
nerves  present  a  less  volumn  than  those  observed  in  the  blood. 

Globules  exist  not,  according  to  Meckel,  in  the  proper  structure  of  cellular  tissue,  of 
fibrous  and  cartilaginous  parts,  and  of  the  bones.  On  the  contrary,  they  abound  in 
nerves  and  muscles,  and  determine  their  nature  and  colour.  Some  of  the  fluids,  also, 
as  the  urine,  contain  no  globules,  whilst  they  are  abundant  in  the  blood,  in  the  ch}le, 
the  lymph,  milk,  &c. 

During  the  hrst  period  of  conception,  the  mucous  and  homogeneous  mass  which  con- 
stitutes the  embryo,  contains  no  globules ;  it  is  not  until  a  more  advanced  period  that 
it  is  composed  of  two  substances,  the  one  fluid,  the  other  solid.  These  two  elements 
seem  to  influence  the  form  of  the  fibres  and  plates  in  which  animal  substances  are  dis- 
posed. The  laminated  tissues  arise  almost  exclusively  from  the  fluid  matter.  The 
fibrous  tissues  may  also  be  produced  from  this  matter  alone,  as  in  the  tendons,  &c.  ; 
they  are,  however,  more  frequently  formed  from  the  union  of  the  globules  with  the 
concretive  fluid,  as  may  be  observed  in  the  nervous  and  muscular  textures. 

These  observations  of  Meckel  respecting  animal  organization,  it  ought  to  be  noticed, 
bear  a  near  resemblance  to  the  opinion  entertained  by  Pfaff,  who  considered  the  ele- 
mentary tissues  to  be  formed  from  a  series  of  molecules  and  globules,  and  to  be  diffe- 
rent according  to  the  presence  and  influence  of  the  latter  form  of  matter.  The  idea 
of  a  fluid  substance,  capable  of  concretion,  is  analogous  to  the  opinion  of  the  ancients 
especting  the  substance  denominated  by  them  gluten.  It  is  the  cellular  tissue,  accord, 
ing  to  Meckel,  which  represents  that  substance ;  and,  in  fact,  he  regards  this  tissue  as 
a  species  of  concrete  fluid,  possessed  of  the  properties  already  indicated. 

It  must,  in  our  opinion,  be  admitted  that  the  theory  of  Meckel  possesses  claims  to  a 
favourable  notice.  It  is  the  result  of  observations  which  accord  with  those  of  others ; 
it  is  also  simple,  and  is  easily  to  be  reconciled  with  the  phenomena  which  living  tex- 
tures present. 

Dr.  Meyer,  of  Bonn,  (Journ.  Complem.  dee  Scien.  J\Tcd.  Nov.  1821.)  also  considers 
that  two  kinds  only  of  elementary  texture  exist  in  animal  bodies.  The  one  is,  accord- 
ing to  him,  composed  chiefly  of  capillary  vessels,  and  is  formed  from  the  assemblage  of 
these  vessels :  under  it  he  arranges  cellular,  serous,  fibrous,  and  mucous  tissues :  tho 
other  possesses  a  proper  and  peculiar  parenchyma,  composed  of  globules,  or  of  an  or- 
ganic pulp ;  such  are  the  glands,  the  bones,  muscles,  nerves,  the  brain,  and  spinal 
cord.  The  first  set  of  organs  is  a  continuation,  in  his  opinion,  of  the  vascular  system ; 
while  the  second,  on  the  contrary,  is  farther  removed  from  such  a  connexion.  Foreign 
substances  introduced  into  the  circulation,  pass  immediately,  and  with  rapidity,  into  the 
former  textures,  while  they  either  fail  altogether  in  penetrating,  or  insinuate  themselves 
much  more  slowly,  and  after  quite  a  different  manner,  into  the  parenchyma  of  the  lat- 
ter organs.  The  one  class  seems  to  appertain  in  general  to  the  system  of  secretion ;  the 
other  class  of  textures  neither  secrete  from  their  individual  influence,  nor  can  they  of 
themselves  add  to  their  nutrition.  The  first  appears  to  be  nourished  by  the  imme- 
diate, rapid,  and  continual  access  into  the  fluid  part  of  the  blood ;  the  second  by  a  slow 
and  periodic  deposition,  and  conversion  into  their  proper  substance,  of  the  sanguine- 
ous globules  of  the  blood,  by  means  of  the  influence  of  the  vascular  extremities  upon 
the  blood  which  they  contain. 

The  primary  solids,  or  rather,  the  elementary  fibres*  of  the  human  body,  and  of  the 


*  It  should  be  kept  in  recollection  that  fibre  is  used  as  signifying  an  elementary  ani- 
mal  substance ; — tissue  indicates  a  certain  arrangement  of  the  former— a  peculiar  struc- 
ture of  parts  : — and  organ  signifies  a  compound  or  complex  part  which  performs  func- 
tions peculiar  to  itself. 


OF  THE  ELEMENTARY  SOLIDS.  5 

higher  classes  of  animals,  cannot  be  considered  with  propriety,  to  be  more  than  three 
•—the  celhtlar  or  laminar,  the  muscular,  and  the  nervous. 

1st.  The  cellular  fibre  is  the  most  essential  to  animal  existence,  and  is  found  in  every 
individual  of  this  kingdom.  It  consists  of  an  assemblage  of  minute  lamina  and  delicate 
filaments.  It  is  neither  sensible  nor  irritable,  and  is  chiefly  composed  of  a  nearly  com- 
plete gelatine. 

2d.  The  muscular  fibre  is  not  so  generally  distributed  throughout  the  animal  kingdom 
as  the  former,  for  it  is  not  found  in  the  Zoophites. 

3d.  The  nervous  or  medullary  fibre.  The  nature  of  this  tissue  has  been  the  subject 
of  much  investigation.  Mr.  de  Blainville  thinks  that  it  originates  in  the  muscular  fibre, 
as  this  latter  takes  its  origin  in  the  cellular  substance. 

To  these  fibres  Professor  Chaussier  has  added  a  fourth,  namely,  the  albugineous  fibre, 
which  is  satiny,  white,  and  very  strong  ;  and  is  neither  sensible  nor  irritable.  The  ma- 
jority of  anatomists,  however,  consider  it  as  merely  a  very  condensed  variety  of  the 
cellular  fibre. 

These  fibres  may  be  called  the  first  order  of  solids,  as  they  serve  to  form  all  the  other 
tissues  and  organs  of  the  body.  The  cellular  substance,  for  instance,  is  spread  out, 
and  condensed  into  membranes,  or  rolled  up  in  the  form  of  vessels ;  muscular  fibres 
also  assume  the  form  of  membranes,  concur  to  the  formation  of  vessels,  and  constitute 
muscles;  nervous  fibres  produce  the  nerves,  &c.  Finally,  those  primary  solids  asso- 
ciate in  various  forms,  and  give  rise  to  the  compound  solids,  as  the  bones,  the  glands, 
&c. :  and  even  to  those  of  a  more  complex  nature,  as  several  of  the  thoracic  and  ab- 
dominal viscera.  Indeed,  every  species  of  solid  has  for  its  base  cellular  substance, 
which  is  penetrated  by  nerves  and  vessels.  The  viscera,  for  example,  are  of  this  na- 
ture, having  moreover  membranous  envelopes.  The  bones  also  consist  of  a  similar  tex- 
ture, and  of  a  deposition  of  phosphate  of  lime  in  their  cellular  substance.  (See  Ade- 
lon's  Physiol.  vol.  i.  p.  108.) 

Those  primary  solids,  or  most  simple  anatomical  constituents  which  we  have  just  now 
particularized,  associate  in  various  forms,  giving  rise  to  compound  solids  or  tissues,  which 
are  characterized  not  only  by  their  form  and  nature,  but  also  by  the  functions  which 
they  perform. 

These  animal  textures  or  compound  solids  were  first  arranged  with  any  degree  of  ac- 
curacy by  Bichat ;  and  however  successful  future  researches  into  their  ultimate  nature 
may  be,  or  whatever  classifications  may  be  proposed  by  future  inquirers,  he  is  still  en- 
titled to  the  honour  of  having  introduced  a  philosophical  analysis  into  anatomical  and 
physiological  science.  The  arrangement  of  the  tissues  which  this  great  man  adopted, 
is  as  follows : — the  exhalent,  absorbent,  cellular,  arterial,  venous,  nervous  of  animal  life, 
nervous  of  organic  life,  osseous,  medullary,  cqrtilaginoiis,  fibro-cartilaginous. fibrous,  mus- 
cular of  animal  life,  muscular  of  organic  life,  mucous,  serous,  synovial,  glandular,  dermoid, 
epidermoid  and  cor neus  or  pilous,  systems.  Mr.  Adelon  has  lately  proposed  another  classifi- 
cation, possessing  some  advantages  over  that  of  Bichat.  He  has  reduced  the  number  of 
textures  or  systems  to  twelve,  viz. — the  cellular,  vascular,  nervous,  osseous,  cartilaginous, 
fibrous,  muscular,  erectile,  mucous,  serous,  corneus  or  epidermoid,  and  parenchymatoiis. 

Professor  Mayer  has  recently  adopted  a  classification  of  the  animal  textures,  or  com- 
pound solids,  founded  on  his  views  respecting  the  elementary  fibres,  or  primary  solids. 
He  recog*nises  only  seven  systems,  viz. — 1st,  the  lamellated  tissue  ;  2d,  the  cellule-fibrous 
tissue;  3d,  the  fibrous  system ,-  4>tfi,  the  cartilaginous  tissue  :  5th,  the  osseous  tissue ,-  6th, 
the  muscular  fibre ;  and  7th,  the  nervous  tissue.  Jlibliothcyue  Geimaniqite.  (*/V0.  8. 

The  arrangement  of  this  class  of  solids,  which  we  would  propose,  is  nearlj'the  same 
as  that  given  at  another  place.  (London  Medical  Repository  for  July,  1823.)  Employ- 
ing the  term  tissue  generically,  we  would  divide  the  compound  solids  of  the  body  into 
two  classes,  viz.  general  systems,  and  particular  textures. 

I.  GENERAL  SYSTEMS.    _Under  this  class  we  would  arrange,  1st,  the  cellular  system  ,- 
2d,  the  nervous  system,  which  comprehends  two  orders,  viz.  A,  the  involuntary  or  gang- 
lia! order  of  nerves,  or  the  system  of  the  great  sympathetic — and  K,  the  voluntary  order 
of  nerves;  3d,  the  muscular  system,  which  also  embraces  two  orders — JL,  the  involuntary 
order  of  muscular  fibres,  and  B,  the  voluntary  order  of  muscular  fibres  ;  4th,  the  vascu. 
lar  system  .-  this  system  has  four  orders,  viz".  A,  the  arterial  order  of  vessels  :  B,  the 
capillary  order ;    C,  the  venous  order  ;  D,  the  absorbent  vessels,  including  a,  the  lym- 
phatics, and  b,  the  lacteals. 

II.  PARTICULAR  TEXTURES.     This  class  includes,  1st,  the  mucous  textures  ;  3d,  serous 
textures  ;  Sd,  the  fibrous  textures,  embracing  the  fibrous,  the  fibro-cartilaginous,  and  the 
dermoid ;  4th,  the  cartilaginous  textures  ,•  5th,  the  osseous  textures  /  6ths  the  erectile  lex- 


APPENDIX. 


tures  ;  7th,  the  glandular  textures,  including  the  parenchyma  of  the  viscera  ;  8th,  the 
corneous  textures,  embracing  Jl,  the  pilous,  and  D,  the  epidermoid  textures. 

Proceeding  synthetically,  we  may  arrange  all  the  solids  of  which  the  animal  body  is? 
composed  after  the  following  manner. 

CLASS  I.     OR  ELEMENTARY  ANIMAL  SOLIDS. 


The  cellular  fibre.  The  nervous  fibre. 

The  muscular  fibre. 


CLASS  II.    SECONDARY  OR  COMPOUND  ANIMAL  SOLIDS. 
ORDER  I.     GENERAL  SYSTEMS.  ' 

The  cellular  system.^  The  nervous  system. 

Including  the  adipose  tissue.  Jl.   The  involuntary  or  ganglial  order 

of  nerves,  or  system  of  the  great  sym~ 
pathetic. 

JB.  The  voluntary  order  of  nerves. 
Ths  muscular  system.  The  vascular  system. 

A.  Involuntary  muscles.  Jl.  Arterial  vessels. 

B.  Voluntary  muscles.  J5.  Venous  vessels. 

C.  Absorbents. 

a.  Lymphatic  absorbents. 

b.  Lacteal  absorbents. 

ORDER  II.    PARTICULAR  TEXTURES, 

Mucous  textures.  Serous  textures. 

Erectile  textures.  Fibrous  textures, 

Jl.  The  fibrous. 

Ji.  Fibro-cartilaginous  textures* 
C.  The  clermoid  textures. 

Glandular  textures.  Corneous  texture. 

Cartilaginous  textures.  Jl.  The  epidermoid. 

Osseous  textures.  M.  The  Pilous. 


CLASS  III.     ASSOCIATED  OR  COMPLEX  ANIMAL  SOLIDS. 
ORDER  I.    OR&ANS  OF  NUTRITION. 

Digestive  organs.  Organs  of  absorption  and  circulation. 

Organs  of  respiration  and  assimilation.   Organs  of  secretion  and  animal  heat, 

ORDER  II.     ORGANS  OF  RELATION. 

Organs  of  sensation.  Organs  of  voluntary  motion* 

ORDER  III.  ORGANS  OF  REPRODUCTION. 

Organs  of  generation  in  both  sexes. 


Of  Sensibility  and  Contractility. 

Note  D. 

Sensibility. — The  phenomena  classed  by  the  author  under  this  property  of  Animal 
Life,  at  p.  19  and  20,  are  evidently  refcrrible  only  to  organic  contractility,  \vith  which 


OF  SENSIBILITY,  7 

r.ll  classes  of  animals  are  endowed,  and  which,  in  the  lowest  orders  and  in  some  vege* 
tables,  assumes  the  appearance  of  sensibility.  In  these,  however,  we  have  no  reason 
to  infer  the  presence  of  sensibility,  merely  because  they  contract  under  the  influence 
rfa  stimulus;  for  the  contraction  may  take  place  without  the  existence  of  this  property, 
from  the  effect  produced  by  the  stimulus  upon  the  organization  of  the  contracting-  part. 
Indeed  we  cannot  suppose  that  sensibility  is  present  where  the  parts  generally  observed 
to  be  instrumental  in  its  production  are  not  found  to  exist ; — a  sensation  cannot  be  sup- 
posed to  be  produced  where  there  neither  is  an  organization  suitable  to  receive,  a. 
channel  to  convey,  or  p.n  organ  to  perceive  an  impression.  We  should,  therefore,  limit 
this  term  to  those  phenomena,  which  the  author  arranges  under  that  of  perceptibility. 

With  this  limitation,  sensibility  may  be  called  the  function  of  sensation,  and  a  property 
peculiar  to  the  animal  kingdom.  The  sensations  are  derived  through  the  medium  of 
the  senses,  and  of  the  nerves,  which  are  distributed  to  certain  parts  of  the  body,  and 
which  communicate  with  the  encephalic  centre.  On  this  centi-e  the  existence  of  sensi- 
bility chiefly  depends  :  the  ramifications  of  its  nerves,  or  the  subordinate  portions  of- it, 
being  also  parts  of  the  apparatus  requisite,  but  not  giving  rise  to  this  property.  As  we 
ascend  in  the  scale  of  creation,  and  as  we  perceive  the  senses,  and  the  organs  of  voli- 
tion in  more  intimate  relation  with  this  nervous  mass — the  encephalon — so  we  find  sen- 
sibility becoming  more  perfect,  until,  in  man,  it  reaches  an  extent  greatly  surpassing 
that  in  which  we  observe  it  in  any  other  animal. 

In  man,  and  perhaps,  in  the  more  perfect  animals,  the  modes  of  sensibility  seem  to 
vary.  These  modes  may,  however,  be  divided  into  two  conditions,  as  they  are  more  oif 
less  active  ;  namely,  conscious  or  active  sensibility,  and  inconscious  or  passive  sensi- 
bility :  the  former  relates  to  these  impressions,  either  from  within  or  from  without, 
which  give  rise  to  perceptions  or  ideas,  the  latter  to  those  that  are  frequently  produced 
upon  the  senses  and  upon  the  ramifications  of  the  cerebral  nerves,  and,  owing  either  to 
habit  or  the  want  of  due  attention  to  them,  are  not  perceived  by  the  mind.  In  this  lat- 
ter mode  of  sensibility,  the  organ  receiving,  and  the  channel  conveying,  the  impression, 
perform  their  offices,  but  the  mind  either  is  not,  at  the  time  when  the  impression  is 
made,  in  a  state  to  receive  it,  or  receives  it  so  imperfectly,  from  its  weakness  or  its 
transient  nature,  as  not  to  give  rise  to  consciousness.  This  mode  does  not  necessarily 
imply  a  difference  in  the  degree  of  sensibility,  but  a  condition  in  which  it  exists,  owing 
either  to  its  being  excited  by  other  impressions,  or  to  its  enjoying  repose  from  being 
exhausted  at  the  time  when  the  impression  is  made ;  it  is  a  state  to  which  the  highest 
manifestations  of  sensibility,  as  well  as  the  lowest,  may  be  occasionally  subject.  It  is, 
however,  merely  a  relative  mode  of  this  property,  and  the  relation  subsists  entirely  be- 
tween the  state  of  the  cerebral  organ  which  perceives,  and  the  force  and  duration  of  the 
impression  made  upon  the  organ  of  sense.  Thus  when  the  sensibility  is  actively  occu- 
pied with  a  particular  object,  and  an  impression  is  made  at  the  same  time  upon  a  dif- 
ferent organ  from  that  through  which  the  perception,  with  which  the  mind  is  engaged, 
was  conveyed  ;  the  second  impression  may  affect  the  senses  in  an  evident  manner,  and 
even  so  as  to  influence  volition,  yet  we  may  be  inconscious  of  its  operation,  and  no  ac- 
tive perception  may  result  from  it.  If,  however,  the  second  impression  be  stronger  or 
more  vivid  than  the  first,  or  if,  from  various  circumstances  besides,  it  should  excite  the 
cerebral  functions,  active  sensibility  or  consciousness  is  the  result. 

As  sensibility,  according  to  this  view  of  the  subject,  is,  in  its  active  state,  aterm  mere- 
ly expressive  of  consciousness  in  the  entire  range  of  this  very  generally  diffused  faculty 
of  the  nervous  system ;  and  as  this  faculty  is  evidently  dependent  upon  this  system,  es- 
pecially on  the  more  complex  part  of  it  which  holds  relation  with  surrounding  objects  ; 
and  also  as  we  have  no  reason  to  attribute  the  possession  of  this  part  of  the  nervous  sys- 
tem, to  the  very  lowest  orders  of  animals,  particularly  to  the  class  Radials,  so  we  must 
conclude,  that,  although  a  property  of  animal  life,  its  higher  grades  are  not  possessed 
by  all  animals.  It  may  be  also  stated,  that  active  sensibility,  being  considered  as  ex- 
pressive of  the  consciousness  of  the  whole  class  of  sensations,  and  all  the  intellectual 
and  moral  operations,  varies  in  its  extent  throughout  the  animal  kingdom,  according  as 
those  manifestations  are  more  or  less  numerous  and  perfect.  How  far  the  passive  mode 
of  sensibility,  or  that  unattended  by  consciousness,  may  be  the  property  of  a  lowest 
orders  of  animals,  is  difficult  to  say.  We  may,  however  infer,  that,  as  this  condition  of 
sensibility  may  take  place  without  an  active  exertion  of  this  property  in  the  highest 
animals,  so  it  may  result  from  a  less  perfect  endowment  of  sensibility  in  the  lower;  ami 
as  this  mode  may  require  a  less  complex  apparatus  for  its  production,  inasmuch  as  its 
relations  are  more  simple,  so  It  may  be  possessed  by  animals,  whose  organization  and 
manifestations  do  not  permit  us  to  conclude  that  they  are  capable  of  evincing  sensibility 
in  its  more  perfect  and  active  conditions.  The  relations  which  this  form  or  mode  of 
sensibility  hold  with  the  numerous  instincts  of  animals,  must  be  evident  to  all  who  con- 


g  APPENDIX. 

siderthe  subject.  The  relations,  however,  which  evidently  subsist  between  that  form 
of  sensibility,  called  organic  sensibility  by  Bichat,  and  the  animal  instincts,  are  much 
more  numerous,  distinct,  and  intimate. 

Organic  Sensibility  refers  to  those  sensations  which  are  produced  in  different  degrees 
of  intensity,  owing  to  the  existence  of  certain  conditions  of  those  viscera  which  are  im- 
mediately subservient  to  the  preservation  of  the  individual  and  the  species — to  nutrition 
and  reproduction,  and  which  are  not  immediately  subjected  to  the  influence  of  volition. 
The  conditions  of  the  parts  exciting-  sensibility  are  very  various,  and  are  the  result  of 
irritations  arising  from  the  presence  of  a  stimulus,  of  unnatural  actions  supervening  in 
particular  systems  or  textures,  and  of  the  deficiency  of  that  stimulus  or  influence  to 
which  particular  viscera  have  become  accustomed.  Many  of  the  changes  preceding 
this  class  of  sensations,  seem  to  interest,  in  the  first  instance,  the  ganglial  class  of  nerves ; 
but,  owing  to  the  intimate  relation  existing  between  this  part  of  the  nervous  system  and 
the  voluntary  or  sentient  part,  the  impression  or  change  is  propagated  to  the  brain. 
This  is  the  only  essential  difference  which  subsists  between  this  and  the  other  forms  of 
sensibility.  It  is  the  brain  which  perceives  in  them  all ;  and,  although  stimuli,  or  the 
defect  of  stimuli,  may  give  rise  to  certain  phenomena  possessing  the  characters  of  the 
higher  manifestations  of  this  property,  in  the  organs  appropriated  to  the  preservation  of 
the  organic  system,  independently  of  the  sensorium,  consciousness  or  the  more  perfect 
form  of  sensibility,  cannot  form  part  of  the  results. 

Organic  sensibility  may  be  active  or  passive — it  may,  or  it  may  not,  be  attended  with 
consciousness ;  and  even  the  inconscious  mode  of  it  may  indirectly  impel  to  action,  or 
give  rise  to  many  of  the  manifestations  or  instincts  which  characterize  the  lower  ani- 
mals, owing  to  the  ganglial  centres,  either  from  their  organization  or  connexions,  or 
from  both,  performing  a  greater  extent  of  functions  than  generally  falls  to  their  share. 
I^  therefore,  the  passive  form  of  organic  sensibility  may  propel  to  action  without  con- 
sciousness or  the  sensorial  sensibility  being  excited  in  these  animals,  we  may  also  ac« 
count  in  the  same  manner,  for  many  of  the  instinctive  functions  being  performed  when 
we  cannot  trace  them  to  the  influence  of  a  cerebral  organ.  Of  all  the  conditions  of 
sensibility,  its  active  organic  form  is  the  least  under  the  controul  of  the  mental  energies 
of  the  individual  in  which  this  form  of  sensibility  is  developed.  It  also,  in  all  its  modes 
of  existence,  more  intimately  interests  the  existence  of  the  individual  than  the  other 
forms  of  sensibility, — it  involves  a  feeling  instinctive  of  life  or  death  in  all  its  active  ma- 
nifestations. 

From  this  it  will  be  readily  seen,  how  close  a  connexion  exists  between  organic  sen- 
sibility and  the  animal  instincts :  it  does  not  belong  to  our  plan  to  trace  the  connexion 
In  all  its  relations. 

Of  sensibility,  generally,  we  may  observe  that,  in  the  human  species,  it  is  very  varia- 
ble ;  in  some  persons  it  is  very  much  exalted,  in  others  very  obtuse.  It  is  vivid  in  early 
life  and  in  youth  ;  after  the  age  of  manhood,  it  gradually  diminishes ;  as  old  age  advan- 
ces, it  decreases  rapidly;  and,  in  persons  who  have  attained  a  great  age,  it  is  present  in 
the  lowest  grade,  in  which  we  find  it  in  the  species. 

Contractility  is  essentially  a  vital  phenomenon,  and  it  is  the  result  of  a  change  in  the 
relative  position  of  the  molecules  composing  the  solids  of  a  living  body.  This  property 
may  be  divided  into  the  following  grades,  commencing  with  the  lowest,  it  being  the 
most  generally  diffused  throughout  nature  : — 

1.  Insensible  Organic  Contractility,  or,  that  usually  denominated  tone  or  tonicity.   This 
grade  of  contractility  is  not  confined  to  the  animal  kingdom ;  it  is  a  property  of  vegeta- 
bles, and  of  animals  not  possessed  of  a  heart.   It  is  diffused  throughout  the  tissues.  The 
vascular  system  possesses  it  in  the  most  eminent  degree  ;  and  it  may  be  viewed  as  the 
result  of  the  vital  influence  with  which  the  structures  are  endowed  ;  it  is  more  or  less 
perfect  as  the  vital  energy  is  perfect,  and  it  disappears  with  the  extinction  of  this  prin- 
ciple.   It  is  a  property  of  the  tissues  and  of  the  vessels,  which  is  more  or  less  exerted  in 
all  the  vital  operations ;  in  the  circulation,  the  secretions,  nutrition,  and  absorption. 
The  ganglial  or  organic  class  of  nerves  seem  to  be  instrumental  in  its  production  and 
preservation,  in  the  animal  kingdom. 

2.  Sensible  organic  contractility^  or  irritability,  is  that  inherent  property  of  contraction 
which  exists  in  a!l  muscular,  and  in  some  other  textures.     It  is  excited  by  the  applica- 
tion of  a  variety  of  irritants.     It  seems  to  depend  upon  the  ultimate  distribution  of  the 
nervous  substance  to  these  parts,  and  chiefly  upon  the  nerves  proceeding  from  the 
ganglia. 

Both  these  species  of  organic  contractility  seem  to  result  from  one  species  of  influ- 
ence with  which  animal  bodies  are  endowed ;  they  are  the  proximate  result  of  vitality, 
and  merely  differ  from  each  other  owing  to  the  intimate  structure  of  the  parts  in  which 


OF  ORGANIC  SYMPATHY.  g 

they  arc  seated,  and  to  tUe  extent  to  which  each  of  the  parts  evincing  their  presence  is 
supplied  with  ganglial  ramifications. 

3.  Cerebral  Contractility  is  the  contraction  occasioned  by  the  will  in  voluntary  mus- 
cles. It  takes  place  only  in  such  muscular  parts  as  have  nerves  proceeding  from  the  en- 
cephalon,  or  rather  from  the  medulla  oblongata  and  spinal  cord,  terminating  in  their 
structure,  and  is  the  result  of  this  conformation  and  connexion  with  these  large  nervous 
masses. 

The  first  and  second  species  of  contractility  result  from  the  ganglial  distributions  and 
influence,  the  third  from  the  superaddition  of  the  nerves  of  voluntary  motion. 

Whilst,  therefore,  sensibility,  in  its  more  perfect  grades,  is  the  function  of  the  sensa- 
tions, is  chiefly  confined  to  certain  parts  and  textures  of  the  body,  and  is  dependent 
upon  the  part  of  the  nervous  system  of  which  the  encephalon  is  the  centre,  contractilty 
exists  throughout  the  whole  animal  structures,  although  in  different  grades,  and  is, 
with  the  exception  of  the  third  species,  or  grade  of  its  existence,  entirely  independent 
of  sensibility  and  volition  : — contractility  is  a  general  expression  of  life,  sensibility  of 
the  higher  functions  only  of  this  principle. 


Of  Sympathy. 
Note  E. 

Baglivi  attributed  the  sympathies  to  membranous  connexion  ;  Bordeu  to  the  cellular 
tissue ;  Willis  and  Vieusens  to  the  agency  of  the  nerves ;  and  Whitt  and  Broussais 
chiefly  to  the  brain.  Rega  divided  the  sympathies  into  those  of  sensibility  and  those  of 
contractility — a  division  which  has  much  to  recommend  it.  Bichat  offered  some  very 
excellent  observations  on  the  relations  subsisting  between  them  and  the  different  parts 
of  the  nervous  system  :  but,  although  these  observations  were  calculated  to  lead  to  a 
more  correct  arrangement  of  the  sympathies  than  had  been'formerly  offered,  it  has  not 
come  to  our  knowledge  that  any  has  appeared  founded  on  a  better  basis  than  that  in- 
dicated in  the  observations  of  Bichat. 

In  a  preceding  note,  we  suggested  that  the  sympathies  should  be  arranged  into  the 
reflex  and  the  direct — the  former  arising  through  the  instrumentality  of  the  sensorium, 
the  latter  taking  place  independently  of  it,  through  the  means  of  the  ganglial  nerves, 
and  chiefly  of  those  which  are  distributed  to  the  blood-vessels  and  which  form  com- 
municating cords  between  the  viscera. 

With  a  view  to  the  illustration  of  the  latter  class  of  sympathies,  viz.  those  which  are 
direct,  and  chiefly  consist  of  the  sympathetic  actions  of  organic  life,  we  shall  offer  a 
few  remarks. 

When  it  is  considered  that  the  ganglial  nerves  alone  supply  the  blood-vessels  and 
the  secreting  organs  and  surfaces  ;  that  they  accompany  these  vessels  to  the  utmost 
limits  of  their  ramifications ;  that  they  communicate  very  freely  with  each  other,  and 
\vith  their  chief  centre — the  semilunar  ganglion  ;  that  they  give  rise  to  numerous  plex- 
uses which  render  the  connexion  between  them  still  more  intimate  ;  and  that  they  hold 
a  close  relation  with  the  rest  of  the  nervous  system  through  means  of  communicating 
nerves, — the  mutual  dependence  of  action  between  the  chief  organs  of  the  body,  in, 
health  and  in  disease,  may  be  easily  explained :  if,  moreover,  it  be  granted  that  the 
most  important  vital  phenomena,  as  digestion,  assimilation,  circulation,  secretion,  ani- 
mal heat,  generation,  8cc.  (see  the  note  on  the  fwictions  of  the  ganglial  system,")  in  short, 
that  life  itself  with  all  those  manifestations  of  it  now  particularised,  and  which  have 
been  usually  called  organic,  result  form  the  influence  exerted  by  this  part  of  the  ner- 
vous system,  through  the  instrumentality  of  the  vessels,  upon  the  fluid  they  contain, 
and  in  some  measure  reciprocally  by  this  fluid  upon  these  nerves  ramified  in  the  pa- 
rietes  of  the  vessels,  and  upon  the  ganglia  themselves  through  which  it  must  of  course 
circulate,  the  agency  of  this  system  in  the  production  of  the  class  of  sympathies  under 
consideration  must  be  evident.  From  this  view  of  the  subject  and  from  taking  into 
account  the  modifying  operation  of  similar  textures,  the  related  action  of  various  or- 
gans, and,  under  certain  circumstances,  the  combined  influence  and  re-action  of  the 
sensorium,  the  numerous  relations  and  connexions  of  healthy  function  and  of  disorder- 
ed action  may  be  more  satisfactorily  traced. 

When  one  organ  qr  system  of  parts  is  excited  to  increased  action,  or  when  its  oper>- 
tions  are  diminished  or  obstructed,  we  perceive  all  the  other  parts  of  the  system  whirh 

B 


15  APPENDIX. 

communicate  yith  it,  througihthe  medium  of  the  gangial  system,  experiencing  a  modi- 
fication of  their  functions, — the  action  of  one  or  more  organs  having  always  an  evident 
relation  with  the  kind  and  degree  of  action  going  on  in  the  other.  In  these  cases  the 
relation  is  sufficiently  manifest ;  but  the  kind  and  degree  of  it  may  vary  very  greatly  be- 
tween different  organs.  And  the  relations  may  be  of  the  following  sorts,  as  the  vital 
energies  distributed  throughout  the  system  are  affected  in  degree  or  in  kind,  or  in  both 
ways  at  the  same  time. 

I.  Organic  sympathies  in  which  the  vital  energy  of  the  system  evinces  various  modifica- 
tions in  degree  and  distribution ;  but  in  -which  it  is  not  changed  in  kind, 

1.  Related  actions  may  be  characterised  by  a  due  proportion  of  a  healthy  degree  of 
the  vital  forces  of  the  whole  system  ;  but  owing1  to  the  application  of  an  exciting-  cause 
fo  one  organ  or  part,  or  to  two  or  three  organs,  these  forces  may  be  greatly  increased 
in  them ;  as,  however,  the  healthy  or  medium  quantity  of  the  vital  forces  of  the  body 
is  not  supposed  to  be  exceeded,  there  consequently  must  be  a  proportionate  diminution 
of  these  forces  throughout  the  other  parts  of  the  system*. 


*  "When  the  natural  functions  of  one  organ  is  simply  excited  without  being  diseased, 
the  functions  of  the  other  organs  with  'which  it.  holds  communication,  by  means  of  the 
ganglial  nerves,  undergoes  a  relative  degree  of  change,  for  the  excitement  of  a  viscus 
is  merely  an  exaltation  of  its  vitality  ;  and  as  we  exalt  the  vital  actions  in  one  or  more 
departments  of  the  entire  series,  we  diminish  them  throughout  the  rest  in  an  equal  pro- 
portion ;  the  excitement  being  frequently  greater  or  less  in  some  parts,  and  the  di- 
minution more  or  less  confined  to  others. 

If,  for  the  sake  of  illustration,  we  suppose  the  vital  energies  of  the  system  to  be  equal 
to  50 :  and,  through  means  of  the  organic  or  ganglial  nerves  to  be  distributed  as  fol- 
lows ;— to  the  stomach  and  intestines — 7 ;  to  the  heart,  vascular  system  and  lungs — 8 ; 
to  the  brain  and  voluntary  nerves — 7;  to  the  liver,  spleen  and  pancreas — 6 ;  to  the  gene- 
rative organs — 3  :  to  the  urinary  apparatus — 4 ;  to  the  surface  of  the  body — 3  :  to  the 
rest  of  the  body — 11 ;  we  may  consider  that  it  is  duly  proportioned.  But  if,  owing  to 
the  application  of  certain  excitants  to  one  or  more  organs,  as  to  the  stomach  and  intes- 
tines, we  exalt  the  proportion  bestowed  on  these  to  13,  we  shall  consequently  find  the 
brain  and  voluntary  nerves  possessing  only  5  ; — the  heart,  vessels  and  lungs  7  ; — the 
urinary  organs  3  ; — the  surface  of  the  body  2  ;  and  the  rest  of  tbe  body  experiencing 
the  loss  of  the  remaining  one.  If,  again,  we  excite  the  vital  forces  distributed  to  the 
heart  and  vascular  system,  until  they  amount  to  16,  we  shall  have  a  febrile  condition  of 
the  system  in  its  simplest  form,  and  all  the  other  organs  will  suffer  a  diminution  in 
proportion :  the  stomach  will  only  equal  4,  and  so  on  in  proportion.  But  the  vital 
forces  of  the  heart  and  blood-vessels  may  equal  16 ;  and,  owing  to  the  arteries  of  the 
brain  experiencing1  an  undue  proportion  of  this  increase,  this  organ  may  at  the  same 
time  equal  10 ;  or,  instead  of  this  increase  falling  to  the  lot  of  the  cerebral  vessels, 
those  of  the  viscera  may  be  similarly  augmented  whilst  those  of  the  remaining  or- 
gans may  be  proportionally  diminished :  in  such  cases  we  have  a  less  simple  result; 
but,  nevertheless,  the  increase  of  the  circulating  functions  is  followed  by  an  equal  di- 
minution of  the  secreting.  Viewing1  the  sympathetic  connexion  of  function  in  ano- 
ther direction,  we  shall  suppose  that  the  excited  state  of  vital  action  takes  place  in 
secreting  organs;  in  this  case  the  nutritive  and  other  animal  operations  are  diminished 
in  an  eq*  "*\  degree.  Or  we  shall  suppose  that  the  excitement  commences  in  the  capil- 
laries of  an  organ,  from  the  presence  of  an  irritating  cause,  that,  owing  to  these  ves- 
sels being  supplied  with  ramifications  of  the  same  order  of  nerves  which  supply  the 
heart  and  vascular  system  generally,  the  excitement  extends  more  or  less  throughout 
this  system ;  and  that,  in  comsequence  of  the  continuity  of  this  order  of  nerves,  and 
their  very  frequent  reticulaiions  and  inosculations,  not  only  do  the  heart  and  arteries 
experience  the  excitement  produced  at  a  part  of  the  extreme  circumference,  but  the 
\vhole  body  suffers  a  relative  degree  of  derangement,  and  hence  evinces  all  the  phe- 
nomena of  sympathetic  fever.  Thus  the  capillaries  of  a  particular  organ  are  excited  ; 
the  excitement  extends  more  or  less  g-enerally  throughout  the  vascular  series,  and  the 
nutritive  and  secreting  functions  are  diminished  in  proportion  as  the  actions  of  the 
heart  and  arteries  are  increased.  Many  collateral  views  of  this  subject  may  be  adduced, 
and  many  of  its  connexions  traced,  as  well  as  various  modifying  influences,  both  in  and 
out  of  the  body,  appreciated,— all  tending  to  establish  the  positions  that  it  is  chiefly  to 
the  ganglial  nerves  we  ought  to  attribute  the  manifold  phenomena  of  related  action 
v.-hich  we  observe  in  the  animal  econemy.  At  this  place  we  have  only  considered  one 
of  the  genera  belonging  to  this  class  of  sympathies,  namely,  that  which  comprehends 
the  most  simple  of  the  related  actions — those  which  supervene  in  the  system  without 
nn  increase  or  diminution  of  the  whole  amount  of  the  vital  energies  with  which  the 


OF  UAlilT,  11 

In  this  order  of  sympathies  there  are  three  relations  to  be  observed,  which  actually 
more  or  less  obtain  and  constitute  the  essence  of  the  subject,  or  the  actual  condition  of 
the  animal  functions  under  consideration  :  1st,  the  relation  may  respect  the  increased 
actions  subsisting  in  two  or  more  organs  ;  2d,  it  may  be  viewed  between  the  increased 
functions  of  one  part  and  the  diminished  functions  of  another  ;  and  3d,  it  may  regard  the 
diminished  functions  observed  in  those  parts  which  do  not  participate  in  the  excitement ; 
the  relation  being  most  immediate  in  the  first,  and  least  so  in  the  third  of  these  forms. 

2.  The  sympathetic  or  related  actions  may  be  attended  with  a  diminution  of  the  sum 
of  the  vital  energies  throughout  the  system.  In  this  case  the  different  relations  pointed 
out  above,  may  nevertheless  exist,  or  one  or  two  of  them,  may  only  be  remarkable  ; 
the  chief  difference  here  being  that  the  sympathies  of  this  order  are  generally  induced 
by  agents,  which,  while  they  diminish  the  entire  sum  of  vital  energy,  act  more  deci- 
dedly upon  particular  organs  or  systems  of  parts. 

3."  The  sympathetic  operations  may  be  characterized  by  a  somewhat  greater  amount 
of  the  vital" energies  of  the  whole  body.  In  this  order  of  sympathies  the  three  rela- 
tions particularized  above  also  subsist ;  for  although  the  entire  sum  of  vital  actions  may 
be  greater  than  what  is  usually  bestowed  on  the  system,  it  may  be  so  much  increased 
in  some  organs  as  to  be  greatly  "diminished  in  others.  This  condition  of  functional  sym- 
pathy seldom  continues  long-  until  it  subsides  to  the  first,  or,  from  exhaustion  of  the  vi- 
tal energies,  to  the  second  order  just  now  particularized. 

II.  Organic  sympathies  in  -which,  in  addition  to  various  modifications  in  degree  and  dis- 
fribution,  the  vital  energy  of  tlie  system  suffers  a  change  in  its  kind. 

1. — Sympathetic  actions  in  which  the  general  amount  of  the  vital  forces  is  natural  in 
degree  but  vitiated  or  modified  in  kind,  the  relation  being  evident — 1st,  mutually  be- 
tween  these  functions  which  are  increased ;  2nd^  between  the  actions  which  are  augmen- 
ted and  these  which  are  diminished  :  and  3d,  between  those  only  which  are  diminished. 

2. — Sympathies  ill  which  the  entire  sum  of  vital  energy  is  both  reduced  in  degree 
and  modified  in  kind ;  the  relation  between  its  distribution  in  the  various  organs  being 
the  same  as  just  now  pointed  out. 

3. — Sympathies  in  which  the  amount  of  the  whole  vital  energy  is  both  heightened  in 
degree  and  modified  in  kind.  In  this  order  the  distributed  and  the  relations  to  which 
such  distribution  gives  rise,  are  the  same  as  already  adduced. 

The  application  of  this  classification,  and  of  the  views  wliich  it  embraces  to  rnedi-* 
^ine,  must  appear  evident. 


Of  Habit. 
Note  F. 

^Ve  have  before  said  that  the  effects  of  habit  upon  our  voluntary  organs  are  very 
different  from  thoee  which  result  from  its  influence,  on  the  viscera  of  organic  life.  This 
difference  is,  however,  chiefly  in  degree  ;  for,  sensibility,  as  there  is  eveiy  reason  to 
suppose,  from  its  most  vivid  state  of  existence  until  it  merges  in  contractility,  and  in  its 
various  modes  of  manifestation,  differs  chiefly  in  degree,  and  as  is  bestowed  in  some 
.  one  mode  and  degree  to  all  the  organs  of  the  body,  although  it  be  more  particularly 
limited  to  one  of  their  tissues,  and  also  as  the  influence  of  habit  is  chiefly  exerted  upon 
the  sensibility  of  the  system  ;  so  it  follows  that  it  modifies  more  or  less/all  the  animal 
and  organic  functions,  although  it  acts  in  the  most  manifest  manner  on  those  organs 
which  are  in  the  closest  relation  with  the  sensorium  or  functions  of  the  brain.  Thus 
the  stimulus  which  excites  the  action  of  the  sensorium  produces  a  much  less  intense  ef- 
fect by  repetition,  but  the  repeated  employment  of  the  same  food,  or  of  the  same  pur- 
gative, does  not  materially  less  excite  the  action  of  the  viscera,  to  which  they  are  respec- 
tively applied.  As  the  'influence  of  habit,  therefore,  is  chiefly  an  the  sensibility  of 
the  system,  so  it  follows,  that,  when  the  organic  sensibility  of  the  involuntary  organs 
is  repeatedly  excited,  it  is  then  that  the  diminished  effects  of  the  excitant  upon  them 


body  is  endowed.  The  other  kinds  of  related  function  have  been  pointed  out  in  the 
above  arrangement  of  this  class  of  sympathies  ;  and  we  cannot  farther  allude  to  them 
here  ;  indeed  it  would  be  much  beyond  our  limits  to  consider  fully  the  different  kinds 
of  sympathy  in  their  manifold  relations ;  we  have  illustrated  one  more  particularly,  be- 
cause of  its  importance,  and  of  its  having  been  very  generally  overlooked. 


12  APPENDIX. 

are  most  manifest— -that  the  more  sensibility  of  our  organs  is  called  forth,  the  more  is 
the  influence  of  habit  remarkable.  Those  stimuli,  however,  which  act  chiefly  and  the 
most  exclusively  on  the  contractility  of  the  textures,  and  those  organs  principally  con- 
sist in  the  exertion  of  this  principle  of  life,  have  their  operations  the  least  impaired  by 
repeated  employment ;  indeed,  in  many  instances  those  organs  have  their  functions  in- 
creased and  rendered  more  perfect  by  frequent  exertion.  Hence,  independently  of 
degree,  is  the  chief  difference  in  the  influence  of  habit  on  the  voluntary  organs  of  the 
body. 


Of  Inflammation, 
Kote  G, 

As  the  author  has  taken  occasion  to  give  his  opinion  respecting  the  proximate  cause 
of  inflammation,  we  shall  follow  his  example,  and  briefly  illustrate  the  view  which  we 
entertained  of  it,  and  published  in  a  thesis  on  rheumatism,  in  1815,  and  more  recently 
in  a  paper  on  the  functions  of  the  ganglionic  nerves,  contained  in  the  London  Medical 
depository  for  May  1822.  On  these  occasions  we  defined  active  inflammation  to  be  the 
result  of  a  morbidly  excited  state  of  the  gangliul  nerves  supplying  the  capillaries  of  the 
affected  part,  or  a  derangement  arising  from  the  unnaturally  exalted  condition  of  these 
nerves  on  which  the  functions  of  the  capillaries  depend. 

One  of  the  chief  inquiries  respecting  its  nature,  and  physiological  relations,  is  whe- 
ther this  exalted  or  excited  state  of  these  nervous  fibrillae  is  one  of  simple  excitement 
or  no, — whether  the  natural  functions  of  these  fibrillie  be  merely  increased  above  their 
healthy  or  ordinary  pitch,  or  whether  or  no  they  are  also  otherwise  changed.  In  the 
definition,  we  said  morbidly  or  unnaturally  excited,  thereby  indicating  that  the  func- 
tions or  influence  of  these  nerves  are  not  only  simply  increased,  but  also  increased  dif- 
ferently from  what  we  observe  in  a  healthy  part,  from  the  application  of  a  stimulus* 
both  as  respects  duration  and  kind  of  action. 

1.  As  respects  the  duration  of  this  exalted  state.     In  the  vascular  phenomena  dis- 
played by  blushing,  or  by  the  application  of  a  gentle  stimulus,  the  effects  soon  subside 
after  the  removal  of  the  exciting  cause ;  because  the  nervous  influence  exerted  on  the 
capillaries  is  simply  increased  without  the  mode  or  habitude  of  operation  being  changed. 
But  before  we  can  farther  explain  the  duration  of  excitement  we  must  secondly  inquire 
into  its  kind. 

2.  When  a  stimulus  or  irritant  is  applied  to  a  part,  its  action  seems  to  be  first  upon 
the  ganglial  fibrillae  supplying  the  capillaries.     The  vital  influence  of  these  fibrillas 
being  excited,  the  actions  of  the  capillaries  which  they  supply  are  consequently  increas- 
ed.    There  is,  however,  every  reason  to  suppose,  that  the  increase  of  this  influence  is 
not  simple,  that  it  is  not  only  changed  in  degree,  but  also  modified  in  kind.     The  irri- 
tant seems  to  impress  the  nervous  fibrillse  of  the  part,  or  of  the  system  more  general!}', 
in  such  a  manner  as  to  prevent  it  from  returning  to  its  natural  state  for  a  very  considera- 
ble time,  or  even  at  all ; — the  excited  action  is  induced,  it  continues,  and  the  longer  it 
continues  the  less  it  is  disposed  to  return  to  its  healthy  condition.    But  wherefore  does 
the  excitement  continue  ?     To  this  we  may  answer,  either  because  the  irritating  or  ex- 
citing cause  continues  to  operate  by  its  actual  presence,  or  more  frequently  because 
the  impression  made  by  it,  while  it  changed  the  degree  of  nervous  influence,  also  m6- 
rlified  its  state  of  existence,  and  kind  of  operation  on  the  vessels  themselves,  and  the 
fluids  which  they  contain.     It  is,  therefore,  owing  to  the  impression  of  causes,  or 
changes  thereby  produced  in  the  kind  as  well  as  degree  of  influence  exerted  by  the 
yiervons  fibrilla?,  that  we  are  to  impute,  1st,  the  duration  of  the  excitement ;  and  2dlyj 
the  different  phenomena  which  capillary  derangements  or  inflammations  present.    A 
few  of  these  phenomena  we  shall  particularize. 

1.  Uneasy  sensations  from  its  lowest  degree  until  it  amounts  to  acute  pain.  Uneasy  sen- 
sation alone  may  be  considered  one  of  the  primary  phenomena  following  the  operation 
of  the  exciting  cause  ;  or  rather  one  of  the  manifestations  characteristic  of  that  kind  or 
state  of  excitement,  or  deranged  influence  of  the  nervous  fibrillse,  forming  the  first  se- 
ries of  the  changes  induced  in  the  affected  part ;  and  it  may  be  farther  kept  up  by  the 
subsequent  changes  induced  in  the  capillaries  by  the  disordered  state  of  the  nervous 
influence,  of  which  state  it  is  itself  one  of  the  manifestations.  When  the  uneasy  sensa- 
tion amounts  to  pain,  it  may  be  owing  either  to  the  degree  of  change  with  which  the 
influence  of  the  nervous  fibrill<E,  and  through  it  the  action  of  the  capillaries  are  imbued, 


OV  INFLAMMATION.  13 

ar  it  may  arise  in  consequence  of  the  ganglia!  system  of  nerves  communicating  their 
disordered  excitement,  which  has  commenced  in  them  to  these  cerebral  nerves  with 
which  they  are  associated  in  the  textures :  for,  as  we  have  already  stated,  the  ganglia! 
nerves  being  plentifully  distributed  to  the  capillary  vessels  in  every  part  and  tissue  of 
the  body,  must  consequently  communicate  freely,  and  come  closely  in  contact  with  the 
sentient  or  voluntary  class  of  nerves,  especially  in  those  textures  which  are  abundantly 
supplied  with  them.  By  means'of  this  connexion  the  excited  functions  of  the  former  class 
is  very  probably  communicated  to  the  sentient  extremities  of  the  other  class,  and  the  sen- 
sibility of  the  latter  being  thus  excited,  is  still  farther  promoted  by  the  derangement  of 
the  capillaries  which  the  former  nerves  induce.  But  this  phenomenon  of  inflammation 
jhay  not  result  exclusively  in  the  one  manner  or  in  the  other.  It  may  take  place  in  both 
ways  in  the  same  part,  or  in  the  one  or  the  other  more  or  less  partially.  In  those  vis- 
cera which  are  imperfectly  supplied  with  the  cerebro-spinal  nerves,  the  first  alternative 
may  be  adopted.  Indeed,  in  these  textures  very  considerable  inflammation  may  exist 
xvithout  any  other  modification  of  pain  than  uneasy  sensations  being  felt ;  whereas,  in 
the  other  organs,  whose  supply  of  sentient  nerves  is  considerable,  the  second  explana- 
tion may  be  entertained ;  whilst  in  some  viscera  both  modes  of  accounting  for  this  mor- 
bjd  manifestation  may  be  resorted  to.  But  whatever  manner  of  explanation  should  be 
adopted,  according  to  the  distinction  just  now  stated,  it  ought  not  to  be  forgotten  that 
this  particular  manifestation  of  disease  is  modified,  throughout  its  manifold  grades,  by 
the  texture  of  the  part  effected,  and  by  the  exciting  and  other  causes  to  which  it  is 
indebted  for  its  existence  and  progress. 

According  to  this  view  of  the  subject  it  will  be  observed,  that  we  consider  the  pain 
of  inflammation  as  originating  in,  or  caused  by,  the  condition  of  the  particular  influence 
or  function  performed  by  the  fibrillse  or  the  ganglia!  system  of  nerves,— as  a  state  of 
these  nerves  produced  deranged  action  of  the  capillaries  to  .vhich  they  are  distributed, 
and  exciting  or  otherwise  disturbing  the  sensibility  and  functions  of  the  other  class  of 
p.erves  with  which  they  become  associated  in  many  of  the  textures  ;  whereas  the  most 
acute  pains,  those  which  are  not  necessarily  attended  with  inflammation,  and  very  sel- 
dom give  rise  to  it,  as  those  accompanying  tic  douloureux,  trismus,  the  various  forms  of 
spasmodic  diseases,  and  some  other  painful  disorders  which  it  is  unnecessary  to  desig- 
nate, originate  exclusively  in  the  fibrillse  of  the  cerebro-spinal  nerves.  This  appears  to 
be  an  important  and  fundamental  distinction  in  pathology,  and  one  which  we  have 
adopted,  not  without  much  reflection  and  pathological  research.  It  accounts  for  a  very 
frequent  phenomena,  namely,  the  presence  of  the  most  violent  pain  when  there  are  no 
appearances  o{  inflammation  either  during  its  existence  or  after  its  subsidence.  It  shows 
also  that,  with  the  exception  of  the  countenance,  and  one  or  two  other  parts,  excite- 
ment commencing  in  the  cerebro-spinal  or  sentient  nerves,  has  but  little  immediate  in- 
fluence upon  the  capillary  circulation ;  and  it  also  points  out,  that  whatever  influence 
these  nerves  may  possess  over  the  circulation  and  the  vital  phenomena  allied  to  it, 
it  is  only  by  means  of  exciting  the  ganglial  nerves  distributed  to  the  structure  of  the 
part,  and  to  the  blood-vessels  ramifying  in  it,  that  any  such  influences  can  be  exerted. 
This,  it  may  be  siiown,  were  it  necessary  to  speculate  respecting  final  causes,  is  a  pro- 
vision requisite  to  the  preservation  of  the  textures,  and  consequently  of  the  animal  body; 
for  if  the  circulation  throughout  the  different  textures  and  organs  were  immediately  under 
the  dominion  of  the  sentient  nerves,  and  removed  from  that  of  the  ganglial,  we  should 
have  not  only  all  the  phenomena  which  more  strictly  belong  to  it,  but  all  the  vital  ma- 
nifestations of  nutrition,  secretion,  animal  heat,  &c.  which  are  under  the  influence  of 
the  gang-Rome  system,  subjected  to  continual  derangement  from  the  various  impulses  of 
the  will  and  the  passions.  As  these  functions,  on  which  the  preservation  of  the  indivi- 
dual depends,  are  under  the  dominion  of  another  and  less  fluctuating  influence,  they  are 
less  endangered  by  the  numerous  causes  of  change  by  which  they  are  constantly  sur- 
rounded, and  with  which  they  hold  frequent  communication.  But,  although  tiie  func- 
tions which  are  immediately  vital  are  those  which  belong  the  province  of  this  system, 
they  may  be  acted  upon  either  generally  or  partially  through  the  medium  of  the  ner- 
vous system  of  relation,  or  of  animal  life,  which  system  has  its  own  particular  functions 
to  perform,  and  these  occasionally  exert  no  mean  influence  over  those  of  the  former 
class. 

2.  Redness,  or  the  injection  of  the  capillaries  -with  red  blood.  This  phenomenon  has  crea- 
ted much  discussion,  It  would  be  foreign  to  our  plan  to  enter  at  this  place  upon  the 
different  arguments  which  have  been  entertained  respecting  it.  We  shall  merely  state 
our  own  opinion  as  to  its  nature. 

The  vital  influence  of  the  ganglial  class  of  nerves  is,  as  we  have  just  now  stated,  mor- 
bidly increased  in  the  effected  part,  especially  as  respects  these  nerves  distributed  more 
directly  to  the  capillaries.  We  observe,  on  every  occasion  in  the  animal  economy,  that 


14  APPENDIX. 

when  the  vital  actions  of  capillary  vessels  are  increased,  the  vessels  themselves  become 
larger,  more  fully  injected,  and  circulate  a  larger  quantity  of  blood.  Now,  if  we  allow 
that  an  increase  in  degree  forms  one  part  of  the  change  in  the  vital  influence  bestowed 
on  the  capillaries  by  the  ganglial  neives,  it  therefore  follows  that  a  proportionate  change 
in  the  calibre  of  the  minuter  vessels  should  result  from  such  increase  as  it  usually  does 
on  those  occasions  when  it  supervenes  in  a-natural  manner. 

In  shert  that  one  of  the  changes  constituting  the  acute  stage  of  inflammation  is  an  ex- 
alted state  of  the  vital  influence  distributed  by  the  ganglial  nerves  to  the  capillaries  of 
the  part ;  an  exalted  state  of  this  influence  always  increases  the  action  and  caliber  of  the 
capillaries,  therefore  both  must  be  increased  whenever  this  condition  of  vital  influences 
constitutes  a  part  of  the  primary  derangement. 

But  it  has  been  argued,  that  when  an  inflamed  capillary  is  viewed  in  a  microscope, 
the  current  of  blood  in  it  is  slower,  instead  of  being  quicker,  than  natural.  This,  how. 
ever,  arises,  as  we  have  stated  on  another  occasion,  from  the  inflamed  capillarv  vessels 
admitting  a  greater  number  of  red  globules,  and  thus  giving  rise  to  the  optical  illusion 
of  their  slower  motion,  when  in  fact  they  actually  move  much  quicker  than  when  the 
vessel  admits  a  single  globule  at  a  time,  and  when  the  entire  space  between  each  glo- 
bule moving  in  the  vessel  can  be  seen.  Another  objection  has  been  urged  in  support 
of  the  l^pothesis  of  relaxation  or  debility  of  the  vessels,  namely,  that  the  exposed  ca- 
pillaries contract  upon  the  application  of  an  irritant;  but  so  do  all  irritable  parts,  and  so 
do  all  parts,  to  a  greater  or  less  extent,  which  are  supplied  with  the  vital  influence.  la 
these  experiments  it  has  not  been  considered,  because  it  was  unfavourable  to  the  hypo- 
thesis, that  the  irritant  acts  in  a  two-fold  capacity ;  it  excites  irritable  fibres  to  contraction, 
and  it  constringes  the  structure  of  the  part.  These  experiments  also  appear  generally 
to  have  been  performed  under  circumstances  of  disorder,  and  at  a  period  when  the  in- 
flammation was  passing  into  that  stage  which  is  constituted  by  a  greater  or  less  exhaus- 
tion of  the  increased  influence  which  formerly  actuated  the  capillaries. 

3. — Increase  of  the  animal  heat  in  an  actively  inflamed  part. — We  have  contended  in 
another  place  that  animal  heat  is  the  result  of  the  vital  influence  of  the  ganglial  nerves 
upon  the  vessels  and  the  fluid  circulating  through  them,  and  that  the  heat  of  the  whole 
body  or  of  a  single  part  has  an  intimate  relation  with  the  degree  of  Influence  which  this 
system  of  nerves  exerts,  especially  that  part  of  it  supplying  the  vessels,  either  as  res- 
pects the  body  generally,  or  as  regards  the  part  more  particularly  effected.  If  this  po- 
sition be  granted,  it  cannot  be  denied  that  the  augmented  heat  in  inflammation  is  de- 
rived from  the  same  source,  namely,  the  increased  influence,  on  the  vessels  of  the  af- 
fected part,  of  that  particular  system  of  nerves  on  which  the  production  of  animal 
heat  chiefly  depends.  (See  the  Note  on  the  functions  of  the  ganglionic  system  of  nerves. ) 

From  this  it  will  be  seen  that,  we  consider  inflammation,  in  its  various  forms  and  stages 
to  originate  in,  and  to  depend  upon,  the  altered  kind  and  degree  of  influence  which 
the  ganglial  system  of  nerves  exerts  on  the  capillaries  of  the  part : — that  whenever  this 
influence  is  greater  than  natural,  the  action  of  the  capillaries  is  greater  than  natural, 
and  whenever  it  is  below  the  healthy  condition,  these  vessels  are  equally  deficient  in  a 
requisite  degree  of  action  ; — that  the  kind  of  influence  is  changed  as  well  as  the  degree 
of  influence  ;  and  that,  as  inflammation  originates  in  this  class  of  nerves,  it  may  be  con- 
sidered as  a  lesion  of  the  function  of  these  nerves,  and  therefore  occurring  more  fre- 
quently in  those  tissues  which  are  the  least  supplied  with  an  additional  and  a  compen- 
sating influence  from  the  other  parts  of  the  nervous  system  :  hence  the  reason  that  in- 
flammation is  very  seldom  seen  in  the  muscular  fibre,  to  which  the  cerebral  nerves  are 
so  plentifully  distributed,  and  hence  the  probable  cause  that  it  so  frequently  attacks 
cellular  parts,  or  those  which  are  essentially  cellular  in  their  nature. 

At  this  place  we  have  merely  considered  a  few  of  the  physiological  relations  of  acute 
inflammation,  in  a  brief  and  an  imperfect  manner.  The  other  points  connected  with 
this  subject  which  might  be  discussed,  but  which  are  more  strictly  pathological,  are — 
1st,  the  different  characters  of  acute  inflammation,  according  to  the  textures  in  which 
it  is  seated  ;  2d,  the  stages  of  inflammation,  in  relation  to  the  individual  tissues,  down 
through  their  numerous  grades  until  they  reach  the  lowest ;  3d,  inflammation  in  which 
the  influence  bestowed  on  the  vessels  by  the  ganglial  nerves  is  more  or  less  exhausted 
or  destroyed ;  4th,  the  state  of  the  venous  capillaries  and  absorbents  in  the  different 
stages  and  grades  of  inflammation  ;  5th,  the  varying  phenomena  which  this  species  of 
derangement  presents  according  as  it  is  modified  by  constitutional,  peculiarities  ;  6th, 
the  different  manifestations  of  inflammation  arising  from  the  nature  of  its  exciting 
causes,  Sec.  These  and  other  relations  of  this  fundamental,  and  most  important  part  of 
pathology,  will  be  considered  in  an  extended  manner  on  another  occasion. 


OF  THE  FUNCTIONS  OF  THE  GANGLIAL  SYSTEM.       J5 

Of  the  Ganglia!  or  Great  Sympathetic  System  of  Nerves. 
Note  H. 

It  would  be  incompatible  with  the  limits  of  these  notes  to  point  out  the  anatomical 
peculiarities  and  connexions  of  this  important  system,  or  even  to  enter  upon  a  length- 
ened discussion  of  their  functions.  We  shall  therefore  conn' ne  ourselves  to  the  state- 
ment of  the  general  propositions,  at  which  \ve  arrived  on  the  latter  part  of  the  subject, 
and  which  were  contained  in  a  paper  on  the  functions  of  the  ganglionic  system  of  nerves, 
read  to  the  Medical  society  of  London  in  1820. 

It  may  be  proper  to  remark,  that  these  inferences  were  deduced  from  numerous  dis- 
sections of  individal  subjects  belonging  to  the  different  classes  of  animals,  and  from  se- 
veral experiments  made  in  order  to  ascertain  the  extent  of  function  which  this  system  of 
nerves  performs.  The  observations  made  on  these  occasions  we  will  soon  have  an  op- 
portunity of  describing  in  a  particular  manner. 

1.  The  ganglial  class  of  nerves  is  to  be  found  throughout  every  order  of  the  animal 
creation,  commencing  with  th'e  lowest,  the  Radiatse,  and  ascending  to  the  highest. 

2.  The  ganglial  nerves  is  the  only  part  of  the  nervous  system  with  which  the  lowest 
orders  of  animals  are  provided. 

3.  As  we  ascend  the  scale  of  creation  another  class  of  nerves  is  superadded,  namely, 
the  encephalic,  with  which  the  ganglial  nerves  are  connected.     In  the  higher  animals 
possessing  only  the  ganglial  nerves,  we  perceive  the  ganglial  placed  on  or  near  the  oeso- 
phagus gradually  assuming  more  and  more  the  characters  of  a  brain,  and  becoming 
more  evidently  connected  with  organs  of  sense.     We  also  observe  the  nervous  cords 
between  the  ganglia  arranging  themselves  more  and  more  in  the  manner  of  a  spinal 
marrow,  as  the  locomotive  organs  become  more  distinct  from  those  of  nutrition  ;  thus 
rendering  the  steps  of  gradation  between  the  animals  provided  only  with  the  lowest  or 
simplest  form  of  nervous  ganglia,  and  those  possessed  both  of  ganglia  and  of  animal  or 
voluntary  system  of  nerves,  almost  imperceptible. 

4.  The  nerves  which  are  given  oft  from  the  encephalic  mass  and  from  the  spinal  mar- 
row evince  different  characters  as  soon  as  these  parts  of  the  nervous  system  become  dis- 
tinct from  the  ganglia ;  and  even  in  progress  towards  the  fullest  distinction  which  they 
ultimately  attain,  the  difference  between  both  the  classes  of  nerves  becomes  still  more 
manifest 

5.  In  all  the  more  perfect  animals,  the  ganglia  and  the  various  distributions,  as  far  as 
they  can  be  traced  by  the  senses,  even  when  aided  by  powerful  glasses  and  minute  dis- 
section, are  entirely  different  from  the  nerves  derived  from  the  brain  and  spinal  cord, 
in  their  texture,  colour,  consistence,  mode  of  ramification  and  distribution  ;  and  they 
supply  very  different  organs  and  textures  from  those  to  which  the  cerebral  and  spinal 
nerves  are  distributed. 

6.  Not  only  in  the  lowest  order  of  animals  may  the  ganglial  nerves  be  traced  before 
the  voluntary  or  sentient  class  of  nerves  come  into  existence,  but  also  in  the  embryos  of 
the  higher  animals  the  ganglia  may  be  distinguished  before  any  traces  of  a  spinal  mar- 
row or  of  a  brain  can  be  perceived. 

7.  The  ganglial  nerves  cannot  be  supposed  to  originate  in  either  the  brain  or  spinal 
marrow—let,  because  they  are  observed  in  the  lowest  animals,   who  possess  neither 
brain  nor  spinal  cord ;  2dly,  because  they  may  be  distinguished  in  embryos  before  ei- 
ther the  one  or  the  other  nervous  mass  can  be  traced  and  Sdly,  because  they  arc- 
never  wanting    in  the  fcctal  state,  whereas  not  only  have  the  brain  and  spinal  marrow 
been  individually  wanting,  but  the  same  foetus  has  been  found  entirely  without  both. 

8.  The  difference  between  this  class  of  nerves  and  those  of  animal  life  is  not  evinced 
only  by  their  respective  appearances,  by  the  general  distribution  of  the  former  through- 
out the  animal  creation,  by  the  history  of  the  embryal  foetus,  and  by  the  phenomena  ex- 
hibited by  monsters,  but  it  is  also  apparent  from  the  very  different 'effects  which  are  ob- 
served in  them,  as  respects  both  the  living  and  dead  subject,  on  the  application  of  va- 
rious excitants  and  re-agents*. 


*  The  difference  between  these  nerves  is 


nerves  is  very  remarkable  on  the  application  of  gal- 
vanism ;  for,  whilst  we  found  that  the  voluntary  nerves  could  be  excited  with  a  few 
plates,  two  hundred  could  produce  only  a  slightly  perceptible  effect  upon  the  parts 
more  immediately  supplied  with  fibrills  from  the  semilunar  ganglion.  When  gajranism 
v/as  applied  to  this  ganglion  itself  in  the  recently  killed  animal,  but  little  appreciable 


16  APPENDIX,  \ 

9.  The  points  of  dissimilarity  just  now  instanced  evidently  show  that  the  gangiia 
find  their  numerous  distributions  form  an  independent  system  in  the  animal  economy  : 
and  that  as  one  thing  cannot  be  said  to  torm  a  part  of  another  thing  from  which  it  is 
essentially  different,  so  the  ganglia  and  their  ramifications  cannot  be  supposed  to  form 
a  part  of  the  nervous  system  of  animal  life,  or  that  which  presides  over  the  intellectual 
and  locomotive  functions. 

10.  The  independence  of  the  ganglial  system  may  be  farther  demonstrated  in  many 
of  the  lower  animals,  and  in  the  young-  of  the  most  perfect  animals;  for  in  these  both 
the  brain  and  spinal  cord  may  be  destroyed  gradually ;  and,  provided  the  function  of  res- 
piration  he  not  entirely  put  a  stop  to,  the  functions  of  circulation  and  secretion  will 
still  be  continued. 

11.  That  the  dependence  of  t!  is  system,  and  the  extent  of  the  peculiar  influence 
which  it  exerts  in  the  animal  ecu;  omy  is  farther  proved  in  the  most  perfect  animals,  by 
the  effects  of  disease  upon  the  brain  and  spinal  marrow,  either  of  which  may  be  de- 
stroyed to  a  very  great  extent,  and  these   organs  only  which  they  supply  be  deprived 
of  their  functions,  while  those  viscera  which  receive  the  ramifications  of  the  ganglial 
system  will  continue  to  perform  their  actions  without  evincing1  much  disorder,  unless 
that  part  of  the  nervous  mass  which  actuates  the  contraction  of  the  respiratory  muscles 
becomes  involved  in  the  disease. 

12.  The  ganglia  supply  with  fibrills:  all  the  organs  of  digestion,  assimilation,  circu- 
lation and  secretion. 

13.  The  heart  is  chiefly  supplied  with  nerves  coming  directly  from  this  class  of  nerves, 

14.  These  nerves  form  a  closely  reticulated  envelope  around  the  arteries  of  the 
throat  and  abdomen,  and  around  the  vena  portse  :  they  may  be  traced  in  the  larger 
branches  of  arteries  in  the  extremities,  and  of  the  head,  until  they  reach  the  brain  it- 
self. 

15.  The  arteries  throughout  the  body,  and  indeed  all  the  other  parts  of  the  vascular 
system,  receive  nerves  directly  from  no  other  source  than  from  the  ganglia. 

16.  The  same  system  supplies,  in  a  demonstrable  manner,  all  the  involuntary  muscles, 
and  it  seems  to  send  flbrillae  to  several  of  the  voluntary  muscles,  especially  to  those 
about  the  centre  of  the  body.     It  is  also  liberally  distributed  to  all  the  secreting  glands 
and  surfaces*. 


effect  was  produced  either  on  the  vessels  with  which  it  is  intimately  connected,  or  upon 
the  stomach  and  upper  portion  of  the  small  intestines.  In  the  majority  of  instances, 
however,  these  parts  seemed  to  be  in  a  more  contracted  state  while  under  the  g-alvanic 
influence.  When  the  influence  of  the  battery  (of  two  hundred  plates)  was  directed 
upon  the  semilunar  ganglion  of  a  young  cat,  it  evinced  symptoms  of  pain  and  distress, 
and  several  irregular  contractions  of  the  diaphragm  supervened.  The  effects  of  galva- 
nism were  also  tried  on  some  of  the  other  ganglia,  but  they  evinced  no  appearance  of 
being  oppressed  by  it  in  the  dead  subject,  and,  in  the  living,  the  result  was  equivocal. 
On  these  occasions  we  experienced  great  difficulty  from  the  want  of  proper  assistance. 
We  propose,  however,  to  repeat  and  to  extend  these  experiments ;  and  we  expect  emi- 
ment  coadjutorship  in  their  performance,  and  the  assistance  of  a  very  powerful  galvanic 
battery. 

*  If,  therefore,  the  existence  of  these  nerves  is  every  where  demonstrable  in  the 
centre  of  the  system,  and  even  throughout  its  radius,  until  we  arrive  at  the  superficies 
or  extreme  parts  of  the  body,  where  it  may  be  supposed  that  they  must  elude,  from 
the  nature  of  their  organization,  the  detection  of  the  senses,  it  cannot  be  contrary  to 
the  uniform  operations  of  nature,  and  to  the  many  analogies  she  presents,  to  infer,  that 
they  are  distributed  to  the  extreme  ramifications  of  the  arteries,  upon  whose  more  con- 
siderable branches  they  are  readily  demonstrable.  And  if  they  are  also  shown  to  exist 
in  some  voluntary  mus'clcs,  may  they  not  be  considered  to  be  present  in  all,  bestowing 
upon  these  muscles  their  peculiar  energies,  the  nerves  of  animal  life  producing  only 
the  functions  which  usually  result  from  this  class  of  nerves,  in  addition  to  those  arising 
from  the  involuntary  influence  or  vital  energy  which  these  muscles  derive  from  the  gan- 
glia and  tJffcir  distributions. 

It  may  be  mentioned,  that  consistently  with  the  opinions  we  entertained  respecting 
the  independence  of,  and  extent  of  the  functions  performed  by,  the  ganglia  and  their 
distributions,  that  we  assign  the  terms — ganglial  system,  organic  system  of  nerves,  vital 
system  of  nerves,  synonymously ;  and  we  use  the  terms- — cerebro-spinal  system  of  nerves, 
voluntary  nerves,  and  sentient  system,  also  synonymously.  To  this  there  may  be  some 
objections;  but  as  we  did  so  in  the  original  paper,  we  wish  hot  to  alter  it. 


OF  THE  FUNCTIONS  OF  THE  GANGLIAL  SYSTEM.       jy 

17.  From  the  manner  in  which  the  ganglial  nerves  invest  the  arteries  proceeding 
into  the  brain,  and  reasoning  from  analogy,  we  infer  that  they  accompany  the  arteries 
throughout  the  substance  of  this  viscus,  as  in  other  organs  of  the  body,  and  that  they 
influence  its  vascular  functions  in  a  similar  manrier. 

18.  The  chief  origin  or  centre  of  the  ganglial  system  is  generally  situated,  in  all  the 
higher  orders  of  animals  especially,  about  the  middle  of  the  body,  and,  under  the  name 
of  the  semilunar  ganglion,  it  sends  off  branches,  which  form  plexuses;  these  present 
modified  characters,  as  respects  their  external  appearance  and  confirmation,  in  their 
course  to  their  different  organs  which  they  supply. 

This  central  ganglion  more  immediately  supplies  the  organs  of  digestion,  chylifac- 
tion  and  circulation,  where  the  expenditure  of  the  vital  Influence  is  greatest,  and^sends 
communicating  branches  to  the  subordinate  ganglia  and  plexuses. 

19.  The  external  characters  of  the  ganglia  and  of  their  plexuses  and  ramifications 
vary  considerably  in  different  situations,  both  as  respects  their  colour,  their  external 
form  and  internal  structure. 

20.  The  subordinate  ganglia,  while  they  seem  to  receive  a  reinforcement  of  vital  in- 
fluence from  the  centre  ganglion,  modify  that  influence,  and  generate  an  accession  to 
it,  suitable  both  in  kind  and  degree  to  the  functions  of  the  organs  which  they  are  des- 
tined to  actuate. 

21.  This  class  of  nerves  sends  off,  and  receives  cords  of  communication  between  the 
brain  and  its  subordinate  organs,  and  between  the  spinal  marrow  and  its  distributions  : 
this  seems  to  give  rise  to  a  reciprocal  communication  of  influence  between  the  organs 
of  nutrition,  &.c.  and  those  of  relation,  and  a  mutual  dependence  of  function,  which  is 
more  intimate  and  apparent  as  we  rise  in  the  scale  of  creation, — the  independence 
of  the  former  class  of  functions  becoming  more  evident  as  we  descend,  and  the  younger 
the  animal  is  as  we  ascend  the  scale. 

22.  The  extent  and  mode  of  communication  between  different  parts  of  the  volun- 
tary nerves,  and  the  ganglia  and  their  distributions,  vary  very  considerably. 

23.  As  this"  class  of  nerves  are  so  entirely  different  in  their  appearance,  structure, 
properties,  and  mode  of  distribution,  and  as  they  supply  very  different  organs  from 
those  which  receive  the  encephalic  class  of  nerves;  so  it  maybe  inferred  that  they 
perform  essentially  different  functions,  although  these  functions,  in  the  higher  animals 
more  particularly,  are  in  close  relation  with  those  of  the  rest  of  the  body. 

24.  As  it  is  demonstrated,  that  the  ganglial  or  vital  nerves  supply  the  heart,  that 
they  surround  and  are  ramified  in  the  arteries  throughout  their  distribution  :  that  no 
part  of  the  vascular  system  receives,  in  a  direct  manner,  any  voluntary  nerves  ;  and  as 
it  is  reasonable  to  suppose  that  this  provision  does  not  exist  without  accomplishing  im- 
portant purposes  in  the  animal  economy,  ahd  as  the  fibres  of  involuntary  muscles  are 
evidently  supplied  from  the  same  source  ;  and,  farther,  as  we  cannot  suppose,  conform- 
ably to  the  laws  of  nature,  that  the  bare  coats  of  the  vessels,  and  particularly  of  the 
arteries,  without  such  a  provision,  could  be  possessed  of  any  vital  properties — so  we  in- 
fer that  all  the  vital  phenomena,  which  the  vascular  system  exhibits  throughout  the 
body,  are  under  the  direct  influence  of  this  class  of  nerves. 

25.  The  distribution  of  these  nerves  around  the  arteries,  and  the  manner  in  which 
their  nbrillze  penetrate  the  coats  of  these  vessels,  seem  to  evince  that  they  not  only 
impart  to  them  whatever  vital  properties  they  may  possess,  but  that  they  moreover  pro- 
duce those  changes  on  the  blood  to  which  it" is  subject,  whilst  flowing  in  the  vessels, 
and  many  of  those  phenomena  which  this  fluid  presents  soon  after  it  has  been  taken 
from  the  body. 

26.  It  is  also  reasonable  to  suppose  that  the  influence  exerted  by  this  system  on  the 
capillaries,  and  the  additional  influence  which  its  ramifications  bestow  on  the  substance 
of  the  viscera,  combine  to  produce  the  secretion,  in  secreting  organs  and  surfaces,  and 
nutrition  throughout  the  textures  of  the  body.     Hence,  that  the  varied  phenomena 
displayed  by  the  blood  itself,  by  the  functions  of  digestion,  secretion*,  assimilation, 


*  No  experiment  instituted  with  the  intention  of  showing  the  influence  of  the 
nerves  given  off  from  the  brain  and  spinal  cord  upon  secretion,  can  prove  the  reality 
of  such  influence.  Because  these  orders  of  nerves  are  not  ramified  upon  the  vascular 
system,  nor  do  they  even  supply  the  capillary  vessels.  This  is  a  wise  provision ;  for  if 
the  heart  and  blood-vessels  were  directly  under  the  influence  of  the  voluntary  nerves, 
in  any  of  its  divisions,  this  system  would  be  constantly  deranged  by  it,  and  vascular 
disease  be  incomparably  more  frequent  and  fatal,  Such  experiments,  were  they 
instituted  with  thd*utmost  precautions,  could  prove  no  more  than  has  been  shown  bv 
those  of  Dr.  Phillips  and  Leirallois,  which  at  most  evince  that  the  vital  functions  resul'- 

e 


;(g  APPENBDt 

Sec.  result  from  fhe  Condition  of  the  influence  which  this  System,  in  its  centre  and  dis« 
tributions,  is  instrumental  in  generating  in  the  vessels  and  fluids  which  they  contain. 
May  not  a  vital  influence  or  atmosphere,  as  it  were,  be  produced  from  the  extreme 
fibrillaB  of  this  system,  or  between  them  ad  the  coats  of  the  capillary  vessels,  which 
influence,  whatever  may  be  its  state  of  existence,  impresses  the  fluid  circulating-  in 
these  vessels  in  a  manner  which  produces  different  effects,  according1  to  its  excess  or 
defect,  or  according  to  other  modifications  to  which  it  may  be  subject — in  health  and 
disease,  owing  to  the  numerous  causes  of  change  to  which  it  is  exposed  ? 

27.  The  separation  from  the  blood  of  the  materials  which  supply  the  waste  of  the 
textures,  or  give  rise  to  their  growth,  is  the  office  of  this  system,  which  imparts  its  in- 
iiuence  to,  and  operates  through  the  medium  of  the  vascular  system. 

28.  The  vital  manifestations  of  the  veins  and  absorbents  (with  the  exception  of  the 
vena  ports)  arise  from  the  distribution  of  the  system  of  nerves  to  the  minute  arterial  ca- 
pillaries supplying  their  parictes,  and  to  the  adjoining  textures;  and,  probably,  from 
the  distribution  of  minute  fibrillse  to  their  tunics — an  org-anization  which,  although  it  can- 
not  be  demonstrated,  may  nevertheless  exist,  and  thus  the  vital  manifestations  of  the 
venous  system  may  more  readily  be  explained. 

29.  The  ganglial  nerves  sheathe  the  vena  portse  throughout  its  course  in  the  liver ;  and, 
from  the  very  abundant  manner  in  which  they  supply  this  particular  vein,  from  the  con- 
formation of  the  vein  itself  both  as  respects  its  coats  and  connexions  with  the  texture 
of  the  liver,  and  with  the  other  vessels,  and  from  the  character  of  the  blood  conveyed 
to  and  from  it,  we  conclude, — that  it  is  through  the  vital  influence  bestowed  on  the 
vena  portse  by  the  ganglial  nerves,  assisted  with  that  belonging  to  the  other  vessels  and 
the  textwe  of  this  viscus,  that  the  changes  induced  in  the  blood  returned  from  the  di- 
gestive canal  and  its  allied  viscera,  and  containing  a  large  proportion  of  absorbed  mate- 
rials, are  produced ;  and  that  the  secretion  of  the  bile  results  from  the  same  influence, 
partly  as  a  consequence  of  these  previous  changes,  and  partly  as  its  independent  act 
exerted  both  upon  the  extreme  ramifications  of  the  vena  portse,  and  of  the  hepatic  ar- 
tery, this  secretion  consequently  proceeding  from  both  the  kinds  of  blood  contained  by 
these  vessels. 

30.  That  this  system  of  nerves,  by  means  of  the  influence  derived  from  its  principal 
nnd  subordinate  sources,  and  numerous  distributions,  and  exerted  upon  the  vascular 
system,  generates  animal  heat  througout  the  body ;  and  that  the  production  of  animal 
heat  takes  place  in  a  manner  analogous  to  the  process  of  nutrition  and  secretion.* 

31.  The  state  of  animal  heat,  like  other,  secretions,  will  be  greatly  modified  by  the 
condition,  both  as  respects  kind  and  degree,  of  the  vital  influence  of  the  ganglial  sys- 
tem, and  by  the  state  of  the  blood  on  which  this  influence  is  exerted,  which  state  will 
have  a  double  operation  in  modifying  the  result.     (See  the  note  on  animal  heat.) 

32.  It  appears  probable,  from  the  effects  of  several  agents  upon  the  voluntary  and 
other  muscular  parts,  when  applied  immediately  to  the  ganglial  or  vital  system  of  nerves, 
from  the  general  distribution  of  this  system  to  the  capillary  arteries,  and  from  the  cir- 


ing  from  the  ganglial  or  vital  class  of  nerves  may  be  influenced,  in  the  more  perfect 
animals,  by  the  destruction  of  a  part  of  the  nervous  system  with  which  they  have  held, 
and  with  which  they  always  hold,  a  more  or  less  intimate  relation  ;  and  that  the  same 
nerves,  which,  during  health,  have  conveyed  a  natural  stimulus  to  the  vital  activity  of 
particular  organs,  may  convey  an  artificial  one  :  and  when  the  natural  stimulus  or  ex- 
citant is  removed,  o"r  the  subordinate  function  annihilated,  the  operations  to  which  it 
is  requisite,  in  the  highest  animals,  must  languish  and  ultimately  decay. 

Indeed,  it  is  only  reasonable  to  suppose,  that  the  involuntary  nerves,  as  they  commu- 
nicate with  the  organic  or  vital  nerves,  convey  a  natural  stimulus,  or  influence  to  the 
latter,  which,  if  they  were  deprived  of  it,  after  its  continued  and  uninterrupted  influx, 
the  vital  functions  of  the  organs  enjoying  this  additional  influence,  would  necessarily 
languish,  or  even  be  overturned  if  the  privation  took  place  suddenly  and  completely. 
If,  however,  it  were  brought  about  gradually,  it  might  be  produced  to  a  great  extent, 
and  in  many  animals  completely. 

*  The  experiments  of  insulating  a  limb  by  dividing  all  the  voluntary  nerves  and  ar- 
teries, excepting  one  arterial  trunk,  performed  by  Mr.  Brodie,  in  order  to  ascertain  the 
effects  produced  upon  the  generation  of  heat  in  'the  lirnb,  prove  this  proposition,  and 
could  not  fail  of  giving  rise  to  what  was  actually  observed.  For  the  ganglial  or  vital 
nerves  supplying  that'vessel  could  not  be  completely  detached  as  long  as  any  of  the 
coats  of  the  artery  remained  undivided. 


OF  THE  FUNCTIONS  OF  THE  GANGLIAL  SYSTEM-       49 

cumstance  of  its  supplying  and  actuating  the  involuntary  muscles,  that  it  also  bestows 
its  proper  influence  upon  those  which  are  voluntary,  and  that  thus  it  gives  rise,  in  both, 
to  the  phenomenon  of  muscular  parts  usually  called  irritability;  the  different  manifes- 
tations of  this  property,  as  it  is  displayed  in  voluntary  and  involuntary  muscles,  resulting 
from  the  accessory  supply  of  the  cerebro-spinal  nerves  which  the  former  class  of  mus- 
cles receives.  (See  Note  F.  F.) 

33.  That  the  ganglial  system  appears  to  be  productive  of  certain  obscure  sensations 
or  instinctive  impulses  (organic  sensibility)  which  are,  by  means  of  the  communicating 
branches  of  nerves  between  this  system  and  the  cerebro-spinal  masses,  propagated  to 
the  latter,  and  from  the  influence  they  there  excite,  become  the  cause  of  several  mani- 
festations, which  more  immediately  proceed  from  this  latter  part  of  the  nervous  system. 

34.  This  operation  of  the  ganglial  system  on  the  functions  of  the  cerebro-spinal  sys- 
tem is  more  remarkable  when  the  former  is  influenced  by  disease  or  by  a  stimulus  which 
is  unnatural  either  in  kind  or  degree ;  or  even  when  a  natural  excitant,  to  which  this 
system  has  been  accustomed,  is  withheld,  whether  such  excitant  operates  either  direct- 
ly or  indirectly,  or  in  both  ways,  as  the  supply  of  food,  Sec. 

35.  The  communicating  branches  of  nerves  between  the  chief  ganglia  of  the  abdo- 
minal and  thoracic  cavities,  whilst  they  are  the  medium  of  communication  between  the 
ganglial  and  cerebro-spinal  systems,  intercept  or  moderate,  by  means  of  the  subordi- 
nate ganglia  placed  in  their  course,  the  influences  proceeding  from  one  system  to  the 
other.     Thus  it  is  that  the  ganglia  in  the  neck  and  chest  moderate  the  influence  of  the 
functions  of  the  brain  on  the  heart,  and  that  no  impulse  of  the  former  can  reach  the  lat- 
ter but  through  the  medium  of  the  ganglia ;  and  so  little  are  the  ganglia  influenced  by 
the  operations  and  excitements  of  the  brain,  that  organic  sensibility  is  only  slightly  pro- 
duced by  them.     If,  therefore,  the  impulses  of  passion  and  volition  produce  but  an  ob- 
scure effect  upon  the  ganglia  and  their  chief  centre,  it  is  not  to  be  wondered  at,  that  the 
galvanic  influence — which  must  be  very  considerable  to  equal  the  impulses  of  volition — 
should  act  comparatively  in  a  very  slight  and  almost  insensible  manner  upon  this  system, 

36.  The  ganglia  on  the  communicating  branches  between  the  internal  ganglia  and 
the  spinal  cord,  intercept  the  impulses  proceeding  through  this  latter  channel ;  and 
while  they  thus  moderate  the  operations  of  both  the  brain  and  spinal  marrow  upon  the 
internal  ganglia!,  they  seem  to  generate  an  influence  suited  to  the  intermediate  place 
which  they  hold. 

37.  Irritations  of  the  ganglial  system  appear  to  act  in  a  slight  and  obscure  manner  up- 
on the  voluntary  organs,  through  the  medium  of  the  communicating  or  conducting  bran- 
ches between  this  system  and  the  spinal  cord;  and,  but  for  the  ganglia  on  their  course, 
the  irritations  of  the  former,  and  the  impulses  of  the  latter  and  of  the  brain,  would  re- 
ciprocally act  in  a  manner  that  would  be  much  more  marked,  and  even  in  a  way  that 
would  be  injurious  to  the  whole  body. 

38.  The  influence  of  the  ganglial  on  the  cerebro-spinal  system,  is  more  marked  as 
the  developement  and  functions  of  the  former  system  predominate,  as  in  the  lo-vver  ani- 
mals and  in  the  foetus  of  those  which  belong  to  the  highest  orders.* 

*  The  following  outline  exhibits  a  view  of  the  extent  of  influence  which  we  have  at- 
tributed to  the  ganglionic  system  :  it  formed  a  part  of  the  contents  of  a  treatise  on  the 
anatomy,  physiology,  and  pathology  of  the  ganglionic  class  of  nerves,  &c.  the  publica- 
tion of  which  was  commenced  in  the  London  Medical  Repository,  but  was  discontinued 
in  order  that  it  might  appear  in  a  separate  and  extended  form. 

"PABT  I.  comprehends  the  following  sections  : — 1.  A  description  of  the  organs  ge- 
nerally called  nervous  ganglia. — 2.  An  examination  into  the  distribution  of  their  rami- 
fications, or  fibrillae,  as  far  as  that  has  been  determined,  either  by  my  own,  or  by  the  ob- 
servations of  others. — 3.  Reasons  against  the  usually  received  opinion,  that  they  consti- 
tute a  part  of  the  cerebral  and  spinal  nerves  ;  and  proofs  of  their  forming  a  distinct 
system  from  the  brain,  spinal  cord,  and  nerves  proceeding  from  these  sources. — 4.  An 
account  of  the  connexion  existing  between  the  ganglia  or  their  ramifications,  and  the 
nervous  system,  properly  so  called ;  and  the  mode  by  which  that  connexion  is  eifected. 
•5.  An  inquiry  respecting  what  viscera  and  textures  they  supply. — 6.  Proofs  from  the 
history  of  the  species,  and  from  comparative  anatomy,  that  they  form  the  first  eHbrt  of 
organization,  and  are  instrumental  in  the  production  of  the  other  textures. — 7.  Remarks 
respecting  their  state  during  the  formation,  progress,  and  decline  of  the  animal.— 8.  In- 
ferences from  the  preceding  inquiries. 

"  PABT  II.  The  functions  of  the  ganglia  considered— 1.  As  they  regard  the  vascular 
system,  on  which  they  are  chiefly  ramified — A.  Proofs  that  the  ganglia  are  the  primary 
and  chief  source  of  the  heart's  action — C.  Their  power  over  the  arterial  and  capillary 


2Q  APPENDIX. 

39.  As  the  ganglia  of  the  great  sympathetic  form  an  independent  system  presiding 
over  certain  functions  which  are  essentially  vital,  consequently  they  may  be  viewed  as 
the  system  and  seat  of  organic  life,  and  may,  therefore,  be  denominated  the  vital  system 
of  nerves,  whose  centre  is  the  semilunar  ganglion.* 

40.  It  seems  probable,  from  the  circumstances  of  a  separate  ganglion  or  plexus,  or 
both,  being  generally  assigned  to  each  important  secreting  or  animalizing  organ,  that  the 
centre  or  source  of  vital  influence  does  not  supply  the  whole  vitality  distributed  by  the 
ganglial  ramifications  to  the  individual  organs  and  textures ;  but  that  the  vital  influence 
proceeding  from  this  centre  is  reinforced  by  that  which  is  produced  by  the  subordinate 
ganglia,  and  is  not  only  reinforced,  but  modified  by  them,  and  by  their  distributions  in 
the  various  organs,  so  as  to  give  rise  to  the  specific  difference  of  function  which  each 
performs ;  and  that  the  vital  manifestations  of  particular  ganglia  are  still  farther  modified 
by  the  communicating  branches  between  them  and  the  cerebro-spinal  system,  the  ex- 
tent of  modification  being  relative  to  the  extent  to  which  the  nerves  of  this  latter  sys- 
tem either  communicate  with,  or  contribute  to  supply,  or  to  form,  the  individual  subor- 
dinate ganglia. 

Lastly.  The  vital  influence,  being  thus  produced  from  the  centre  of  the  body,  and" 
reinforced  and  modified  by  the  subordinate  ganglia,  allotted  to  the  individual  organs, 
accm-ding  to  their  functions",  is  propagated  along  the  distributions  of  the  system,  on  which, 
it  depends  and  is  inherent,  throughout  the  whole  body. 

systems  inquired  into,  and  the  irritability  of  the  latter  class  of  vessels  contended  for, 
and  shown  to  be  derived  from  this  cause — D.  Evidences  of  their  influence  over  the  se- 
creting viscera  and  textures,  a.  On  the  gastric  secretions  and  functions,  b.  Their  con- 
trol over  the  secretions  from  mucous  and  other  surfaces,  and  from  follicular  glands,  c- 
Over  the  biliary  and  pancreatic  secretions,  d.  Over  the  secretions  and  functions  of  the 
urinary  organs. — E.  Their  influence  on  the  mass  of  blood  circulating  through  the  heart 
and  blood-vessels,  a.  As  regards  the  changes  induced  in  this  fluid  during  respiration. 
b.  As  respects  the  phenomena  which  it  displays,  after  having  been  drawn  from  an  arte- 
ry and  vein  in  the  general  circulation,  during  various  states  of  the  system,  c.  The  power 
of  these  organs  in  the  production  of  animal  heat. 

«  2.  The  functions  of  these  organs,  viewed  in  connexion  with  the  muscular  fibres  of 
involuntary  motion. — 3.  The  probability  of  their  being  the  chief  source  of  irritability 
contended  for,  and  the  varying  characters  of  this  principle  explained,  as  it  is  displayed 
in  the  different  muscular  textures  and  capillary  vessels. — 4.  The  influence  of  the  brain 
and  spinal  cord,  upon  the  operations  of  the  organs  under  consideration,  viewed,  a. 
In  respect  to  the  manner  and  extent  in  which  the  former  affect  the  contractions  of  the 
heart.  6,  As  they  (the  voluntary  nerves)  ntay  affect  the  capillary  circulation  of  a  part, 
and  proofs  of  their  limited  influence  over  the  vascular  ramifications,  c.  With  regard 
to  the  small  extent  of  power  which  the  brain  and  spinal  cord  can  exert  over  the  func- 
tions of  digestion,  unless  through  the  medium  of  the  ganglions. — 5.  A  general  view  of 
the  phenomena  to  which  the  ganglial  ramifications  give  rise,  when  reinforced  by  the 
nerves  properly  so  called. — 6.  The  manisfestations  to  which  they  give  rise  in  the  infe- 
rior classes  of  the  animal  creation. — 7.  The  functions  of  the  ganglions,  as  they  regard 

the  generative  process,     a.  In  the  male.     b.  In  the  female 8.  Their  influence  in  the 

formation  and  nutrition  of  the  textures ;  and  in  the  progress  and  decay  of  the  animal, 
considered. — 9.  The  effects  produced  on  different  animals,  by  the  application  of  certain 

substances  to  the  expansion  of  these  organs 10.  The  consideration,  that  the  manifes- 

taions  essentially  vital  are  the  result  of  these  organs,  entertained,  argued  for,  and  ex- 
plained from  the  inferences  deduced  from  the  foregoing  sections. — 11.  A  general  view 
of  the  doctrines  contained  in  this  part  of  the  treatise. — (Land.  Med  Repos.  for  Jlfaij, 
1822.) 

*  Violent  blows  or  contusions  on  the  epigastric  region,  when  they  do  not  immediate- 
ly destroy  the  individual  subjected  to  them,  depress  in  a  very  remarkable  manner  the 
vital  energies  of  the  system.'  The  animal  heat  is  uncommonly  diminished ;  the  surface 
is  cold  and  pale  ;  the  pulse  slow,  and  scarcely  perceptible  ;  and  the  breathing  feeble 
and  very  slow.  An  analogous  effect  in  some  respects,  is  produced  by  concussion  of 
the  semilunar  ganglion,  as  that  which  follows  concussion  of  the  brain  :  in  the  former  the 
vital  or  organic  actions  are  either  exhausted  or  destroyed,  in  the  other  animal  or  volun- 
tary operations  only  are  suspended. 


THE  EFFECTS  OF  LONG  PROTRACTED  ABSTINENCE.  21 

TJie  Effects  of  long  protracted  Abstinence. 
Note  I. 

The  effects  of  protracted  abstinence  on  the  human  subject  are  well  illustrated 
by  the  following1  facts :— During- the  famine  which  desolated  certain  parts  of  France,  in, 
the  year  1817,  especially  during  the  months  of  April,  May,  and  June,  when  the  miser- 
able" inhabitants  had  exhausted  their  stock  of  provisions,  and  when  they  were  reduced 
to  live  on  herbaceous  vegetables  only  as  wild  sorrel,  nettles,  patience,  succory^  thistles, 
the  tops  of  beans,  the  sprigs  of  young  trees,  &c.  M.  Gaspard,  (Journ.  de  Physiol.  Eper. 
Al».  3.)  observed  that  a  general  serous  diathesis  prevailed,  or  universal  anasarcaof  the 
cellular  membrane,  without  ascites,  jaundice,  or  any  organic  lesion  of  the  liver,  or  of 
any  of  the  abdominal  viscera.  Many  women  experienced  an  interruption  of  the  catame- 
nia ;  and  a  reference  in  the  register  of  births  subsequently  to  the  communes  which  suf- 
fered from  the  famine,  showed  that  the  number  of  conceptions  was  less  by  more  than 
one  half,  during  the  three  calamitous  months  of  that  year,  than  during  the  same  months 
of  the  preceding  and  following  years. 

During  these  months  many  assuaged  their  hunger  by  eating  snails,  of  which  an  incre- 
dible number  was  destroyed  :  but  those  who  largely  partook  of  them  experienced  a  state 
of  stupor,  analagous  to  that  produced  by  belladonna. 

A  tradesman,  impelled  by  a  succession  of  misfortunes,  retired  to  a  sequestered  spot 
in  a  forest  in  Germany,  and  there  resolved  to  starve  himself  to  death.  He  put  his  de- 
termination in  force  on  the  loth  of  Sept.  1818  ;  and  was  found  18  days  afterwards  still 
living,  although  speechless,  insensible,  and  reduced  to  the  last  stage  of  debility.  A  small 


bushes  and  leaves.  On  the  17th  of  Sept.  (the  second  day)  he  complained  of  suffering 
from  cold ;  on  the  18th  he  mentioned  having  suffered  from  intolerable  thirst,  to  ap- 
pease which  he  licked  the  dew  from  the  surrounding  vegetables.  On  the  20th  he  found 
a  small  coin,  and  with  difficulty  reached  an  inn,  where  he  purchased  a  bottle  of  beer ; 
the  beer  failed  to  quench  his  thirst,  and  his  strength  was  so  reduced,  that  he  took  three 
hours  to  accomplish  the  distance,  which  was  about  two  miles.  On  the  22d  he  discover- 
ed a  spring  of  water,  but  though  tormented  with  thirst,  the  agony  which  the  cold  water 
produced  on  his  stomach  e  ---cited  vomiting  and  convulsions.  The  25th  made  ten  days 
since  he  had  taken  any  fo  : .!  but  beer  and  a  little  water.  During  that  time  he  had  not 
slept  at  all.  On  the  25th  h-  complained  of  his  feet  being  dead,  and  of  being  distract- 
ed by  thirst ;  he  was  too  weak  to  crawl  to  the  spring,  and  yet  dreadfully  susceptible  of 
suffering.  The  29th  of  September  was  the  last  day  on  which  he  made  a  memorandum. 
No  dissection  of  his  body  was  made. — Journal  der  prafthch:  Heilkunde,  &c-  C.  FT.  Hufe- 
land,  Marz,  1819. 

A  criminal,  called  Viterbi,  determined  on  the  2d  of  December,  to  starve  himself  to 
death,  in  the  prison  of  Bastia,  where  he  was  confined.  During  the  first  three  days  of 
the  attempt,  he  felt  himself  progressively  tormented  by  hunger.  He  manifested  no  de- 
bility during  these  three  days,  nor  any  irregular  muscular  movement;  his  ideas  continued 
sound  and  he  wrote  with  his  usual  facility.  From  the  5th  to  the  6th  of  Dec.  the  much 
more  grievous  suffering  of  thirst  succeeded  insensibly  to  hunger-  Thirst  became  so 
acute  on  the  6th,  that  without  ever  deviating  from  his  resolution,  he  began  to  moisten 
his  lips  and  mouth  occasionally,  and  to  gargle  with  a  few  drops  of  water,  to  relieve  the 
burning  pain  in  his  throat;  but  he  let  nothing  pass  the  organs  <>f  deglutition,  being" 
desirous  not  to  assuage  the  most  insupportable  cravings,  but  to  mitigate  a  pain  which 
might  have  shaken  his  resolution.  On  the  6th  his  physical  powers  were  a  little  weak- 
ened ;  his  voice  was,  nevertheless,  still  sonorous,  pulsation  regular,  and  a  natural  heat 
equally  extended  over  his  whole  frame.  From  the  3d  to  the  6th  he  had  continued  to 
write ;  at  night  several  hours  of  tranquil  sleep  seemed  to  suspend  the  progress  of  his 
sufferings  :  no  change  was  remarkable  in  his  mental  faculties,  and  he  complained  of  no 
local  pain. 

Until  the  10th  the  thirst  had  become  more  and  more  insupportable :  Viterbi,  how- 
ever, merely  continued  to  gargle,  without  once  swallowing  a  single  drop  of  water ; 
but  in  the  course  of  the  10th,  overcome  by  excess  of  pain,  he  seized  the  jug  of  water, 
which  was  near  him,  and  drank  immoderately.  During  the  last  three  days,  debility  had 
:i;ade  sensible  progress,  his  voice  became  feeble,  pulsation  had  declined,  and  the  ex- 


22  APPENDIX. 

tremities  were  cold.     He,  however,  continued  to  write  :  and  sleep,  each  night,  afford- 
ed him  a  few  hours  ease. 

From  the  20th  to  the  12th  the  symptoms  made  a  slight  progress.  His  constancy  nevep 
yielded  an  instant :  he  dictated  his  journal,  and  afterwards  approved  and  signed  what 
had  been  written  agreeable  to  his  dictation.  During  the  night  of  the  12th  the  symptoms 
assumed  a  more  decided  character ;  debility  was  extreme,  pulsation  scarcely  sensible, 
his  voice  extraordinarily  feeble,  the  cold  had  extended  itself  all  over  his  body,  and  the 
pangs  of  thirst  were  more  acute  than  ever.  On  the  13th  the  unhappy  man,  thinking 
himself  at  the  point  of  death,  again  seized  the  jug  of  water  and  drank  twice,  after 
which  the  cold  became  more  severe  ;  and,  congratulating  himself  at  the  approach  of 
death,  he  stretched  himself  on  the  bed,  and  said  to  the  gendarmes  who  were  guarding 
him,  "Look  how  well  I  have  laid  myself  out."  At  the  expiration  of  a  quarter  of  an 
hour,  he  asked  for  some  brandy  ,  the  keeper  not  having  any,  he  called  for  some  wine, 
of  which'  he  took  four  spoonsfull.  When  he  had  swallowed  these  the  cold  suddenly 
ceased,  heat  returned,  and  he  enjoyed  a  sleep  of  four  hours. 

On  awaking  (on  the  morning  of  the  12th)  and  finding  his  powers  restored,  he  fell  into 
a  rage  with  the  keeper.  During  the  two  following  days,  he  resisted  his  inclination  to 
drink,  but  continued  to  gargle  occasionally  with  water/  During  the  nights  he  suffered 
a  little  from  exhaustion,  but  in  the  morning  found  himself  rather  relieved.  It  was  then 
he  composed  some  stanzas.  On  the  16th  in  the  morning  his  powers  were  nearly  annihi- 
lated, pulsation  could  hardly  be  felt,  and  his  voice  was  almost  wholly  inaudible ;  his  body 
was  benumbed  with  cold,  and  it  was  thought  that  he  was  upon  the  point  of  expiring.  At 
ten  oclock  he  began  to  feel  better,  pulsation  was  more  sensible,  his  voice  strengthened, 
and  heat  again  extended  over  his  frame  ;  and  in  this  state  he  continued  during  the  whol 
of  the  17th.  From  that  day  until  the  20th  he  only  became  more  inexorable  in  his  reso« 
lution  to  die. 

During  the  19th  the  pangs  of  hunger  and  thirst  appeared  more  grievous  than  ever : 
so  insufferable  indeed  were  they,  that,  for  the  first  time,  Viterbi  let  a  few  tears  escape 
him  ;  but  his  invincible  mind  instantly  spurned  the  human  tribute.  For  a  moment  he 
seemed  to  have  resumed  his  wonted  energy,  and  said  in  the  presence  of  his  guards,  "  I 
will  persist,  my  mind  shall  be  stronger  than  my  body,  my  strength  of  mind  does  not 
vary,  that  of  my  body  daily  becomes  weaker."  A  little  after  this  energetic  expression, 
which  showed  the  powerful  influence  of  his  moral  faculties  over  his  physical  necessities, 
an  icy  coldness  again  assailed  his  body,  the  shiverings  were  frequent  and  dreadful,  and 
his  loins  in  particular,  were  seized  with  a  stone  coldness,  which  extended  itself  down 
his  thighs. 

During  the  19th,  a  slight  pain  at  intervals  affected  his  heart,  and  for  the  first  time  he 
felt  a  ringing  sensation  in  his  ears.  At  noon,  on  this  day,  his  head  became  heavy ;  his 
sight,  however,  was  perfect,  and  he  conversed  almost  as  usual,  making  some  signs  with 
his  hands.  On  the  20th  he  declared  to  the  gaoler  and  physicans  that  he  would  not 
again  moisten  his  mouth,  and  feeling  the  approach  of  death, he  stretched  himself  on 
the  bed,  and  said,  "  I  am  prepared  to  leave  this  world."  Death  did  not  this  time  be- 
tray  his  hopes ;  on  the  21st  he  was  no  more.  Until  the  day  of  his  death  this  man  re- 
gularly kept  his  journal.  The  delivery  of  it  to  his  friends  was  refused.  (From  the  Cor- 
sican  Gazette.} 


Of  Digestion. 
Note  K. 

!•  Of  Digestion  in  the  Stomach.  M.  Lallemand  has  drawn  the  following  inferences 
from  his  observations  and  experiments  on  digestion  : 

"  1.  That,  if  it  be  true  that  alimentary  substances,  the  most  perfectly  animalizeo^ 
contain  the  most  nutritive  matter,  it  does  not  thence  follow  that  they  are  the  most  ra- 
pidly digested. 

«  2.  That,  on  the  contrary,  the  process  of  digestion  is  more  long  and  laborious,  as, 
in  a  given  volume,  the  aliment  contains  more  nutritive  matter,  and  vice  versa. 

"  3.  That  the  aliments  do  not  escape  from  the  stomach  in  the  order  in  which  they 
are  introduced,  but  that  it  is  not  those  which  are  first  altered  by  digestion  that  pass  the 
first :  it  is  those  on  the  contrary,  which,  containing  least  alimentary  matter,  are  most 
jreiractory  to  the  digestive  powers." 


OF  DIGESTIOK.  23 

Conformably  to  the  inferences  stated,  (in  note  H.  of  the  Appendix)  we  consider  that, 
whatever  may  be  the  order  in  which  the  ingesta  pass  the  pylorus  into  the  smaller  in- 
testines, the  digestive  process  in  the  stomach,  and,  indeed,  throughout  the  alimentary 
canal,  is  more  immediately  the  result  of  the  vital  influence  with  which  the  stomach  and 
intestines  are  endowed,  than  of  the  solvent  properties  of  the  gastric  juice.  We,  how- 
ever, by  no  means  would  be  understood  to  deny  that  these  properties  are  requisite  to 
the  process,  we  only  contend  that  they  are  subordinate  to  the  manifestation  of  vitality 
exerted  by  the  stomach,  and  that  the  vital  influence  of  this  viscus  is  chiefly  concerned 
an  its  performance.  The  digestive  process,  whether  that  part  of  it  which  is  performed 
in  the  stomach,  or  that  which  is  accomplished  by  the  small  intestines,  appears  to  be  es- 
sentially a  vital  process,  whether  we  view  it  in  man  or  in  any  of  the  lower  animals. 
Every  theory,  therefore,  which  excludes  its  immediate  operation,  must  be  defective. 
Conformably  to  this  view,  it  must  be  supposed  to  vary  in  activity, — as  indeed  we  ac- 
tually find  that  it  does,  according  to  the  state  of  the  vital  influence  with  which  the 
organs  concerned  in  its  accomplishment  are  originally  endowed,  and  according  to  the 
state  and  distribution  of  this  influence  with  which  the  organs  concerned  in  its  accom- 
plishment are  originally  endowed,  and  according  to  the  state  and  distribution  of  this 
this  influence  throughout  the  organs  and  textures  at  the  time  when  this  process 
is  going  forward.  We  do  not  deny  that  the  influence  which  we  impute  to  the 
stomach,  is  one  which  is  not  intimately  connected  with  the  gastric  juices ;  on  the 
contrary,  we  believe  that  they  are  the  medium  through  which  it  acts; — in  short, 
that,  owing  to  the  abundant  supply  of  nerves  which  this  viscus  receives,  chiefly  from 
the  ganglionic  system,  it  possesses  a  considerable  share  of  the  vital  influence  of  the 
body  ;  that  this  influence  is  chiefly  exerted  in  giving  rise  to  its  organic  motions,  and  in 
producing  its  specific  secretions,  and  that,  from  the  circumstance  of  so  large  a  propor- 
tion of  its  ganglial  nerves  being  distributed  on  its  arteries,  the  juices  which  they  se- 
crete or  exhale  are  imbued  with  an  emanation  or  some  certain  manifestation  of  this  in- 
fluence, which  is  the  principle  agent  in  the  digestive  process.  Hence  the  relation  be- 
tween the  states  of  this  influence,  and  the  quantity  and  quality  of  the  gastric  juices  must 
be  very  intimate;  and  it  seems  to  be  owing  to  this  intimacy,  that  the  primary  agent  has 
been  hitherto  overlooked  in  the  more  evident  and  grosser  materials  with  which  it  is  al- 
lied, and  by  means  of  which  it  operates.  The  varying  conditions  of  the  function  of  di- 
gestion in  health  and  in  disease,  and  the  close  connexion  between  it  and  every  manifes- 
tation of  the  body,  eminently  support  this  view  of  the  subject ;  and,  independently  of 
the  direct  evidence  fnrnished  by  the  very  interesting  experiments  of  Drs.  Wood  and 
Sillar,  of  Liverpool,  many  collateral  proofs  may  be  adduced  in  its  behalf. 

H.  Of  Vomiting.  W^hilst  we  attribute  the  digestive  process  chiefly  to  the  vital  influ- 
ence proceeding  from  the  ganglial  system,  we  do  not  overlook  the  fact  that  that  part  of 
this  system  supplying  the  stomach  is  acted  upon,  to  a  certain  extent,  through  the  me- 
dium of  nerves  communicating  with,  and  of  others  given  off  from,  the  cerebro-spinal 
system,  which  may  reasonably  be  supposed  to  perform  the  functions  belonging  to  their 
respective  sources. 

It  is  owing  to  this  provision,  when  the  stomach  is  irritated,  and  when  its  organic  con- 
tractility is  inordinately  excited,  that  its  sensibility  is  also  roused — the  influence  is  pro- 
pagated to  the  sensonmn,  and  contraction  of  the  abdominal  and  respiratory  muscles  is 
also  produced, — which  contracting  co-operates  with  that  of  the  stomach  itself,  in  giving 
rise  to  vomiting.  Magendie  has  inferred  from  his  experiments,  that  it  is  only  the  con- 
traction of  the  abdominal  muscles  and  diaphragm  which  produces  vomiting,  and  that 
the  stomach  has  no  share  in  the  act.  This  physiologist,  on  this,  as  on  other  occasions, 
has  not  taken  into  account  the  various  sources*  of  error  to  which  experiments  on  living 
animals  are  liable.  He  has  not  sufficiently  considered,  or  calculated  upon,  the  unna- 
tural positions  in  which  such  experiments  place  the  animals  experimented  upon,  and 
thus  derange  their  natural  operations.  Stricter  and  more  comprehensive  views  of  the 
subject  show  that,  whilst  former  physiologists  have  erred  in  attributing  the  act  of  vo- 
miting too  exclusively  to  a  sudden  contraction  of  the  stomach,  Magendie  and  his  disciples 
have  been  equally  to  blame  in  adopting  too  implicitly  the  more  tangible  phenomenon 
of  some  inconclusive  experiments.  The  steps  in  this'process  appear  to  be  the  follow- 
ing:— an  irritating  cause  rouses  the  organic  insensibility  of  the  stomach,  and  gives  rise 
to  a  considerable  contraction  of  its  muscular  coats.  This  exalted  state  of  its  organic 
sensibility  and  contractility  excites,  in  consequence  of  the  intimate  nervous  communica- 
tion between  the  stomach  on  the  one  hand,  and  the  diaphragm  and  abdominal  muscles 
on  the  other*,  the  action  of  the  latter,  which,  from  vicinity  of  situation,  perform  so  im- 

*  Through  the  medium  of  the  eighth  pair  of  nerves,  and  of  the  branches  of  the  gan- 
glia! system  which  joins  the  spinal  nerve?* 


24  APPENDIX. 

portant  a  share 4n  the  act.  Hence  it  follows,  that  neither  the  contraction  of  the  sto- 
mach alone,  nor  that  of  the  muscles  only,  can  be  sufficient  to  give  rise  to  the  act  of  vo- 
miting. It  would  seem  that  so  intimately  connected  are  inordinate  irritations  of  the 
stomach  with  the  action  of  the  diaphragm  and  abdominal  muscles,  owing  to  the  anato- 
mical relations  of  the  ganglial  system  with  the  eighth  pair  of  nerves,  and  with  those  of 
the  spinal  cord,  that  the  one  can  never  lake  place,  under  the  ordinary  state  of  the  sys- 
tem, without  being  followed  by  the  other,  and  giving  rise  to  the  act  under  considera- 
tion. The  nausea  which  precedes  vomiting,  is  merely  the  sensible  impression  made  by 
the  irritating  cause  on  the  nerves  of  the  stomach,  which  impression,  if  sufficiently  exalted, 
terminates  in  the  act  in  question.  When  this  step  of  the  process  is  about  to  take  place, 
the  diaphragm  is  the  first  to  contract  in  a  spasmodic  manner ;  indeed,  the  irritation  of 
the  stomach  having  excited  the  diaphragm,  the  former  is  struck  by  the  latter  against  the 
abdominal  muscles,  and  at  the  instant  when  the  diaphragm  relaxes,  the  abdominal  mus- 
cles re-act  and  impel  the  stomach  against  the  relaxed  and  ascending  diaphragm,  which, 
in  consequence  of  this  state,  readily  allows  the  contents  of  this  viscus  to  be  impelled,  by 
the  concussion  of  the  abdominal  muscles,  through  the  cardia  into  the  oesophagus.  That 
the  diaphragm  is  the  first  to  contract,  and  that  it  is  the  first  to  relax,  are  shown  by  at- 
tending to  the  steps  of  the  process,  and  by  the  fact  that  the  stomach  could  not  empty 
itself  through  the  cardia,  if  the  diaphragm  were  to  continue  in  a  state  of  contraction. 
It  will  therefore  appear  that  the  action  of  the  stomach  is  at  its  acme  when  the  abdominal 
muscles  re-act  and  consummate  the  process  ;  and  that,  whilst  the  diaphragm  commences 
the  operation,  the  abdominal  muscles  are  chiefly  efficient  in  perfecting  it.  It  must  be  kept 
in  recollection  that  both  do  not  contract  at  the  same  time.  The  violent  action  of  the  latter 
impels  the  stomach,  and,  indeed,  the  superior  viscera  of  the  abdomen,  so  forcibly  upon 
the  relaxed  diaphragm,  and  encroaches  so  much  upon  the  cavity  of  the  thorax,  the  whole 
respiratory  muscles  being  then  relaxed,  that  the  lungs  are  at  the  time  considerably  pres- 
sed upon?  and  this  pressure  is  farther  increased  by  the  ascent  of  the  contents  of  the 
stomach  through  the_cesophagus.  Hence  it  is  that  vomiting  always  promotes  the  dis- 
charge of  secretions  which  have  accumulated  in  the  bronchia^. 

HI.  Of  Human  Rumination,— -The  author  has  adverted  to  this  subject  in  the  text  in  a 
very  brief  manner.  As  this  affection  is  more  frequently  amongst  individuals  apparently 
enjoying  their  usual  health  than  is  generally  supposed  ?  and  as  many  who  habitually 
rumiftate  consider  it  to  be  only  a  step  of  the  digestive  process, — which  is  certainly  the 
truth  as  far  as  respects  themselves, — we  shall  enter  more  fully  into  the  subject,  as  it 
has  more  than  once  fallen  under  our  observation. 

Under  the  usual  circumstances,  rumination  commences  from  a  quarter  of  an  hour  to 
an  hour  and  a  half  after  a  meal.  Immediately  upon  the  commencement  of  this  act,  a 
slight  sensation  of  fullness  may  be  felt  at  the  cardia,  when  the  attention  is  particularly 
directed  to  it,  that  leads  to  a  deeper  inspiration  than  usual.  So  soon  as  the  act  of  in- 
spiration is  completed,  and  while  the  muscles  of  the  glottis  remain  fixed,  a  bolus  of  the 
unchanged  aliment  rises  rapidly  from  the  stomach,  with  the  first  effort  at  respiration, 
at  the  moment  when  the  diaphragm  has  just  relaxed,  and  the  re-action  of  the  abdomi- 
nal muscles  commenced.  But  expiration  does  not  take  place  until  the  alimentary  ball 
has  passed  completely  into  the  mouth,  as  the  glottis  remains  closed  until  then  :  upon 
this  having  taken  place,  expiration  is  immediately  effected  ;  and  so  rapidly  does  respi- 
ration succeed  to  the  regurgitation  of  the  alimentary  bolus,  that  the  latter  (unless  when 
the  attention  is  closely  applied  to  the  subject,)  appears  as  part  of  the  expiratory  act. 

The  ruminating  process  is  never  accompanied,  at  any  time,  with  the  smallest  degree 
of  nausea,  nor  any  pain  or  disagreeable  sensation.  The  returned  alimentary  bolus  is 
attended  with  no  unpleasant  flavour,  is  in  no  degree  acidulous,  and  is  equally  agreea- 
ble, and  is  masticated  with  additional  pleasure,  and  with  much  greater  deliberation 
than  when  first  taken. 

The  whole  of  the  aliments  taken  at  one  meal  is  not  returned  in  order  to  undergo  this 
process,  but  chiefly  the  part  that  has  been  insufficiently  masticated. 

The  more  fluid  portions  are  not  always  returned,  unless  along  with  the  more  solid  or 
imperfectly  masticated  parts.  When,  however,  the  stomach  is  distended  by  a  large 
meal,  the  fluid  contents  are  frequently  returned,  and  subjected  to  this  process 

This  affection  may  be  considered  as  being  passively  under  the  control  of  the  will ; 
and,  although  it  sometimes  takes  place  when  the  individual  is  nearly  unconscious  of 
the  process,  yet  it  never  occurs  when  ttie  mind  is  incapable  of  being  acted  on  hy  ex- 
ternal impressions  received  by  the  senses.  Thus,  if  at  any  time,  from  previous  fatigue, 
and  the  concentration  of  the  organic  nervous  energy  towards  the  digestive  organs, 
sleep  be  induced  immediately  after  a  full  meal,  this  affection  does  not  take  place  :  but 
flatulence,  acrid  eructations,  &c.  usually  supervene,  and  continue  for  some  time,  in 


OF  DIGESTION,  25 

consequence  of  the  vital  energy  and  gastric  juices  being  insufficient  to  the  production 
of  the  requisite  changes  on  the  ingesta  retained  in  a  state  of  imperfect  division. 

With  respect  to  the  nature  of  human  rumination  it  appears  evident  that  it  only  takes 
place  when  the  vital  energy  of  the  assimilating  organs  is  greatly  diminished  ;  conse- 
quently, when  the  activity  of  the  stomach,  both  as  it  relates  to  its'muscular  action  and 
secreting  functions,  is  equally  lessened ;  this  is  apparent  from  the  circumstance,  that 
aliments,  if  they  be  taken  even  in  very  moderate  quantity,  are  not  properly  digested  by 
ruminating  individuals  when  they  are  retained  without  having  been  re-submitted  to 
mastication.  Connected,  also,  with  debility  of  the  stomach,  an  increase  of  its  sensibi- 
lity, which  it  derives  from  the  distribution  of  the  eighth  pair  of  nerves,  seems  to*be 
present.  Both  these  states  of  this  organ  render  it  more  necessary  that  the  ingesta 
should  undergo  a  perfect  mastication  and  thorough  admixture  of  the  salivary  juices,  in 
order  to  suit  it  to  the  weakened  functions  of  the  stomach. 

Under  the  circumstances  of  deficient  vital  energy  of  the  stomach,  of  increased  sensi- 
bility, and  diminished  secretion,  a  small  portion  only  of  food  can  be  digested  ;  yet  it  is, 
nevertheless,  generally  taken  in  considerable  quantity  by  ruminating*  individuals.  In 
this  case,  that  portion  of  it  most  favourable  to  the  admixture  having  combined  with  the 
gastric  juices,  and  being,  by  the  natural  action  of  the  stomach,  conveyed  to  the  pylorus, 
the  undigested  portions  and  those  which  have  been  imperfectly  masticated,  must  either 
remain  at  the  cardiac  extremity,  or  be  propelled  there  by  the  usual  action  of  the  viscus, 
where  they  excite  its  organic  sensibility,  and,  in  consequence  of  intimate  nervous  con- 
nection, the  co-operation  of  the  muscles  of  respiration,  especially  of  the  diaphragm  and 
abdominal  muscles,  and  thus  give  rise  to  the  ruminating  process. 
fin  its  performance,  the  organic  contractility  of  the  stomach  can  do  no  more  than  by  au 
elective  process  (soon  to  be  explained)  place  the  aliments  about  to  be  returned  in  a 
situation,  in  respect  to  the  cardia,  favourable  to  the  excitation  of  the  organic  sensibility 
of  this  organ,  and  to  its  ready  regurgitation  and  propulsion  along  the  oesophagus.  As 
soon  as  the  demand  is  made  upon  the  sensibility  by  the  situation  of  the  alimentary 
bolus,  the  par  vagal  class  of  nerves  is  excited  to  action,  and  a  full  respiration  is  effected, 
as  has  been  described.  The  introduction  of  the  bolus  into  the  cardiac  extremity  of  the 
oesophagus,  may  be  considered  as  effected  by  the  ordinary  contractility  of  the  stomach  ; 
perhaps  sympathetically  heightened  at  the  moment  by  the  re-action  of  the  abdominal 
muscles ;  while,  at  the  same  time,  the  diaphragm  has  just  undergone  relaxation,  in 
which  the  cardia  may,  from  intimate  nervous  communication,  also  participate,  and  thus 
facilitate  the  ascent  of  the  alimentary  ball  in  the  cesophagus,  which  immediately  con- 
tracts behind  it  from  the  irritation  produced  by  its  passage,  and  the  bolus  is  thus  con- 
veyed to  the  mouth. 

That  relaxation  of  both  the  diaphragm  and  cardiac  extremity  of  the  cesophagus  ac- 
tually exists  at  the  moment,  although  the  glottis  still  remains  closed,  appears  confirm- 
ed, both  by  the  period  of  the  respiratory  act  at  which  this  process  is  produced,  and  by 
the  circumstance  that,  when  any  restraint  is  exercised  over  this  affection,  it  is  princi- 
pally by  means  of  exciting  the  diaphragm  to  a  frequent  and  continued  action,  when  the 
premonitory  sensation  is  felt  at  the  cardia. 

The  influence  of  the  will  appears  to  be  requisite,  since  the  process  is  interrupted 
during  sleep.  But  this  influence  is  only  passively  engaged  in  the  production  of  the  ru- 
minating act,  by  bringing  about  the  co-operation  of  the  respiratory  organs. 

The  elective  process  exercised  by  the  stomach  in  this  affection,  is  similar  to  that 
which  it  exerts  in  periods  of  health,  which  may  be  considered  as  relative  to  the  degree 
of  digestive  energy,  and  to  the  comparative  states  of  comminution  and  insalivation,  in 
v/hich  the  various  ingesta  may  enter  the  stomach. 

During  the  process  of  digestion,  contraction  takes  place  irregularly  and  under  various 
situations  in  this  organ,  according  as  different  portions  of  the  longitudinal  or  circular  fi- 
bres may  act ;  this  operates  in  producing  a  degree  of  arrangement  in  the  aliments  ; 
and,  as  the  gastric  juices  combine  with  the  more  soluble  portion  of  the  food,  especially 
that  situated  towards  the  mucous  surface  of  this  organ,  which,  when  duly  effected,  is 
conveyed  by  the  varying  organic  contractility  of  the  muscular  coat,  towards  the  pylo- 
rus ;  while  a  successive  and  concentric  stratum  comes  in  contact  with,  and,  if  in  a  per- 
meable state  from  its  previous  comminution  and  admixture  with  the  salivary  juices,  is 
soon  penetrated  by  the  secretions  of  this  organ  ;  and  even  the  central  mass  not  unfre- 
quently  is  obliged  to  yield  its  more  fluid  parts  to  the  exterior  layer,  when  there  is  a  de- 
ficiency of  fluids  in  the  alimentary  contents.  Hence  the  not  unusual  necessity  for  drink 
that  takes  place  as  digestion  proceeds..  In  the  course  of  this  process,  as  it  is  the  result 
of  the  healthy  functions  of  the  organ,  the  chyme  in  contact  with  its  mucous  surface  i.s 
conveyed  in  a  direction  from  the  cardia  to  the  pylorus.  But,  if  the  propagation  of  th- 
digested  contents  towmls  this  extremity  of  the  organ  proceed  faster  than  it  can  pa?3 

D 


through  into  thfe  duodenum,  thfe  accumulation  of  cuyme  that  consequently  fakes  plac£ 
in  that  direction,  tends  to  propel  the  less  soluble  portions  towards  the  cardia  ;  where, 
according  to  the  state  of  the  organ,  it  may  produce  cardialgia,  acrid  eructations,  or  even 
rumination. 

In  the  debilitated  state  of  the  stomach,  and  consequent  deficiency  of  the  secretions, 
digestion  can  be  perfectly  performed  only  when  the  aliments  are  presented  to  it  in 
small  quantity,  and  in  a  favourable  state  of  complete  comminution  and  intermixture 
with  the  salivary  juices,  If,  however,  in  this  condition  of  the  organ,  the  food  is  con- 
veyed  rapidly  into  it,  possessed  of  neither  of  these  requisites,  so  as  to  produce  sudden 
distension,  a  re-action  of  this  viscus  upon  its  contents  takes  place  ;  and,  as  the  imper- 
fectly masticated  food  constitutes  the  greater  portion  of  the  ingesta,  there  is  abundance 
present  to  be  returned  into  the  cardia  and  to  be  regurgitated,  while  there  is  a  defi~ 
ciency  of  aliment  in  a  fit  state  to  combine  with,  or  to  be  operated  upon,  by  the  gastric 
juices  ;  this  when  converted  into  chyme,  is  rapidly  conveyed  to  the  other  extremity  of 
the  organ,  by  the  re -action  of  the  muscular  coat,  arising  from  undue  distension  and  the 
stimulus  of  solid  contents.  Thus  a  double  effect  is  produced  by  the  healthy  organic 
contractility  of  this  viscus,  when  in  a  weakened  state,  and  yielding  a  diminished  quan- 
tity of  the  usual  fluids,  which  state,  indeed,  rnay  be  considered  as  constituting  this  pecu- 
liar affection, — namely,  the  part  of  the  aliment  which  is  dissolved  by  the  gastric  juices 
is  conveyed  toward  the  pylorus,  whilst  the  tonic  action  of  the  stomach  tending  to  di- 
minish its  capacity,  pushes  the  less  comminuted  and  indigestible  portions  of  food  into 
the  unresisting  cardia ;  whence  they  are  returned,  as  we  have  described,  in  order  to 
undergo  a  second  comminution  and  intermixture  with  the  salivary  juices  ;  after  which 
they  are  in  a  fit  state  to  be  conveyed  to  their  destination  along  the  mucous  surfaces, 
with  the  juices  of  which  they  combine,  and  thus  permit  a  central  portion  of  the  mass  to 
return  and  undergo  a  similar  process. 


Of  the  Influence  ofthefineumo-gastric  Nerves  in  Digestion* 
Note  L. 

The  experiments  of  Dr.  Phillip,  although  they  by  no  means  warrant  the  inferences 
•Which  he  deduced  from  them,  show  that  the  eighth  pair  of  nerves  conveys  the  influ- 
ence of  the  cerebro-spinal  system  to  the  stomach,  and  re-intbrces  and  stimulates  tha 
vital  energy  bestowed  on  it  by  the  ganglial  system.'  This  conclusion  is  farther  sup- 
ported  by  the  experiments  lately  performed  at  Paris  by  Breschet,  Edwards  and 
Vavasseur.  The  inferences,  which  these  physiologists  have  drawn  from  their  experi- 
ments, are — 

1st.  Simple  section  of  the  pneumo-gastric  nerves  in  the  region  of  the  neck,  without 
loss  of  substance,  and  without  separating  the  cut  extremities,  does  not  prevent  diges- 
tion from  taking  place,  but  merely  retards  it  in  an  evident  manner. 

2dty.  Section  of  these  nerves,  with  loss  of  substance,  diminishes  considerably,  and 
much  more  than  simple  section,  the  digestive  action  of  the  stomach,  but  it  does  not  ap- 
pear to  abolish  it  completely. 

3dly.  Section,  or  destruction  of  part  of  the  spinal  marrow,  or  removal  of  a  portion  of 
the  brain,  acts  in  the  same  manner  on  the  changes  which  the  food  undergoes  in  the  sto- 
mach. 

4thly.  Narcotics,  administered  so  as  to  produce  coma,  equally  dimmish  the  energy 
of  the  digestive  powers. 

Sthly.  It  results,  consequently,  that  every  thing  which  diminishes  the  amount  of  ner- 
vous influence,  transmitted  to  the  stomach,  weakens  the  digestive  action. 

6thly,  and  finally.  When  digestion  is  almost  completely  suspended  by  the  section, 
\vith  loss  of  substance,  of  the  pneumo-gastric  nerves,  the  digestive  action  of  the  sto- 
mach may  be  re-established,  and  the  food  contained  therein  be  converted  into  chyle,  by 
means  of  the  galvanic  influence,  with  almost  as  much  rapidity,  and  as  perfectly,  at  least 
in  appearance,  as  under  ordinary  circumstances.  {Archives  generates,  de  Medicine, 
.Aw*.  1823.) 

When  the  connexions  of  the  different  orders  of  nerves  which  supply  the  stomach  arc 
considered,  and  the  intimate  relation  consequently  subsisting  between  this  organ  and 
the  centres  to  which  these  nerves  respectively  belong,  it  cannot  for  a  moment  be 
doubted  that  the  interruption  of  the  channel,  through  which  this  connexion  takes 
place,  should  be  followed  by  a  deranged  stale  of  the  functions  depending  thereon.  Al- 


OF  I'NEUMO-GASTRIC  NE&VES  IN  DIGESTION.  $fi 

lowing  that  the  stomach  derives  its  chief  and  its  more  vital  influence  from  the  ganglial 
system,  and  an  additional  and  a  modified  influence  from  the  cerebro-spinal  system,  the 
latter  exciting-  or  otherwise  influencing  the  former,  and  granting  that  respiration  is  re- 
quisite to  the  energy  of  both,  it  surely  cannot  be  for  a  moment  doubted,  that  an 
interruption  either  of  the  one  or  the  other  should  occasion,  owing  both  to  the 
defect  of  a  requisite  influence  and  to  the  injury  done  to  the  system  generally  by 
the  experiment,  a  very  considerable  derangement  of  the  functions  of  this  organ.  We 
perceive  that  slighter  causes,  such  as  those  mentioned  at  p.  77  of  the  text,  will  produce 
a  much  greater  disorder  of  the  actions  of  the  stomach  than  the  formidable  operation  of 
division  of  the  eighth  pair  of  nerves — formidable  not  only  as  respects  its  effects  upon 
digestion,  but  as  regards  its  influence  on  the  function  of  respiration,  and  upon  the  body 
generally — can  it  therefore  be  a  matter  of  surprise,  that  destruction  of,  or  interruption 
to,  a  wonted  and  requisite  influence  should  be  followed  by  marked  effects  upon  the 
organ  which  such  influence  is  destined  to  actuate  ?  Because  the  influence  conveyed 
by  the  nerves  from  the  cerebro-spinal  sysem  affects  the  functions  of  the  stomach  or 
an  interruption  to  it  disorders  them,  can  it  therefore  be  logically  concluded  that  this 
viscus  derives  its  functions  from  that  source,  and  that  none  of  them  acknowledges  any 
other  origin  ?  Because  these  particular  nerves  are  ready  conductors  of  galvanism,  and 
because  galvanism  excites  the.  natural  actions  of  the  digestive  organs,  ought  it  therefore 
to  be  concluded,  that  the  natural  office  of  these  nerves  is  to  convey  and  distribute  this 
agent,  or  that  the  vital  influence  with  which  these  organs  are  endowed,  is  identically 
the  same  as  it  ?  We  think  that  no  one  can  be  justified  in  answering  these  questions  in 
the  affirmative,  by  the  evidence  which  these  experiments  afford.  From  a  careful  con-, 
tnderation  of  the  phenomena  which  they  furnished,  and  from  the  few  experiments 
\vhich  we  have  made  with  this  active  agent,  we  conclude, — 1st.-  That  the  functions  of 
the  stomach  depend  chiefly  upon  the  supply  of  ganglial  nerves,  which  its  vessels,  mus- 
cular fibres,  and  secreting  surface  receive.  2d.  That  the  pneumo-gastric  nerves  con- 
vey the  influence  of  the  cerebro-spinal  system  to  this  organ,  which  influence  re-inforces 
that  which  it  receives  from  the  ganglial  system,  or  proves  a  stimulus  to  it.  3d.  That 
this  latter  influence  is  more  requisite  to  the  perfect  performance  of  the  functions  of 
the  stomachj  the  older  the  animal  is,  and  the  higher  we  rise,  in  our  observations 
amongst  the  more  perfect  animals.  4th.  That  when  this  influence  is  interrupted,  in  a 
more  or  less  complete  manner,  in  its  course  to  the  stomach,  its  place  may  be,  in  some 
measure,  supplied  by  galvanism,  which  seems  to  excite  the  proper  or  vital  influence 
which  the  organ  receives  from  the  ganglial  system.  5th.  That  we  have  no  proof  of 
galvanism  acting  otherwise  in  the  process  than  as  a  stimulus  to  properties  already  pos- 
sessed by  the  organ  on  which  it  acts,  and  that  it  acts  in  those  experiments  through  a 
medium  to  which  the  organ  is  habituated,  and  in  a  great  measure  dependent  for  a  na- 
tural excitement.  6th.  That  although  galvanism  excites  the  functions  of  the  stomach, 
for  a  time,  we  have  no  evidence  of  its  continued  power  in  promoting  them,  during  a 
protracted  interruption  of  either  the  one  species  of  nervous  influence  or  the  other;  it 
even  appears  probable  that  the  continued  operation  of  this  agent,  although  like  other 
powerful  stimuli  it  at  first  actively  excites  the  natural  functions  of  the  part  on  which 
it  acts,  would,  nevertheless,  exhaust  them,  more  especially  if  they  were  not  supplied 
from  their  natural  sources.  7th.  That,  as  we  have  no  comparative  trials  of  the  effects 
of  other  powerful  stimuli,  under  similar  circumstances  to  those  in  which  galvanism  has 
been  employed,  conclusive  inferences  cannot  be  drawn  respecting  the  extent  of  influ- 
ence of  that  agent ;  at  least  none  that  can  oppugn  the  above  positions,  they  may,  and, 
very  probably,  they  will  confirm  them,  and  show  that  the  activity  of  galvanism  in  exci- 
ting the  animal  operations,  merely  results  from  the  properties  of  this  agent  enabling  it 
to  act,  through  channels  which  convey  a  natural  and  a  requisite  influence,  in  a  more 
energetic  manner  than  other  excitants  which  we  can  employ  in  our  experiments.  Rea* 
soning,  indeed,  from  what  we  already  know  of  the  properties  of  galvanism,  and  from 
its  operations  upon  inorganized  matter,  we  should  be  led  to  expect  more  energetic  ef- 
fects from  it  upon  the  animal  system,  than  from  any  other  agent  which  we  have  under 
our  control. 


28  APPENDIX. 

Of  the  Intimate  Structure  and  Functions  of  the  Liver. 

Note  M. 
The  very  minute  researches  of  Dr.  J.  M.  -Mappes,  of  Frankfort  on  the  Maine,  on  the 


rnately  it  will  itself  pass  out  of  those  vessels.  If  the  liver  be  now  examined,  either  by 
dissecting  of  the  peritoneum,  or  cutting  or  tearing  the  liver,  two  structures  will  be  ob- 
served ;  the  one  granulated,  forming  convolutions,  now  resembling  those  of  the  intes- 
tines, and  now  branching  in  other  forms  ;  flattened  and  yet  rounded,  dense  and  of  a  yel- 
low colour,  and  about  a  quarter  of  aline  in  diameter — the  other  a  cellulo-vascular  struc- 
ture,  of  a  brown  colour,  which  fills  up  the  rounded  spaces  or  oblong  fissures,  of  from  a 
quarter  to  a  half  a  line  in  diameter,  which  separate  the  convolutions  from  each  other. 
These  strictures  are  well  shown,  if  water,  in  which  cinnabar  has  been  diffused,  be  thrown 
into  the  hepatic  veins ;  for  the  cinnibar  is  precipitated  on  the  sides  of  the  vessel,  and 
the  water  passes  by  the  vena  portae.  Between  the  convolutions  are  found  triangular  and 
somewhat  broken  openings,  which  communicate  with  each  other  by  little  chinks. 
Some  of  these  contain  twigs  of  the  hepatic  vein  ;  in  the  others,  and  especially  where 
the  chinks  are  traced  to  a  great  depth,  and  where  the  vessels  form  larger  trunks,  three 
vessels  are  seen  together,  a  large  one  belonging  to  the  hepatic  vein,  and  two  others,  of 
a  smaller  diameter,  belonging  to  the  artery  and  the  hepatic  duct. 

"  If  the  hepatic  vein  be  excepted,  the  other  vessels  form  branches  like  a  tree,  as  in 
the  rest  of  the  body.  The  artery,  however,  gives  the  most  branches  ;  apparently,  be- 
cause they  surround,  like  a  capillary  net-work,  the  parietes  of  the  vena  ports,  to  which 
purpose  they  seem  to  be  particularly  destined :  although  some  brandies  penetrate  to 
the  surface  of  the  liver,  and  are  distributed  on  the  peritoneum — but  without  forming  a 
net-work,  as  in  the  former  case.  The  ramifications  of  the  hepatic  artery  and  the  hepatic 
duct  are  always  strictly  united  together ;  and,  in  accompanying  the  larger  branches  of 
the  vena  portae,  they  do  not  intertwine  at  the  two  opposite  sides  of  the  latter  vessel. 

"  The  large  branches  of  the  hepatic  duct  divide  at  an  acute  angle  ;  but  the  ramifica- 
tions divide  at  right,  or  even  obtuse  angles.  It  is  these  latter  short  and  loose  twigs  which 
form  the  parallel  ranges  of  holes,  which  are  seen  by  cutting1  the  liver  in  the  direction 
of  a  branch.  These  holes  are  the  orifices  of  vessel,  as  is  seen  by  injection  or  by  dis- 
secting the  twigs :  they  cannot,  therefore,  be  confounded  with  the  little  dimples  which 
are  seen  on  the  internal  parietes  of  the  largest  hepatic  trunks.  All  the  ramifications  of 
the  hepatic  trunk,  indeed,  when  cut,  present  a  gaping,  firm  opening,  like  an  artery ; 
whilst  the  cut  orifice  of  the  vena  portse,  which  accompany  them,  are  always  in  a  col- 
lapsed state. 

«<  The  duct  ramifies  something  like  the  vein.  The  short  and  thick  trunks  divide  into 
branches,  and  form  a  crowd  of  smaller  and  looser  twigs,  which  embrace  the  grains  of 
the  granular  substance  above  described,  but  apparently  without  penetrating  the  sub- 
stance of  them.  Hence,  these  grains  are  somewhat  separated  from  each  other,  and  they 
in  some  degree  compress  the  cellulo-vascular  substance,  without,  however,  giving  any 
of  their  colour  to  the  latter,  which  is  only  traversed  by  some  injected  vessels. 

"  The  parietes  of  the  artery,  the  vena  ports,  and  the  hepatic  duct,  do  not  adhere  to 
the  substance  of  the  liver  ;  but  are  separated  from  it,  as  may  be  seen  by  the  microscope, 
partly  by  a  uniform  gelatinous,  matter,  and  partly  by  an  extension  of  the  cellular  mem- 
brane, which  composes  the  capsule  of  Glisson.  The  hepatic  vein,  on  the  contrary,  ad- 
heres intimately  to  the  granulated  substance  ;  it  also  follows  without  variation,  the  lat- 
ter in  its  distribution,  and  the  smallest  branches  penetrate  between  its  granulations. 
These  facts  prove  the  intimate  relation  which  exists  be  ween  (he  vein  and  the  granular 
substance  :  whilst  the  artery  and  vena  portse  ramify  together  in  the  cellulo-vascular  sub- 
stance, and  on  the  surface  of  the  principal  circumvolutions  of  the  granulated  substance; 
atid  the  hepatic  duct,  the  twigs  of  whicli  are  averted  from  each  other,  seems  to  hold  a 
relation  with  both  orders  of  vessels. 

"  If  a  single  hepatic  vessel  be  injected,  the  injection  will  only  pass  to  the  part  to 
M'hich  that  braivch  is  distributed  ;  on  the  contrary,  water  passes  rapidly  and  easily  from 


*  Journal  Complernentairc  du  Dictionnaire  des  Sciences  Medicales*  No,  46  Mai,  1822. 


INTIMATE  STRUCTURE  AND  FUNCTIONS  OV  THE  LIVER.         29 

the  vena  porta  to  the  hepatic  vein,  and  rice  versa.  Wax,  however,  rarely  passes,  and 
the  hepatic  duct  is  never  filled  either  from  the  vena  portee  or -hepatic  vein." 

From  these  facts  M.  Mappes  is  led  to  consider  the  granular  substance  to  be  the  se- 
creting part  of  the  liver,  around  which  the  vessels  are  grouped  as  the  conducting1  and 
preparatory  apparatus.  The  more  intimate  connexion  which  it  holds  with  the  radicles 
of  the  hepatic  vein  has  induced  him  to  presume  that  the  bile  is  more  probably  separated 
by  it,  from  the  blood  which  had  actually  arrived  within  these  radicles,  than  from  that 
which  circulates  in  the  extreme  ramifications  of  the  vena  portae.  This  particular  sub- 
stance  appears  also  to  M.  M.  to  form  the  basis  of  all  the  glands,  and  to  be  of  a  peculiar 
nature,  modified  according  to  the  functions  which  nature  has  imposed  on  it.  He  fur- 
ther supposes,  that  in  all  glandular  structures  there  exists  an  intermediate  substance, 
between  the  extreme  ramifications  of  both  orders  of  vessels,  which  holds  a  more  inti- 
mate relation  with  the  changes  induced  in  the  blood,  than  the  other  parts  through  which 
it  circulates.  This  substance  he  conceires  to  be  of  a  mucous  character,  and  to  form  the 
basis  of  the  granular  part  of  the  liver  and  other  glands,  in  which  the  vessels  terminate 
and  commence,  and  which,  he  thinks,  is  entirely  appropriated  to  the  particular  function 
and  destination  which  the  gland  is  intended  to  fulfil.  In  proof  of  this  he  quotes  Dcellinger. 
who  has  adopted  a  similar  opinion.  M.  Mappes,  in  an  analysis  which  he  offers  of  Ey- 
senhardt's  investigations  respecting  the  anatomy  of  the  kidney,  concludes  that  the  inti- 
mate structure  of  this  organ  and  the  liver  is  in  many  respects"  similar. 

Although  it  is  generally  agreed  amongst  physiologists  that  the  secretion  of  the  bile 
takes  place  in  the  granular  structure  of  this  visc'us,  it  is  by  no  means  so  generally  allowed 
that  the  secretion  is  furnished  by  the  blood  of  the  vena  portse.  Bichat  contended  that 
the  bile  is  secreted  from  the  hepatic  artery,  and  adduced  numerous  analogies  in  support 
of  the  opinion.  More  recently  M.  Magendie  has  considered  it  to  be  formed,  at  the 
same  time,  from  the  blood  of  both  the  portal  and  arterial  systems. 

It  seems  to  us  most  probable,  reasoning  from  the  facts  ascertained  respecting  absorp- 
tion, that  the  blood  which  circulates  in  the  vena  portae,  being  that  which  is  possessed 
of  the  venous  characters  in  the  highest  degree,  and  which,  moreover,  has  a  considera- 
ble portion  of  new  materials — the  products  of  digestion  and  absorption — poured  into  it 
before  it  reaches  the  liver,  undergoes  there  those  changes  which  are  necesssary  to  a 
perfect  assimilation  of  these  materials,  and  to  the  future  offices  which  the  blood  itself 
has  to  perform  in  the  animal  economy  ;  and  that,  in  the  course  of,  or  in  addition  to, 
these  changes,  the  blood  of  the  vena  portce  has  certain  of  its  elements  eliminated  from 
it,  the  elimination  of  which  is  requisite  not  only  to  the  accomplishment  of  these  chan- 
ges, but  also  to  the  production  of  a  secretion  which  perform  certain  offices  in  the  pro- 
cess of  digestion.  This  view  of  the  subject  is  supported  by  the  facts, — 1st,  that  those 
elements,  of  which  the  bile  is  composed,  abound  the  most  in  the  blood  of  the  vena  por- 
tx,  and  that,  if  they  were  to  remain  in  the  blood  circulating  throughout  the  body,  con- 
sequences subversive  of  its  healthy  existence  would  rapidly  supervene;--2d,that  the  por- 
tal ramifications  are  plentifully  supplied  with  the  ganglial  nerves,  which  we  have  shovvu 
to  be  the  source  whence  the  blood-vessels  derive  their  vitality  and  functions,  and  the 
origin  of  those  changes  which  the  fluid  circulating  in  them  experiences ; — and  3d,  that 
the  divisions  themselves  of  the  vena  portse,  receive  a  much  greater  supply  of  arterial 
capillaries  from  the  arteria  hepatica  than  is  observed  with  respect  to  any  other  vein  in 
the  body. 

From  anatomical  investigation,  therefore, — from  numerous  experiments  bearing1  in- 
directly on  the  subject,  and  from  pathological  observation,  we  infer,  that  the  blood 
which  returns  from  the  digestive  tube,  from  the  spleen,  &c.  [having  been  shown  to 
contain  a  considerable  portion  of  absorbed  materials,  some  of  them  of  a  more  or  less 
heterogeneous  description,  others  of  them  more  or  less  animalized  ;  and,  moreover,  that 
certain  of  the  elements  or  constituents  of  the  blood,  requiring  to  be  eliminated  from 
the  system,  are  there  in  an  increased  and  hurtful  quantity,  if  they  were  allowed  to  re- 
main in  it,  undergoes  in  the  liver  most  important  changes ;  that  these  changes  are  of 
two  kinds,  the  one  referring  to  the  assimilation  of  the  less  animalized  materials  which 
the  blood  may  contain,  the  other  to  the  elimination  of  the  heterogeneous,  hurtful,  or 
effete  elements  which  may  circulate*  in  it ;  that  these  are  produced  through  the  me- 
dium of  the  vessels  and  granular  structure  of  the  liver,  by  the  vital  influence  with  which 
both  are  endowed  from  the  ganglial  nerves  supplying  them  ;  that  these  changes  are  per- 
fect or  defective,  in  proportion  as  that  influence  is  perfect  or  defective,  provided  that 
the  structure  of  the  parts- — the  instruments  of  this  influence,  be  not  deranged  ;  and  that 
as  the  vital  functions  of  the  organ,  depending  upon  the  sources  pointed  out,  may  vary 
very  greatly;  and,  as  the  structure  of  one  or  more  of  the  parts  constituting  the  organ 
may  consequently  become  deranged,  the  operations  of  the  liver  may  be  thus  disorded 
:u  a  simnle  o?  more  or  less  complex  manner. 


30  APPENDIX. 

Oftte  Uses  of  the  JBile.  Various  opinions  have  been  entertained  by  physiologists  re- 
specting the  purposes  of  the  bile.  "  Some  have  supposed  that  the  secretion  of  bile  is 
merely  excrementitious  ;  others  that  the  bile  is  intended  to  stimulate  the  intestine,  and 
to  produce  a  ready  evacuation  of  the  faeces ;  and  another  opinion  has  been,  that  the 
bile  is  poured  out  into  the  duodenum,  that  it  may  be  blended  with  the  chyme,  and  by 
producing  chemical  changes  in  it,  convert  it  into  chyle.  The  situation  of  the  liver,  con- 
nected as  it  is  in  every  instance  with  the  upper  part  of  the  alimentary  canal,  is  unfa- 
vourable to  the  first  of  these  hypotheses  ;  but  the  last  is  rendered  very  probable  by  the 
circumstance  of  chylincation  taking  place  just  at  the  part  where  the  bile  flows  into  the 
bowel." 

In  order  to  arrive  at  some  satisfactory  conclusion  on  these  points,  Mr.  Brodie  applied 
a  ligature  round  the  choledic  duct  of  an  animal,  so  as  completely  to  prevent  the  bile 
entering  the  intestine,  and  then  noted  the  effects  produced  on  the  digestion  of  the  food 
which  the  animal  had  swallowed,  either  immediately  before  or  immediately  after  the 
operation.  The  experiment  was  repeated  several  times,  and  the  results  were  uniform. 
Before  he  describes  these  results,  he  remarks,  that  the  "  application  of  a  ligature  round 
the  choledic  duct  is  easily  accomplished,  and  with  very  little  suffering  to  the  animal ; 
so  that  any  derangement  in  the  functions  of  the  viscera,  which  follows,  cannot  reasona- 
bly be  attributed  to  the  mere  operation.  The  division  of  the  stomachic  ropes,  or  ter- 
minations of  the  eighth  pair  of  nerves  on  the  cardia  of  the  stomach,  and  the  ligature  of 
the  whole  extremity  of  ihe  pancreas,  are  operations  of  much  greater  difficulty  :  yet  it 
has  been  ascertained  that  neither  of  these  at  all  interfere  with  the  conversion  of  the 
food  into  chyme,  or  that  of  the  chyme  into  chyle-" 

"  When  an  animal,"  Mr.  Brodie  proceeds  to  state,  «  swallows  solid  food,  the  first 
change  which  it  undergoes  is  that  of  solution  in  the  stomach.  In  this  state  of  solution 
it  is  denominated  chyme.  The  appearance  of  the  chyme  varies  according  to  the  nature 
of  the  food.  For  example,  in  the  stomach  of  a  cat  the  lean  or  muscular  part  of  animal 
food  is  converted  into  a  brown  fluid,  of  the  consistence  of  thin  cream ;  while  milk  is 
first  separated  into  its  two  constituent  parts  of  coagulum  and  whey,  the  former  of 
which  is  afterwards  redissolved,  and  the  whole  converted  into  a  fluid  substance,  with 
vexy  minute  portions  of  coagulum  floating  in  it.  Under  the  ordinary  circumstances, 
the  chyme,  as  soon  as  it  has  entered  the  duodenum,  assumes  the  character  of  chyle. 
The  latter  is  seen  mixed  with  excrementitious  matter  in  the  intestine  ;  and  in  its  pure 
state  ascending  the  lacteal  vessels.  Nothing  like  chyle  is  ever  found  in  the  stomach  j 
and  Dr.  Prout,  whose  attention  has  been  much  directed  to  the  chemical  examination  of 
these  fluids,  has  ascertained,  that  albumen,  which  is  the  principal  component  part  of 
chyle,  is  never  to  be  discovered  higher  than  the  pylorus.  Now,  in  my  experiments, 
which  were  made  chiefly  on  young  cats,  where  a  ligature  had  been-  applied  so  as  to  ob- 
struct the  choledic  duct,  the'first  of  these  processes,  namely,  the  production  of  chyme 
in  the  stomach,  took  place  as  usual ;  but  the  second,  namely,  the  conversion  of  the 
chyme  into  chyle  was  invariably  and  completely  interrupted.  Not  the  smallest  trace 
of  chyle  was  perceptible  either  in  the  intestines  or  in  the  lacteals.  The  former  contained 
a  semi-fluid  substance,  resembling  the  chyme  found  in  the  stomach  with  this  difference, 
however,  that  it  became  of  a  thicker  consistence  in  proportion  as  it  was  at  a  greater  dis- 
tance from  the  stomach  ;  and  that,  as  it  approaches  the  termination  of  the  ileum  in  the 
csecum,  the  fluid  part  of  it  had  altogether  disappeared,  and  there  remained  only  a  solid 
substance,  differing  in  appearances  from  ordinary  fxces.  The  lacteals  contained  a  trans- 
parent fluid,  which  I  suppose  to  have  consisted  partly  of  lymph,  partly  of  the  more  fluid 
part  of  the  chyme,  which  had  become  absorbed. 

"  I  conceive  that  these  experiments  are  sufficient  to  prove  that  the  office  of  the  bile 
is  to  change  the  nutritious  part  of  the  chyme  into  chyle,  and  to  separate  from  it 
the  excrementitious  matter.  An  observation  will  here  occur  to  the  physiologist.  If 
the  bile  be  of  so  much  importance  in  the  animal  economy,  how  is  it  that  persons  occa- 
sionally live  for  a  considerable  time,  in  whom  the  flow  of  bile  into  the  duodenum  is  in- 
terrupted ?  On  this  point  it  may  be  remarked,  1st,  That  it  seldom  happens  that  the 
obstruction  of  the  choledic  duct  from  disease  is  so  complete  as  to  prevent  the  pas- 
sage of  the  bile  altogether;  and  the  circumstances  of  the  evacuations  being  of  a  white 
colour  may  prove  the  deficiency,  but  does  not  prove  the  total  absence  of  bile.  2ndly, 
That  in  the  very  few  authenticated  cases  which  have  occurred,  of  total  obliteration  of 
the  choledic  duct  in  the  human  subject,  there  has  been,  I  believe,  always  extreme 
emaciation,  showing  that  the  function  of  nutrition  was  not  properly  performed.  3dly, 
That  the  fact  of  individuals  having  occasionally  lived  for  a  few  weeks  or  months  under 
these  circumstances  only  proves  that  nutrition  may  take  place  to  some  extent  without 
chyle  being  formed.  In  my  experiments  I  found  that  the  more  fluid  parts  of  the 
chyme  had  been  absorbed,  and  probably  this  would  have  been  sufficient  to  maintain 
life  during  a  limited  period  of  time."—  (Journal  of  Science  and  the  *%rts,  No-  28.) 


OF  THIS  STRUCTURE  AKD  FUNCTIONS  OP  THE  SPLEEN.    31 

Dr.  Stearns  of  New  York,  is  of  opinion  that  the  gall-bladder  is  not  passive  in  the 
reception  of  the  bile,  and  that  it  is  not  a  mere  receptacle  for  this  fluid.  He  supposes 
that  the  cystic  duct  acts  as  an  absorbent,  selecting1  from  the  bile  in  the  hepatic  duct,  ita 
more  active  ingredients,  which  are  carried  into  the  gall-bla  ider,  where  they  remain 
until  "some  peculiar  irritation"  of  the  mouth  of  the  common  duct,  by  the  passing 
chyme  or  by  some  other  stimulating  cause,  solicits  its  discharge,  in  a  gradual  manner, 
for  the  purpose  of  purging  the  intestines.  In  support  of  this  opinion  he  refers  to  the 
experiments  of  Dr.  Douglass,  of  the  same  city,  who  found  that  the  bile  which  passed 
clirectJy  from  the  hepatic  duct  into  the  intestines  was  bland  and  harmless,  and  was 
mixed  with  the  chyme,  and  thus  seemed  to  aid,  as  shown  by  the  very  conclusive  ex- 
periments of  Mr.  Brodie,  in  the  formation  of  the  chyle,  and  of  the  new  materials  for 
the  nourishment  of  the  body ;  whilst  the  bile  found  in  the  gall-bladder  was  always  bit- 
ter, pungent,  and  viscid. 

These  properties,  however,  of  the  cystic  bile  may  supervene  without  any  election 
being  exerted  by  the  cystic  duct  in  the  process ;  for  if  we  suppose,  what  is  most  pro- 
bable, that  during  the  empty  state  of  the  duodenum  the  bile  flows  into  the  gall-bladder, 
where  its  more  bland  and  fluid  portions  are  removed  by  the  numerous  absorbent  ves- 
sels with  which  the  gall-bladder  and  its  ducts  &re  provided,  and  where,  during  its 
retention,  its  elements  combine  in  such  a  manner  as  to  modify  the  characters  of  the  se- 
cretion, and  to  render  them  very  different  from  those  which  it  evinced  immediately 
after  its  formation,  we  have  a  sufficient  reason  for  the  more  pungent  qualities,  of  cys- 
tic bile.  It  seems  by  no  means  unlikely,  therefore,  that  the  change  takes  place  in  the 
bile  itself  within  the  gall-bladder,  and  that  it  is  promoted  by  the  temperatui-e  and  vital 
influence  of  the  system. 

With  respect  to  Dr.  Stearns's  opinion,  that  the  gradual  flow  of  the  cystic  bile  into 
the  intestines  serves  the  purpose  of  a  gentle  purge  or  stimulus  to  their  functions,  it  ia 
by  no  means  new ;  but  we  have  no  more  proof  that  it  acts  the  part  of  a  purge,  than 
that  it  performs  the  office  of  an  astringent.  How  is  it,  if  this  opinion  be  correct,  that 
diarrhoea,  or  a  lax  state  of  the  bowels,  is  so  often  observed  during  the  interruptions  of 
the  biliary  secretion,  and  especially  of  the  cystic  bile  ? 

After  the  full  detail  of  the  results  of  Mr.  Brodie's  con  elusive  experiments  we  need 
not.state  at  greater  length  modern  views  upon  the  subject.  In  the  note  upon  the  function 
of  respiration,  we  will  briefly  notice  some  peculiarities  connected  with  the  functions  of 
the  liver  and  conditions  of  the  bile. 


Of  the  Structure  and  Functions  of  the  Spleen* 
Note  N. 

Although  considerable  attention  has  been  paid  to  the  physiology  of  the  spleen,  yet 
its  functions  are  but  imperfectly  understood.  They  have,  indeed,  been  variously  ex- 
plained by  philosophers,  but  all  have  erred,  chiefly  in  endeavouring  to  assign  to  it  one 
definite  function  only,  which  they  consider  it  to  perform  under  all  the  circumstances 
which  influence  the  body.  Thus,  Malpighi,  Haller,  Blumenbach,  Richerand  and 
Fodere,  imagine  this  organ  to  be  subservient  in  its  functions  to  those  of  the  liver. 
Hewson  believed  it  to  be  destined  to  the  elaboration  of  the  globules  of  the 
blood.  Tiedemann,  and  Gmelin  are  of  opinion,  that  it  is  intimately  Connected  with 
the  absorbent  system,  and  that  it  assists  the  process  of  sanguifaction.  Haighton  and 
Moreschi,  consider  that  it  is  subordinate  to  the  stomach  in  the  process  of  digestion; 
and  many  pathologists  believe  that  it  permits,  in  consequence  of  its  peculiar  texture, 
accumulations  of  blood  to  take  place  within  it  during  certain  stages  of  disease,  and 
that  it  thus  prevents  more  vital  organs  from  suffering  injury  to  which  they  would  other- 
wise be  liable.  To  us,  however,  it  appears  more  rational,  and  certainly  more  consis- 
tent with  the  operations  which  characterize  the  economy  of  the  more  perfect  animals, 
to  view  the  functions  of  this  organ  as  intimately  relating  to  those  which  the  absorbent, 
circulating,  and  secreting  systems  perform,  and  as  including  several  of  the  operations, 
just  specified,  to  a  greater  or  less  extent,  according  to  the  influence  to  which  the  body 
is  subjected. 

In  order  to  learn  the  nature  of  the  offices  which  the  spleen  performs  in  the  animal 
economy,  it  ought  to  be  our  first  object  to  ascertain  correctly  its  structure  ;  that  is, 
however,  a  matter  of  gveat  difficulty.  The  attention  of  anatomists  has  lately  been  par- 
ticularly directed  to  the  subject,  and  Home,  Heusinger,  and  Hopfengaertner,  have  been 


3&  APPENDIX, 

assiduous  in  that  investigation,  without,  however,  determining  the  much  disputed  point, 
whether  or  no  this  viscus  possesses  a  proper  or  glandular  structure,  or  is  it  simply  a 
minute  and  infinite  interlacement  of  arteries,  veins,  and  lymphatics.  Sir  Everard 
Home  concludes  from  his  researches,  that,  "  it  consists  of  blood-vessels,  between  which 
there^isno  cellular  membrane,  and  the  interstices  are  filled  with  serum,  and  the  colour- 
ing matter  of  the  blood  from  the  lateral  orifices  in  the  veins,  when  these  vessels  are  in 
a  distended  state  ;  which  serum  is  afterwards  removed  by  the  numberless  absorbents 
belonging-  to  the  organ,  and  carried  into  the  theoracic  duct  by  a  very  large  absorbent." 
Sir  Everar;'  considers  "  the  spleen,  from  this  mechanism,  to  be  a  reservoir  for  the  super- 
abundant serum,  lymph  globules,  soluble  mucus  and  colouring  matter,  carried  into  the 
circulation  immediately  after  the  process  of  digestion  is  completed. 

M.  Beclard,  (additions  to  the  anat.  genewle  of  Bichat,)  has  given  an  opinion  respect- 
ing  the  structure  of  this  viscus,  which  appears  to  be  the  most  correct  yet  offered.  He 
considers  that  it  belongs  to  the  class  of  erectile  tissues,  and  that  its  structure  results 
from  a  peculiar  arrangement  of  arteries  and  veins  similar  to  that  which  is  found  in  the 
penis,  the  clitoris,  and  female  nipple.  M.  B.  thinks,  that  the  spleen  very  nearly  resem- 
bles the  cavernous  body,  of  the  penis,  both  in  structure  and  in  its  phenomena ;  and  he 
considers  it  not  only  to  consist  of  erectile  tissue,  but  to  be  also  the  seat  of  a  species  of 
erection  more  or  less  similar  to  that  of  the  cavernous  body.  This  viscus,  he  argues,  pre- 
sents an  actual  motion  of  expansion  and  contraction,  and  he  adduces  the  three  following 
circumstances  under  which  this  takes  place.  1st,  In  experiments  ;  when  the  course  of 
blood  in  the  splenic  vein  is  arrested  in  living  animals,  the  spleen  swells,  but  returns  to 
its  former  dimensions  as  soon  as  the  circulation  through  the  vein  is  restored.  2d,  In 
diseases  ;  the  paroxysms  of  intermittents  are  accompanied  with  an  obvious  enlargement 
of  this  viscus,  which  subsides  as  soon  as  the  paroxysm  is  over.  3d,  A  similar  phenom- 
enon takes  place  during  digestion.  The  lateral  openings  of  the  veins,  noticed  by  Sir 
Everard  Home,  seem  to  confirm  the  views  of  M.  Beclard  respecting  the  dilation  and 
frequent  inosculations  of  the  venous  radicles  in  this  viscus,  which  are  common  to  it  and 
the  other  erectile  tissues.  (See  the  note  in  the  appendix  on  the  organs  of  Generation.) 

With  respect  to  the  functions  of  the  spleen  we  will  only  adduce  those  views  which 
possess  claims  to  a  favourable  notice. 

C.  H.  Schmidt,  (Comment.  dePathol  Lienis.)  considers  that  its  vasa  brcvia  contribute 
to  nourish  and  strengthen  the  stomach;  and  that,  as  the  blood  of  dogs  deprived  of  the 
spleen,  is  found  to  run  speedily  to  putrefaction,  it  is  concerned  in,  the  preparation  and 
assimilation  of  the  elements  of  the  blood,  and  that  it  performs  an  office  to  the  liver 
analogous  to  that  which  the  lungs  fulfil  with  respect  to  the  heart. 

Professors  Tiedemann  and  Gmelin  (Versuche  uber  die  Verriclitnng  der  MHz,  &c.*\  con- 
clude, from  their  investigations  on  this  subject,  1st,  That  the  spleen  is  an  organ  closely 
connected  with  the  lymphatic  system.  This  is  shown  by  its  being  restricted  to  those 
animals  which  possess  a  separate  absorbent  system,  by  the  number  of  its  lymphatic 
vessels,  and  by  the  circumstance  of  the  spleen  of  the  turtle  being  similar  to  a  mesen- 
teric  gland.  2nd,  That  a  coagulating  fluid  is  secreted  in  it  from  the  arterial  blood,  is 
taken  up  by  the  absorbents,  and  carried  into  the  thoracic  duct.  This  fluid  or  lymph, 
they  remark,  was  seen  not  only  by  them,  but  by  Hewson  ;  and  they  conclude,  that  the 
formation  of  it  is  the  only  means  by  whic"i  it  is  possible  to  account  for  the  use  of  the 
great  quantity  of  arterial  blood  which  flows  into  the  spleen.  In  answer  to  the  ques- 
tion,—by  what  means  this  coagulable  lymph  passes  into  the  absorbents  ?  they  reply, — 
either  there  are,  in  the  substance  of  this  organ,  particular  gland-like  bodies,  and  small 
spaces  or  cells,  which  several  anatomists  say  they  have  remarked,  in  which  the  fluid  is 
secreted  and  taken  up  by  the  absorbents,  or  the  finest  branches  of  the  arteries  in  the 
spleen  pass  immediately'into  the  absorbents,  and  by  this  means  some  parts  of  the  arte- 
rial blood  reach  the  absorbents.  From  a  consideration  of  all  the  facts  obtained  by 
themselves  and  former  investigators,  they  infer  that  a  connexion  subsists  between  the 
splenic  arteries  and  absorbents,  either  directly,  or  indirectly,  by  means  of  cells.  The 
secretion  of  this  reddish  coagulating  lymph  from  the  arterial  blood  takes  place,  in  their 
opinion,  from  the  nerves  h^ing  excited,  particularly  during  digestion  :  and  consequent- 
ly, by  the  plentiful  secretion,  the  course  of  the  blood  is  carried  forward  in  the  spleen, 
which  by  this  means  is  reduced  in  size.  3d,  That  this  secreted  coagulable  lymph,  when 
conveyed  into  the  thoracic  duct  is  intended  to  render  the  chyle  similar  to  the,f  blood. 
They  consider  this  inference  to  be  proved  by  at  least  two  circumstances  ;  1st,  That 
this  change  actually  takes  place,  for  the  chyle  of  the  thoracic  duct  differs  from  the 
chyle  of  the  mesenteric  vessels,  by  a  closer  resemblance  to  perfect  blood  :  3d,  That 
when  this  coagulable  matter  was  by  any  means  prevented  from  reaching  the  thoracic 
duct,  this  change  did  not  take  place.  Amongst  other  proofs  which  Professor  Tiede- 
mann and  Gmelin  adduce  in  support  of  these  circumstances,  they  show  that  the  chyle 
taken  from  the  absorbents  of  the  intestinal  canal,  before  they  had  passed  through  the 


OF  THE  INTESTINAL  CANAL,  &c.  ,}3 

mesenteric  glands,  is  always  white  and  has  no  tinge  of  red,  and  either  undergoes  no 
coagulation,  or  does  so  very  feebly  and  slowly.  The  same  fact  has  been  previously 
shown  by  various  anatomists,  and  similar  appearances  to  those  which  are  now  to 
be  noticed  have  been  remarked  by  Dr.  Prout.  Professor  Tiedemann  and  Gmelin  al- 
ways observed  that  this  fluid,  when  it  is  taken  from  the  absorbents  which  had  passed 
out  of  the  mesenteric  glands,  is  redder,  and  coagulates  more  easily  and  more  firmly  than 
the  other :  and  that  the  chyle  in  the  thoracic  duct,  above  the  entrance  of  the  splenic 
absorbents,  and  after  being  mixed  with  the  reddish  coagulable  lymph,  appears  the  red* 
dest,  and  coagulates  very  rapidly.  The  gradual  change  of  the  chyle  into  blood,  they 
argue,  seems,  therefore,  to  be  a  consequence  of  its  passage  through  the  mesenteric 
glands,  and  of  the  admixture  of  the  reddish  coagulable  lymph  supplied  by  the  absor- 
bents of  the  spleen. 

««  The  properties  of  the  spleen  in  the  foetus,  and  in  old  age,  support  this  view,  In 
tfce  foetus  the  spleen  is  known  to  be  very  small,  and  no  chyle  is  formed  in  the  intesti- 
nal canal  in  this  stage  of  existence ;  the  spleen,  accordingly,  intended  to  assimilate  the 
alimentary  matter  derived  from  the  intestinal  canal,  is  of  no  importance.  After  birth, 
when  the*  formation  of  the  chyle  begins,  this  organ  shows  itself  full  of  blood,  and  in- 
creases in  size  rapidly.  In  old"  persons,  the  spleen  is  commonly  diminished  :  it  appeal's, 
therefore,  like  the  lymphatic  glands,  to  decrease  in  size  with  age." 

In  order  to  establish  the  second  circumstance  which  supports  their  third  conclusion, 
professors  Tiedemann  and  Gmelin  had  recourse  to  direct  experiment,  which  fully  prov* 
ed  its  accuracy.  They  conclude  by  observing,  that  pathology  furnishes  many  confirma- 
tions of  their  opinion  ;  and  they  adduce  the  instances  of  scrofula,  diseases  of  the  chy^ 
iopoietic  viscera  in  general,  intermittent  fever,  and  abdominal  dropsy* , 


Of  the  Mucous  Coat  of  the  Digestive  Canal,  and  the  Functions  of  the  aancttt 

and  large  Intestines* 

Note  Oo 

The  mucoua  membrane  of  tfie  Digestive  Tube  has  an  amphorous  and  spongy  structure, 
more  or  less  soft,  and  of 'variable  thickness.  The  free  surface  of  this  membrane  pre- 
sents,— 1st.  Valyules  formed  of  folds  of  this  membrane,  of  the  submucous  tissue,  and 
of  muscular  fiures  contained  within  these  folds ;  2d,  more  or  less  evident  depres- 
siqns,  which  are  generally  infundibuliform,  cellular,  or  alveolar ;  the  follicles  differ  but 
little  from  the  alveolar  depressions  ;  they  have  a  narrow  neck,  more  or  less  lengthened, 
and  a  dilated  body  lodged  in  the  submucous  tissue.  They  are  formed  of  this  membrane 
turned  back  upon  itself,  and  exteriorly  surrounded  by  dense  cellular  tissue  Supplied 
with  numerous  capillaries.  They  vary  greatly  in  number  in  different  situations  ;  3d, 
small  eminences  called  papillae,  and  villosities  which  are  situated  on  the  unattached  sur- 
face of  the  membrane.  These  assume  various  forms,  but  in  general,  those  in  the  pylo- 
ric  extremity  of  the  stomach  and  in  the  duodenum,  being  more  broad  than  long,  present 
a  laminated  appearance ;  those  of  the  jejunum  are  long  and  straight,  and  are  correctly 
called  villosities,  whilst  towards  the  end  of  the  ileum,  and  the  colon,  they  reassume  the, 


*  The  nerves  of  the  spleen  are  chiefly  from  the  cceliac  plexus,  and  form  a  reticulum. 
around  the  splenic  artery,  accompanying  this  vessel  in  all  its  distributions  ;  a  very  few 
minute  nerves  also  come  from  the  par  vagum  and  inosculate  with  those  of  the  cceliac 
plexus. 

M.  Defermon  recently-  found,  in  his  experiments  on  the  abdominal  circulation,  that 
the  spleen  is  susceptible  of  contraction  under  the  influence  of  various  substances  which 
act  directly  on  the  nervous  system,  such  as  strychnine,  camphor,  acetate  of  morphine, 
&c.  In  dogs  to  which  he  had  giren  strychnine,  the  spleen,  which  is  usually  flat,  rolled 
itself  into  a  spiral  form  when  absorption  commenced,  and  presented  very  energetic 
contractions.  The  action  of  camphor  was  different :  the  spleen  under  its  influence 
became  rugous,  and  its  surface  assumed  a  granulated  appearance,  producing  a  degree 
of  motion  in  the  whole  organ. 

The  influence  of  these  agents  on  a  viscus,  whose  nerves  are  nearly  exclusively  be- 
longing to  the  ganglial  system,  confirms  our  views  respecting  the  extent  of  function, 
v;hich  we  have  attributed  to  this  system. 

E 


34  APPENDIX. 

laminated  character.  The  Villosities,  are  semi-diaphanous,  their  surface  is  smooth,  with- 
out any  appearance  of  a  cellular  or  vascular  texture,  both  of  which  have  been  impu- 
ted to  them.  Professor  Meckel,  whilst  he  doubts  whether  or  not  they  possess  either  the 
one  species  of  structure  or  the  other,  is  inclined  to  believe,  from  analogy  with  certain 
parts  of  some  vegetables,  that  they  consist  of  a  continuous  series  of  cells. 

The  villosites  of  the  mucous  membrane  of  the  intestinal  canal  appear  to  be  a  mode  of 
Structure  which,  as  well  as  that  of  folds,  gives  an  increase  of  the  extent  of  surface  exposed 
to  the  influence  of  external  agents.  "  Villosities  are  only  more  minute  forms  of  membran- 
ous folds,  differing  somewhat  from  the  latter  in  the  greater  proportion  of  the  extent  of 
their  surface  to  that  of  their  base,  and  thus  presenting  where  they  exist, — which  is 
chiefly  in  the  small  intestines, — the  means  by  which  the  above-mentioned  purpose  may 
be  most  perfectly  fulfilled." 

The  epidermis,  or  epithelium,  is  very  manifest,  at  the  openings  into  the  digestive  ca- 
nal, but  soon  becomes  much  less  so,  as  we  advance  into  the  cavities,  until  it  becomes 
entirely  indemonstrable.  The  blood  vessels  and  absorbents  of  this  membrane  are  abun- 
dant. Its  nerves  are  chiefly  of  the  ganglial  system,  but  at  its  natural  openings  they  come 
also  from  the  cerebro-spinal  system. 

The  functions  of  the  mucous  membrane  of  the  digestive  tube  may  be  enumerated  un- 
der the  following  heads. 

1.  Absorption,  of  which  the  Villosities  are  the  most  active  agents,  although  not  the 
only  agents. 

2.  Secretion,  which  is  perspiratory  and  follicular ;  and  of  which  the  products  differ- 
ing much  according  to  the  situation  whence  they  issue,  are  generally  known  under  the 
term  mucosity. 

3.  Tonic  contraction,  which  is  promoted  by  the  action  of  the  muscular  fibres. 

4.  Sensibility,  varying  in  all  its  grades,  and  modes  of  manifestations. 

The  mucous  membrane  of  the  intestinal  canal  is  next  to  the  first,  if  not  the  first  of  the 
structures  of  the  body  which  comes  into  existence.  Its  characters  are  but  little  modi- 
fied by  age  or  sex.  (See  the  Note  in  the  Jlppendix,  on  the  Devclopement  of  the  Textures 
of  the  Foetus.) 

Of  the  Digestive  process  in  the  Intestines. — It.  is  not  necessary  to  say  much  in  addition 
to  what  is  contained  in  the  text.  This  process,  as  it  respects  the  whole  apparatus  des- 
tined for  its  performance,  may  be  divided  into  three  stages, — namely,  Chymifaction, 
Chylifaction,  and  Fecation  :  the  first  is  performed  in  the  stomach,  the  second  in  the 
small  intestines,  and  the  third  in  the  large  intestines  The  first  has  already  come  be- 
fore us,  and  the  second  was  noticed,  when  the  functions  of  the  liver  were  under  consi- 
deration. We  may,  however,  remark,  respecting  chylifaction,  that  it  is  by  no  means  a 
chemical  process,  for  there  subsists  no  chemical  relation  between  the  chyme  and  the 
biliary  and  pancreatic  juices,  which  are  the  materials  of  the  ne\v  product ;  this  process 
Is  altogether  a  vital  one,  and  the  result  is  very  nearly  alike  under  every  circumstance. 
Chylifaction  chiefly  takes  place  in  the  duodenum  and  jejunum  from  the  admixture  of  the 
juices  just  now  mentioned  with  the  chyme.  The  experiments  of  Professor  Mondini 
confirm  the  inference,  that  the  duodenum  is  distended  with  the  chyme  when  the  bile  is 
•passing  into  it. 

The  absorption  of  the  chyle  commences  about  the  end  of  the  duodenum,  and  goes  on 
throughout  the  jejunum,  and  the  first  half  of  the  ilium,  and  is  completed  at  the  termi- 
nation of  this  intestine ;  this  function  takes  place  with  greatest  activity  in  the  je- 
junum. 

To  the  function  of  the  larger  intestines  may  be  given  the  term  Fecation ;  because  it 
is  in  this  situation  of  the  digestive  canal  that  the  foccal  matter  is  formed.  In  its  course 
through  the  small  intestines  the  alimentary  matters  are  deprived  of  their  chyle,  and  of 
a  portion  of  their  more  aqueous  parts  :  the  residue  is  poured  into  the  colon,  where  its 
course  is  more  slow  and  where  it  assumes  new  characters.  The  fecal  mass,  according  to 
the  properties  which  it  presents  a"t  the  commencement  of  the  colon  is  evidently  composed 
*— 1st,  of  the  residue  of  the  aliments ;  and  2d,  of  the  excrementitial  parts  of  the  secre- 
tions poured  into  the  superior  part  of  the  digestive  tube.  The  fasces,  when  they  arrive 
in  the  rectum,  or  at  the  time  of  their  expulsion  from  the  body,  are  greatly  increased  by 
the  more  solid  parts  of  the  secretions  poured  out  upon  the  internal  surface  of  the  co- 
lon, their  more  fluid  parts  having  been  absorbed.  It  is,  in  some  measure,  owing  to  the 
quantity  and  properties  of  the  excrementitial  parts  of  these  latter  secretions,  which  prin- 
cipally proceed  from  the  follicular  apparatus  of  this  intestine,  that  the  fseces  present 
distinctive  characters. 

Gaseous  substances  generally  are  found  in  greater  or  less  abundance  in  the  small  in- 
testines. This  gas  may  come  from  more  than  one  source :  it  may  arise  from  the 
change  which  the  elementary  substances  undergo  in  their  course ;  or  it  may  be  secre- 


OF  TUB  FUNCTIONS  OF  THE  KIDNIES  ££ 

ted  by  the  mucous  membrane  of  the  intestines  themselves.  While  we  would  not  al- 
together deny  a  snare  in  its  production  to  the  former,  we  contend  for  the  latter.  We 
believe  that  the  mucous  membrane  of  the  digestive  canal  may  both  secrete  gaseous  sub- 
stances and  absorb  them  ;  and  we  found  our  belief  upon  the  following  circumstances: — 
1st,  We  have  proofs  derived  from  experiment  and  observation  that  gaseous  substances 
are  absorbed  and  given  oft'  from  the  mucous  membrane  of  the  respiratory  apparatus. 
2d,  Pathological  facts  intimately  connected  with  the  functions  and  properties  of  this 
membrane  in  different  parts  of  the  body,  support  the  position.  We  have,  however,  no 
doubt  that  the  changes  ^hich  the  alimentary  substances  undergo  in  the  stomach  occasi- 
onally gives  rise  to  gaseous  products;  and  we  believe  that  a  similar  result  follows  the 
remoVa  of  the  excrernentitial  matters  in  the  colon  and  rectum.  As  to  the  chemical  cha- 
racters of  the  gaseous  substances  found  in  different  parts  of  the  intestinal  tube,  see 
Chapter  II, 


Of  the  Functions  of  the  Kidneys, 

Note  P. 

The  latest,  and,  we  think,  the  most  correct  examination  of  the  intimate  structure  of 
the  kidnies  was  given  in  the  text.  We  now  add  the  ktest  experiments  which  have  been 
made,  in  order  to  ascertain  the  extent  of  their  functions.  Messrs.  Dumas  and  Prevost,  of 
Geneva,  and  afterwards  Mr.  Segales,  of  Paris,  found  on  examining  the  blood  of  living 
animals,  whose  kidnies  had  been  extirpated,  that  it  contained  urea*,  the  quantity  of 
which  was  increased  in  proportion  to  the  duration  of  life  after  the  operation  ;  whilst 
this  substance  could  not  be  detected  in  the  blood  of  those  animals  in  which  the  urinary 
secretion  was  uninterrupted.  The  last  mentioned  physiologist,  moreover,  having  in- 
jected an  aqueous  solution  of  urea  into  the  veins  of  an  animal,  observed  the  secretion  of 
urine  rapidly  increased  by  it,  this  substance  so  quickly  eliminated  in  the  process  that, 
after  twenty -four  hours,  it  could  not  be  detected  in  the  blood.  It  seems,  therefore, 
not  improbable  that  the  debris  of  the  textures,  being  carried  into  the  circulation,  is  con- 
verted by  the  influence  of  the  organs  and  vessels  through  which  it  flows  into  the  sub- 
stance called  urea,  and  that  the  function  of  the  kidnies  is  to  eliminate  it,  with  other 
materials  which  would  be  hurtful  to  the  system.  These  experiments,  show  that  the  urea 
is  not  formed  in  the  kidnies  by  their  appropriate  functions,  as  was  believed  by  some  phy- 
siologist, but  that  it,  and,  probably  other  materials  which  are  removed  from  the  blood 
by  these  organs,  are  deriverd  from  other  sources. 

The  following  facts  more  closely  relate  to  pathology,  than  to  physiology. 

In  inflammatory  fever  the  urine  is  red  or  deep  coloured,  or  even  a  deep  brown,  and 
perfectly  transparent  until  the  disease  tends  to  a  termimation ;  it  then  deposits  the  la- 
terititious  sediment,  which  is  of  a  reddish  colour,  and  consists  of  animal  matter,  phos- 
phate of  lime,  lithic  acid,  and  sometimes  lithate  of  ammonia,  According  to  i)r.  Prout 
lithateof  soda,  and  phosphates  of  ammonia  and  soda,  are  also  present.  In  intermittents 
the  appearance  of  the  urine  varies  according  to  the  stage  of  the  desease  ;  but  when  a 
paroxysm  of  ague  is  over,  what  is  then  voided  deposits  a  peculiarly  red  powder,  which 
has  been  examined  by  Dr.  Prout,  and  found  to  be  a  distinct  acid,  which  he  named  ros- 
acic  acid,  from  its  colour.  In  typhus  fevers,  the  urine  is  loaded  with  gelatin  and  urea. 
It  deposits  in  gouty  disorders,  as  it  cools,  a  large  quantity  of  lithic  acid,  in  the  form  of 
red  crystals.  The  urine  in  hysteria  is  of  a  very  pale  colour ;  it  contains  abundance  of 
saline  ingredients,  but  is  very  deficient  in  urea  and  animal  matter.  In  jaundice  it  is 
usually  of  a  brown  colour,  arising  from  an  admixture  of  bile.  In  various  other  disor- 
ders, especially  those  affecting  the  secreting  function  of  the  liver,  more  particularly 
\rhen  that  function  is  imperfectly  performed,  the  urine  very  generally  presents  a  brown 
and  muddy  appearance,  owing  to  the  kidnies  having  assumed  an  action  in  some  degree 
vicarious  of  that  of  the  liver,  and  thus  removed  much  of  the  carbonaceous  and  effete 
materials  from  the  blood  usually  eliminated  by  that  viscus.  A  similar  appearance  of  the 
tirine  is  often  met  with  in  those  fevers  wherein  the  functions  of  the  liver  are  much  em- 
barrassed, especially  in  those  fevers  called  bilious,  and  in  those  which  are  met  with  in 
warm  climates-  In  ascites  this  fluid  frequently  assumes  a  yellowish  green  colour,  and 
is  extremely  viscid.  It  deposits  a  copious  sediment  of  rosacic  acid  mixed  with  lithic 
acid,  phosphate  of  lime,  and  animal  matter ;  and  is  often  loaded  with  albumen  to  such 

*  Five  PI.  in  res  of  blood  contain  one  scruple  cf  urea, 


36  APPENDIX 

a  degree,  as  to  deposit  it  wheii  heated,  or  on  the  addition  of  concentrated  sulphuric  acid. 
Those  appearances,  however,  are  not  constant,  they  are  more  generally  met  with  in  the 
acute  forms  of  dropsy.  In  some  cases  of  rickets,  the  urine  has  been  found  saturated 
to  a  high  degree  with  phosphate  of  lime.  Its  character  in  diabetes  is  well  known. 
Blood  is  frequently  found  in  the  urine ;  it  gives  this  secretion  more  or  less  of  a  dark 
colour  and  muddy  sediment.  Mucus  is  also  met  with  in  this  fluid,  during  diseases 
affecting  either  the  kulnies,  the  raucous  membrane  of  the  bladder,  or  the  prostate 
gland. 

Of  Absorption. 
Note  Q. 

L  Of  Absorption  fram  the  Digestl-oe  Canal  It  appears,  from  the  experiments  of  Tie* 
demann  and  Gmelin  on  absorption,  that  the  lacteals  take  up  the  digested  and  dissolved 
portions  of  alimentary  substances,  and  convey  them  as  a  chyle  through  the  thoracic 
duct  to  the  blood-vessels :  but  as  odoriferous,  colouring,  and  some  saline  substances, 
are  not  absorbed  by  them,  and  yet  are  found  in  the  blood  of  the  vena  portse,  and  in  se- 
creted fluids,  it  must  necessarily  follow,  that  there  must  be  some  other  way  than  the 
thoracic  duct,  by  which  they  pass  into  the  blood. 

The  following-  are  the  chief  suppositions  which  have  been  offered  in  explanation  of 
the  facts: — "  Either  all  the  lacteals  do  not  enter  the  thoracic  duct,  and  part  of  them 
join  the  veins  which  form  the  vena  portae,  and  thus  transmit  their  contents  into  the 
blood  of  the  vena  portae ;  or  substances  pass  directly  from  the  stomach  and  intestinal 
canal  into  the  veins ;  or  finally,  both  of  these  suppositions  may  be  true." 

These  physiologists  found,  that  quicksilver  injected  into  the  absorbents  of  the  intes» 
tinal  canal  easily  reached  the  mensenteric  veins  and  the  vena  portse,  and  this  communi- 
cation was  found  to  take  place  in  the  mesentedc  glands.  By  means  of  this  communica- 
tion they  explain  the  appearance  of  streaks  of  a  substance  like  chyle,  which  is  perceiv- 
ed in  the  blood  of  the  vena  portae  after  taking  food — a  fact  which  has  been  frequently 
observed  by  other  anatomists. 

Though  the  passage  of  chyle  into  the  vena  portae,  may  be  explained  by  this  connec- 
tion of  the  absorbents  with  the  veins  of  the  intestines,  it 'would  appear  from  the  experi- 
ments, that  the  passage  of  odorous  colouring  and  saline  substances,  does  not  take  place 
in  the  same  way.  The  presence  of  alcohol,  gamboge,  indigo,  could  never  be  detected 
in  the  lacteals,  or  thoracic  duct,  though  it  was  abundantly  manifest  in  the  blood  of  the 
mesenteric  veins,  and  in  the  vena  portae.  They  therefore  conclude,  that  the  passage  of 
these  substances  must  be  effected  through  other  channels,  and  that  these  channels  must 
be  the  radicles  of  the  veins  of  the  intestines.  It  was  found,  on  examining  blood  taken 
from  a  branch  of  the  mesenteric  vein  of  a  dog,  to  which  sulphuro-prussiate  of  potass 
had  been  given,  that  no  streaks  of  chyle  were  present,  but  the  saline  matter  was  per- 
ceived. From  this,  and  other  experiments,  they  conclude  that  the  veins  of  the  intes- 
tines appear  particularly  to  absorb  heterogeneous  substances,  such  as  those  already  par- 
ticularized, whilst  the  lacteals  take  up  nutritious  matter  ;  and  consequently,  that  sub- 
stances taken  into  the  digestive  canal  may  pass  into  the  mass  of  blood — 1°,  through  the 
absorbents,  and  the  thoracic  duct;  2°,  through  absorbents,  which  are  united  with  veins 
in  the  mesemeric  gland;  3°,  through  the  radicles  Or  the  commencement  of  the  mesen- 
teric veins  which  ultimately  form  the  vena  port*. 

,  And  it  seems  established  by  the  experiments,  that  the  vena  portae  receives  chyle 
from  the  absorbents,  and  other  substances  which  are  taken  up  from  the  intestinal 
canal  by  the  veins  themselves,  and  as  the  blood  of  the  vena  portse,  into  which  these 
materials  are  conveyed,  passes  through  the  liver,  this  viscus  must  be  regarded  as  an 
organ  of  assimilation  as  well  as  of  secretion.  See  the  Note  01*  the  Functions  of  the 
Liver.  App.  p.  25. 

II.  Of  Absorption  in  the  Lung's. — Professor  Mayer,  of  Bonne,  infers,  from  experi- 
ments instituted  in  order  to  ascertain  to  what  extent  absorption  takes  place  from  the 
lungs — 

1°.  That  animals  support  a  considerable  quantity  of  liquid  injected  into  the  lung's, 
\vithout  experiencing  mortal  symptoms  from  them ;  but  these  injections  should  DC 
performed  by  an  opening  made  in  the  trachea. 

2°.  The  symptoms  of  suffocation  which  arise  from  injections  are  not  serious  when 
\ve  inject  pv.re  water  ;  but  they  become  so  when  thick  fluids,  for  example,  oil  which 
obstructs  the  aerial  passages,  or  some  chemical  eolations,  which  inflame  tho  bronchial 
surfaces,  ftre  employed  in  this  manner. 


OP  ABSORPTION.  37 

3°.  The  fluid*  and  solutions  injected  into  the  lungs  are  absorbed  more  or  less  quick- 
ly, according  to  their  nature,  and  their  degree  of  concentration. 

4U»  This  absorption  is  in  general  very  great,  but  is  less  in  young  and  newly  born 
animals  than  in  adults. 

5°.  Absorption  takes  place  by  the  pulmonary  veins,  for  it  has  occurred  in  the  space 
of  three  minutes ;  the  fluids  injected  are  found  in  the  blood  before  they  are  perceived 
in  the  chyle  ;  they  are  found  in  the  chyle  :  they  are  found  in  the  left  auricle.  Lastly, 
absorptio'n  is  carried  on  even  although  the  thoracic  duct  be  tied. 

6°.  Absorption  is  likewise  performed  by  the  lymphatic  vessels,  but  more  slowly. 

7Q.  The  veins  of  the -stomach  and  intestines  also  absorb,  but  in  much  smaller  quan- 
tities. 

8°.  The  existence  of  fluids  absorbed  by  the  veins  can  be  demonstrated  in  the  blood. 
It  is  easy  to  discover  there  the  prussiate  of  potass,  the  muriate  of  iron,  arsenic,  &c. 
The  prussiate  of  potass  injected  into  the  lungs  can  be  traced,  first  in  the  arterial  blood 
of  the  heart  and  arteries,  then,  if  the  injection  be  continued,  in  the  venous  blood. 

9Q.  These  substances  can  be  discovered  in  abundance  in  the  urine  in  the  bladder, 
and  in  that  in  the  kidneys.  The  prussiate  of  potass  can  be  discovered  in  it  seven  mi- 
nutes after  the  injection. 

10°,  The  prussiate  of  potass  is  likewise  deposited,  and  even  in  considerable  quan- 
tity, in  the  serum  of  the  pericardium,  of  the  pleura,  of  the  peritonaeum,  in  the  synovia, 
under  the  skin,  and  in  the  milk. 

liy,  When  the  prussiate  of  potass  is  injected,  it  can  be  discovered  after  some  hours, 
not  only  in  the  fluids,  but  also  in  many  of  the  solids  :  several  of  these,  parts  then  be- 
come green  or  blue  with  the  muriate  of  iron,  viz.  the  cellular  tissue  uHder  the  skin, 
and  in  the  whole  body,  the  fat,  the  serous  and  fibrous  membranes,  the  aponerouses  of 
the  muscles,  tendons,  the  dura  mater,  periosteum,  &c. 

12°.  The  membranes  of  the  arteries  and  veins  5  even  the  valves  of  the  heart  can  be 
thus  entirely  coloured  blue  by  the  same  agent. 

15°.  The  parenchyma  of  the  liver  and  spleen  cannot  be  coloured  blue,  but  some- 
times the  cellular  tissue  around  their  great  vessels.  The  lungs,  the  heart,  and  the  kid- 
neys, can  be  coloured  blue. 

15°.  The  substance  of  the  bones  and  their  marrow,  the  substance  of  the  muscles 
and  that  of  the  brain,  spinal  marrow,  and  nerves,  evince  no  change  of  colour  with 
the  muriate  of  iron.  The  nerves  of  the  brain  and  spinal  marrow  seem  to  exert  a  re- 
pulsive and  exclusive  force,  on  the  contact  of  fluids  foreign  to  their  nutrition.  It  may 
be  concluded  from  this  that  the  opinions  of  many  physiologists,  that  poisons  act  mor- 
tally, when  they  are  applied  to  these  parts  of  the  nervous  system,  are  not  well  founded, 
and  are  devoid  of  direct  proofs. 

16°.  These  experiments  may  also  throw  some  light  on  secretion,  the  reproduction 
and  nourishment  of  bodies  ;  they  teach,  moreover,  the  passage  of  liquids  from  the  mo- 
ther to  the  foetus.  When  the  prussiate  of  potass  has  been  administered  to  the  mother, 
it  can  be  detected  in  the  water  of  the  amnion,  in  that  of  the  chorion,  and  of  the  um- 
bilical vesicle,  in  the  liquid  of  the  stomach,  in  many  solid  parts  of  the  foetus,  for  ex- 
ample, in  the  kidneys,  in  the  stomach,  &c.  as  also  in  the  placenta.  When  a  foe- 
tus, to  the  mother  of  which  prussiate  of  potass  has  been  given,  is  placed  into  a  mixture 
of  spirit  of  wine  and  muriate  of  iron,  it  becomes  blue  coloured.  Thus  we  acquire  a 
certain  proof  of  the  passage  of  fluids  from  the  mother  to  the  fcetus,  a  proof  that  has 
been  vainly  sought  for  until  now  : — the  fluids  taken  into  the  blood  of  the  mother  are 
deposited  in  the  tissue  of  the  placenta,  and  are  thence  absorbed  by  the  veins  of  the 
foetus* 

FIL  Of  the  manner  in  which  Absorption  in  performed;  andef  Exhalation. — M.  Magen- 
die  (Journal  de  Physiol,  Experiment.  JVo.  I.}  infers  that  the  chyhferous  vessels  absorb 
chyle  only,  and  that  the  veins  possess  the  faculty  of  absorption.  He  has  endeavoured 
to  disprove  the  absorbent  power  of  the  lymphatic  vessels,  but  in  this  lie  has  not  suc- 
ceeded. He  considers  also  that  his  experiments  justify  him  in  concluding,  that,  in  all 
cases  where  artificial  or  real  plethora  exists,  and  the  veins  consequently  are  distended, 
no  absorption  takes  place,  or  only  in  a  slight  degree,  and  after  a  greater  lengt.li  of  time, 
than  under  ordinary  circumstances  ;  whilst,  when  the  original  quantity  of  blood  is  di- 
minished by  venesection,  absorption  follows  in  one-fourth  of  the  time  in  which  it  is 
found  to  occur  when  depletion  has  not  been  previously  had  recourse  to.  He  considers 
it  therefore,  to  follow,  that  absorption  is  influenced  by  the  congestion  and  caliber  of 
the  blood-vessel;}. 

"  The  further  pursuit  of  these  researches  led  M.  Magendie  to  the  conclusion,  -that 
absorption  is  nothing  more  than  the  well-known  phenomena  of  capillary  contraction* 
which  takes  place  vhen  tubes  Of  a  smell  rnlibre  are'  immersed  in  fluids: a  pheno- 


38  APPENDIX; 

menon  whose  energy  is  in  a  direct  ratio  of  the  affinity  of  the  fluid  for  the  surface  of  the 
tube, — and  in  an  inverse  ratio  with  the  diameter  of  the  latter. 

"  It  appears  to  me  then,'*  he  adds,  "  beyond  doubt  that  all  the  blood-vessels,  venous 
and  arterial,  whether  duad  or  living,  small  or  great,  present,  in  their  parietes,  a  physical 
property  calculated  to  account  for  the  principal  phenomena  of  absorption.  To  affirm 
that  this  property  is  alone  able  to  produce  all  the  phenomena  of  absorption  would  be  to 
go  beyond  what  is  warranted  by  a  correct  logic  ;  but  in  the  present  state  of  facts  on  the 
subject,  I  know  not  any  thing  which  weakens  the  inference  which  I  have  drawn,  but- 
many  which  may  be  adduced  in  its  support." 

"  By  this  method  of  explaining  absorption,"  he  observes,  ts  we  solve  a  number  of 
other  phenomena  in  the  living  system  otherwise  inexplicable  :  for  example,  the  princi- 
ple on  which  dropsies  are  cured,  the  relief  from  congestion  and  inflammation  produced 
by  blood-letting,  the  want  of  efficacy  in  medicines  during  those  febrile  states  of  the  sys- 
tem in  which  the  vascular  system  is  greatly  distended:  the  propriety  of  that  practice 
which  institutes  blood-letting  and  purging  prior  to  the  administration  of  other  active 
medicinals,  the  rationale  of  both  partial  and  general  dropsies,  under  circumstances  of 
cardiac  or  pulmonary  diseases ;  the  use  of  ligatures  upon  limbs  after  the  bite  of  veno- 
mous animals,  in  order  to  prevent  the  consequences  of  such  accidents,"  &c. 

That  absorption  takes  place  exclusively  through  the  medium  of  the  veins  cannot,  in 
our' opinion,  be  granted  to  any  part  of  the  body  or  to  any  organ,  excepting  to  the  brain. 
As  respects  this  organ,  we  believe  that  sufficient  proofs  exist  of  this  function  being1 
performed  entirely  by  this  set  of  vessels.  {See  t/tc  Note  on  the  Structure  and  Functions 
of  the  Jfiwin.') 

This  very  interesting  subject  has  been  further  investigated  by  Messrs.  Segales  and  Fo- 
dera.  Journ.  de  PhysioL  .April  1822,  and  Jan.  1823.)  The  latter  physiologist  entered 
upon  a  series  of  experiments,  which,  although  they  appear  not  to  us  fully  to  substaniate 
the  opinion  of  Magendie  that  venous  absorption  takes  place  by  capillary  attraction, 
seem  nevertheless  to  show  that  this  process,  or  one  similar  to  it,  actually  exists  to  a 
certain  extent  in  the  living  body,  and  that  though  it  may  be  subordinate  to  more  ener- 
getic influences,  it  should  not  be  altogether  overlooked  in  our  inquiries  into  the  ope- 
rations of  the  animal  economy. 

Mr.  Fodera's  end,  in  his  experiments,  has  been  to  demonstrate  that  exhalation,  which 
he  calls  transudation :  and  absorption,  which  he  names  imbibition,  are  similar  phenomena, 
owing  to  the  capillary  attraction  of  the  parietes  of  the  different  vessels,  owing  to  their 
porosity,  operating,  in  the  first  case,  from  the  interior  of  the  vessels  to  the  exterior,  and 
in  the  second  from  the  exterior  to  the  inferior. 

Magendie  conceived  he  had  already  proved  that  venous  absorption  takes  place  by 
imbibition,  and  came  to  the  conclusions  which  we  have  now  stated.  One  of  his  experi 
ments  consisted  in  completely  isolating  a  portion  of  vein,  and  placing  its-  surface  in 
contact  with  an  active  poison  :  its  presence  was  soon  discovered  at  the  internal  surface 
of  the  vessel.  M.  Fodera  then  inverscd  the  experiment.  He  injected  a  poisonous  sub- 
stance, with  every  proper  precaution,  into  the  interior  of  a  portion  of  artery  comprised 
between  two  ligatures,  and  isolated  frcm  its  cellular  tissue,  its  lymphatics,  and  its  vasa 
vasomm  .-  poisoning  took  place.  He  obtained  the  same  result  by  filling  with  poison  a 
portion  of  an  artery,  vein,  or  of  intestine,  removing  and  placing  them  either  at  the  sur- 
face of  a  wound  made  in  another  animal,  or  in  the  abdominal  cavity.  In  these  different 
experiments,  the  rapidity  ot  the  poisoning  appeared  to  vary  according  to  the  age  and 
kind  of  animal ;  the  thickness  and  length  of  the  portion  of  vessel  or  intestine,  its 
greater  or  less  distension  :  the  more  or  less  perfect  solution  of  the  injected  matter,  &c. 

Mr.  Fodera  has  also  seen  gases  absorbed  in  the  same  manner.  He  placed  on  the  pe- 
ritoneal cavity  of  a  rabbit  sulphurretted  hydrogen,  enclosed  in  a  portion  of  intestine  re- 
moved from  another  animal ;  and  at  the  end  of  some  time,  symptoms  of  poisoning  ma- 
nifested themselves,  and  the  sulphurretttd  hydrogen  was  no  longer  found  in  the  intes- 
tine. 

If,  in  a  living1  animal,  an  artery  or  vein  is  exposed,  an  oozing  is  observed  to  take  place 
through  its  parietes.  This  oozing  augments,  if  a  ligature  be  applied  to  the  vessel :  dif- 
i'erent  dropsies  may  likewise  be  produced  by  the  ligature  of  the  great  venous  trunks. 

Mr.  Fodera  concludes,  from  these  facts,  that  exhalation  is  only  a  phenomenon  of 
transudation  through  the  parietes  of  tjie  vessels,  as  many  physicians  had  thought,  be- 
fore the  exhalent  vessels  were  imagined. 

The  following  experiments  prove  that,  at  least,  on  the  dead  body,  transudation  of  li- 
quids may  take  place  at  the  same  time  from  the  interior  to  the  exterior,  and  rice  versa 
through  the  vascular  or  intestinal  parietea.  Fodera  filled  a  portion  of  a  rabbit's  in- 
testine v.'Uh  a  solution  of  prussiate  of  potass,  and  plunpred  it  into  a  solution  of'hydrochlo- 


OP  ABSORPTION.  ^Q 

rate  of  lime  :  he  Introduced  into  another  portion  some  hydrochloric  acid  and  surround- 
ed  it  with  sulphuric  acid ;  finally,  he  placed  a  bladder,  filled  with  tincture  of  turnsol, 
in  a  solution  of  gall  nuts.  Sometime  afterwards  he  found  in  the  interior  of  these  por- 
tions of  the  intestine  and  of  the  bladder,  hydrochlorate  of  lime,  sulphuric  acid,  and  gal- 
lic acid,  by  the  tests  of  nitrate  of  silver,  hydrochlorate  of  barytes,  and  sulphate  of  iron; 
and  in  the'  liquids  in  which  they  had  been  immersed,  prussiate  of  potass,  hydrochloric 
acid,  and  tincture  of  turnsol,  by  the  tests  of  sulphate  of  copper,  the  nitrate  of  silver,  and 
by  the  reddish  colour  of  the  solution  of  galls  being  rendered  bluish  by  the  potas.s. 

On  injecting  at  the  same  time  into  the  pulmonary  vein  of  a  sheep,  a  solution  of  hy- 
drochlorate of  barytes,  and  one  of  the  hydrocyanate  of  potass  into  the  trachea,  Fo- 
dera  also  found  hydrocynute  of  potass  in  the  pulmonary  artery,  and  hydrochlorate  of 
barytes  in  the  bronchia:. 

Similar  phenomena  may  be  produced  upon  a  living  animal,  Fodera  has  found,  for 
example,  in  the  bladder  or  in  the  thorax,  substances  which  had  been  injected  into  the 
peritoneum  ;  and  in  the  abdominal  cavity,  substances  which  had  been  introduced  into 
the  thorax  or  bladder.  In  these  experiments  he  employed  the  solution  of  gall  and  sul- 
phate of  iron,  or  rather,  the  latter  salt  and  prussiate  of  potass. 

The  black  or  blue  colour,  announcing  that  transudation  has  taken  place,  is  frequently 
not  observed  until  the  end  of  more  than  an  hour :  it  may  be  rendered  almost  instantane- 
ous by  putting  in  action  the  galvanic  influence.  For  this  purpose,  this  ingenious  expe- 
rimenter injects  into  the  bladder,  or  into  a  portion  of  the  intestine  of  a  living  rabbit,  a 
solution  of  prussiate  of  potass,  communicating  with  a  copper  wire  ;  externally,  he  places 
a  cloth  wet  with  a  solution  of  the  sulphate,  communicating  with  an  iron  wire  :  these 
wires  are  put  in  contact  with  those  of  the  pile.  If  the  galvanic  stream  be  directed  from 
the  exterior  to  the  interior,. by  making  a  communication  between  the  iron  wire  and  the 
positive  pole,  and  between  that  of  copper  and  the  negative,  the  tissues  of  the  organs  im- 
bibe the  Prussian  blue  :  if  the  stream  be  changed,  the  colour  appears  on  the  cloth. 

M.  Fodera  injected  into  the  left  cavity  of  the  thorax  of  a  rabbit  a  solution  of  hydrocy- 
anate of  potass,  and  into  the  peritoneum  a  solution  of  sulphate  of  iron ;  he  afterwards 
kept  the  animal  placed  on  its  left  side  for  three  quarters  of  an  hour.  At  the  end  of  this 
period  the  animal  was  opened,  when  he  found  that  the  whole  of  the  tendinous  part  of 
the  diaphragm  had  imbibed  the  blue  matter;  the  muscular  part  was  much  less  tinged, 
and  only  in  isolated  points.  The  substernal  lymphatic  glands  were  likewise  blue. 
The  thoracic  duct  contained  a  bluish  liquid  :  the  peritoneal  membrane  of  the  stomach, 
and  duodenum  was  coloured  with  spots  of  the  same  colour  :  they  were  observable,  but 
in  less  number,  on  the  rest  of  the  digestive  canal  and  on  the  arteries.  The  lymphatic 
glands  of  the  mesentery,  the  suspensory  ligament  of  the  liver,  the  epiploon,  were  also 
tinged  blue.  Some  small  subperitoneal  veins  presented  a  slight  blue  colouration  of  the 
liquid  contained  in  their  interior.  Twelve  hours  afterwards,  the  blue  tint  of  these  dif- 
ferent parts  was  much  more  intense. 

The  progress  of  the  colouration  may  be  traced,  and  the  phenomenon  in  some  measure 
be  seen  in  its  different  phases  t  by  injecting  a  femiretted  solution  of  prussiate  of  potass 
into  a  portion  of  the  intestine  of  a  living  animal ;  tying  both  ends,  and  plunging  it  into 
a  bath  containing  sulphate  of  iron.  At  first  a  slight  coloration,  only,  is  observable  in  the 
parts,  which  gradually  becomes  deeper  :  afterwards  the  liquids  of  the  lymphatics  and 
of  the  blood-vessels  become  coloured  in  turn.  In  these  latter,  the  coloration  begins 
by  small  ramifications,  and  afterwards  extends  to  the  branches,  which  are  observed  to 
be  tilled  with  intervals  of  blood  and  a  blue  liquid.  In  these  experiments  Fodera 
discovered  the  presence  of  the  prussiate  of  iron  in  the  lymphatic  vessels,  in  the  thoracic 
duct,  and,  finally,  in  the  portion  of  the  inferior  vena  cava  contained  in  the  chests. 

Mr.  Fodera  concludes,  from  these  different  experiments,  1st,  that  exhalation  and  ab- 
sorption take  place  by  transudation  and  imbibition,  and  depend  on  the  capillarity  of  the 
tissues  ;  2dly,  that  th'is  double  phenomenon  may  take  place  in  every  part,  and  that  the 
liquids  imbibed  may  be  conveyed  equally  well,  either  by  the  lymphatic  vessels,  or  by 
the  arterial  or  venous.  But  (the  author  very  wisely  adds)  the  phenomena  of  exhalation 
and  absorption  ought  not  to  be  considered  as  connected  alone  with  imbibition  and  tran- 
sudation :  the  modifications  which  they  experience  from  the  action  of  surrounding- 
agents,  from  the  nervous  influence,  the  state  of  rest  and  motion,  the  energy  of  the  cir- 
culation, the  affinities  of  the  substances  with  the  tissues,  the  derangements  produced  by 
disease,  and  the  elaboration  which  the  fluids  undergo  whilst  absorption  and  exhalation 
are  taking  place,  ought  likewise  to  be  studied. 

Mr.  Fodera  endeavours  to  explain  the  increase  of  exhalation  in  the  phlegmasiae  by 
the  dilatation  which  the  parietes  of  the  capillary  vessels  experience  ;  the  interstices  of 
the  fibres  which  form  these  parietes  become  at  such  times  increased,  and,  consquently, 
permit  a  more  ready  issue  to  the  fluids :  the  serosity  and  the  white  globules,  which  are 


40  APPENDIX, 

smaller  than  the  red,  are  first  effused ;  at  lost  the  red  globules  themselves  occasionally 
escape.  It  will  be  seen  that  this  mode  of  conceiving-  the  phenomenon  does  not  explain 
the  infinite  modifications  which  the  liquids  exhaled  into  the  inflamed  parts  undergo. 

Mr.  Fodera  notices  cases  in  which  the  lymphatics  or  thoracic  duct  have  been  said  to 
contain  different  substances,  which  had  been  introduced  either  into  the  digestive  ca- 
nal, the  serous  cavities,  or  into  the  cellular  tissue.  If  the  effects  of  absorption  are  not 
manifested,  in  the  experiments,  where  a  portion  of  intestine,  containing  poison,  has  no 
longer  any  communication  with  the  rest  of  the  body,  except  by  a  lymphatic  vessel,  we 
must  seek  for  a  cause  in  the  extreme  slowness  of  the  circulation  of  the  lymph.  M.  Fo- 
dera inserted  some  liquid  prussiate  of  potass  in  the  subcutaneous  cellular  tissue  of  the 
thigh  and  abdomen  of  two  young  rabbits.  In  the  first  animal,  at  the  expiration  of  a  few 
minutes,  and  in  the  second,  at  the  end  of  half  an  hour,  he  found  it  in  the  lymph  of  the 
thoracic  duct,  in  the  urine,  the  mucous  of  the  intestines,  the  synovia,  the  s'ermn  of  the 
blood,  the  serosity  of  the  pericardium,  of  the  pleura,  and  of  the  peritoneum,  as  well  as 
in  all  the  solid  parts,  except  in  the  crystalline  lens,  the  cerebral  substance,  the  interior 
of  the  nerves,  and  the  ossous  tissue.  In  another  experiment  the  interior  of  the  nerves 
presented  traces  of  it. 

Would  not  these  experiments  tend  to  prove  that  absorption  in  these  cases  had  ta» 
ken  place  at  tbe  same  time,  both  by  the  lympatica  and  blood-vessels  ? 

While  the  German  physiologists  have  ascribed  absorption  to  the  absorbents  and  veins 
only,  Messrs.  Magendie  and  Fodera  have  extended  this  function  to  the  arteries  also.  In 
this,  however,  we  think  that  they  have  been  misled  by  fallacies  which  had  crept  into 
then-  experiments,  and  especially  by  the  unnatural  position  and  deranged  actions  which 
the  operations  and  agents  required  by  the  experiments  induce  in  the  animal  and  in  the 
parts  experimented  on.  From  every  consideration  we  are  led  lo  infer,  that  the  infer- 
ences at  which  Tiedemann,  Gmelin,  and  Mayer  have  arrived,  approach  the  nearest  to 
truth. 

The  experiments  performed  by  Darwin,  and  more  recently  by  Wollaston,  Brande, 
and  Marcet,  tend  to  prove  that  different  substances  introduced  into  the  stomach  are 
found  mixed  with  the  urine,  without  having  passed  by  the  lymphatic  or  blood-vessels. 

Fodera  has  repeated  these  experiments,  and  made  them  undergo  an  ingenious 
modification,  which  has  discovered  to  him  phenomena  unobserved  by  former  physiolo- 
gists. He  introduced  into  the  bladder  a  plugged  catheter,  after  having  tied  the  penis  in 
order  to  prevent  the  urine  from  flowing  along  the  sides  of  the  sound.  He  laid  bare  the 
oesophagus  at  the  anterior  part  of  the  neck,  and  injected  into  the  stomach  a  solution 
containing  some  grains  of  the  ferruretted  hydrocyanate  of  potass.  This  being  done, 
he  frequently  removed  the  plug,  and  received  on  filtering  paper  the  urine  which  es- 
caped. On  this  paper  he  dropped  a  solution  of  sulphate  of  iron,  and  added  to  it  a  little 
hydrochloric  acid  in  order  to  destroy  the  color.  In  one  experiment  the  prussiate  was 
detected  in  the  urine  ten  minutes  after  its  injection  into  the  stomach,  and  in  another 
live  minutes  afterwards.  The  animals  were  opened  immediately.  The  salt  was  found 
5n  the  serum  of  the  blood  taken  from  thethorac  portion  of  the  vena  eava  inferior,  in  the 
right  and  left  cavities  of  the  heart,  in  the  aorta,  the  thoracic  duct,  the  mesenteric 
glands,  the  kidnies,  the  joints,  and  the  mucous  membrane  of  the  bronchia:. 

This  important  experiment  proves  the  extreme  rapidity  of  absorption  ;  it  shows  also 
that  the  prussiate  of  potass  found  in  the  urine,  is  conveyed  thither  by  the  ordinary  cir- 
culating ways. 

The  following  experiment  demonstrates  the  rapidity  of  pulmonary  absorption  in  par- 
ticular. Fodera  opened  the  thorax  of  a  rabbit,  and  removed  the  heart,  immediate- 
ly after  some  prussiate  of  potass  had  been  injected  into  the  trachea.  This  operation  was 
performed  in  twenty  seconds :  the  interior  of  the  left  auricle,  however,  presented  a 
bluish  green  colour,  which  was  more  deep  at  the  mitral  valve  and  les»  apparent  in  the 
aorta.  The  absorption,  therefore,  seems  to  take  place  at  the  very  instant  when  the  in- 
jection  has  penetrated  into  the  subdivisions  of  the  bronchia. 

We  are  of  opinion,  that  to  limit  the  process  of  absorption  in  every  part  of  the  body, 
and  under  every  combination  of  circumstances  to  which  it  is  subject,  to  one  particular 
process,  or  to  one  particular  conformation  or  property  which  the  vessels,  whether  blood- 
vessels, or  others,  may  possess,  would  in  the  present  state  of  our  knowledge,  be  to 
draw  an  inference  not' justified  by  many  important  facts.  On  the  contrary,  it  seems  more 
probable  that  not  only  the  vital  properties,  but  those  of  a  physical  nature,  are  requisite 
to  the  production  of  "the  phenomena  in  question;  and  that  the  Jatter  set  of  properties 
are  under  the  control  of  the  former. 

Instead  of  attempting  to  show  that  those  physical  properties  for  which  Messrs.  Magen- 
die and  Fodera  have  contended,  are  not  to  a  certain  degree  efficient  in  the  production  of 
the  process  in  question,  \ve  would  only  argue  for  their  subordinate  character,  which  may 


OF  ABSORPTION. 


41 


be  in  support  of  his  purely  physical  properties ;  but,  although  the  vital  properties  arc 
chiefly  predominant  in  the  operation,  yet  those  for  which  they  contend  may  have  still 
a  place  to  a  certain  extent,  which  extent  is  modifiexl  by  a  superior  influence. 

Investigations  into  the  process  of  absorption  have  also  been  entered  upon  in  America. 
Doctors  Lawrance,  Coates,  and  others,  made  thirty-four  experiments  in  which  the  prus- 
siate  of  potass  was  introduced  into  the  alimentary  canal :  from  these  it  appears  that  ar- 
ticles taken  into  the  stomach  may  be  conveyed  into  the  circulation  by  three  channels ; 
namely,  the  vena  portae,  the  oesophageal  veins  and  the  thoracic  duct,  and  if  all  these 
are  closed,  the  absorbed  matters  are  no  longer  conveyed  to  the  circulation  or  to  the^ 
urine.  With  regard  to  the  quantity  conveyed  b\  each,  they  had  no  accurate  means  of 
judging.  As  the  quantity  of  fluid,  however,  contained  in  the  vena  portarum,  is  so  much 
greater  than  in  the  thoracic  duct,  it  follows,  that  to  produce  a  colour  of  equal  in- 
tensity, a  much  larger  amount  of  the  colouring  matter  is  requisite,  and,  as  the  serum  ot 
the  blood  of  the  vena  port®  gave  an  equally  deep  colour,  the  greater  proportion  of  the 
materials  must  have  been  absorbed  through  the  veins  contributing  to  this  system  of 
vessels. 

In  consequence  of  reading  the  experiments  of  professor  Mayer  of  Gottingen,  upon 
absorption  in  the  lungs,  Doctors  Lawrance  and  Coates  made  a  few  with  that  reference. 

The  animals  generally  died  in  about  a  minute  after  the  injection,  from  suffocation, 
by  the  ligatures  which  they  placed  on  the  tracheas  of  most  of  them.  These  experiments, 
\ve  think,  go  to  favour  the  ideathat  absorption  from  the  mucous  membrane  of  the  lungs, 
is  performed  principally  by  the  pulmonary  veins.  They  lay  particular  stress  upon  ex- 
periments 5th  and  6th.  In  the  first,  the  blood  from  the  left  side  of  the  heart  indicated 
the  agent  in  much  larger  proportion  than  that  from  the  right  side,  both  being  examined 
about  the  same  time  :  viz.  seven  minutes.  In  the  second,  where  the  examination  was 
made  in  a  much  shorter  period,  viz.  three  minutes  and  a  half,  and  four  minutes  and  a 
half,  the  article  was  distinctly  found  in  the  left  side  of  the  heart  before  it  had  arrived 
in  any  other  part  of  the  system. 

The  effect  of  infiltration  was  also  remarkable  in  these  experiments. 

The  results  of  five  trials  of  the  prussiate  in  the  cavity  of  the  abdomen  are  here  arranged 
for  inspection. 


Animals. 

Quantity. 

Thoracic  Duct. 

Carotid  and 
Jugular. 

Urine. 

Kitten. 

^oz.  solu- 
tion. 

12  &  13  m. 
distinct  blue. 

6  m.  distinct 
blue. 

19  m.  no  blae. 

Idem. 

Idem. 

4  m.  blue. 

2  m.  no 
blue. 

10  or  15  m.  no 
blue.  29  m.  distinct 
blue. 

Idem. 

Idem, 
nearly. 

3|  m.  blue. 

2  m.  no 
blue. 

5  m.  blue,  not 
strongly. 

Idem. 

ioz. 

3  m.  blue. 

4  m.  strongly 
blue. 

More  than  4  m. 
doubtful. 

Cat. 

Uncertain. 

9£  m.  blue. 

5  m.  no  blue. 

More  than  9^  m. 
no  blue, 

The  short  time  in  which  the  prussiate  reached  the  upper  part  of  the  thoracic  duct  in 
the  above  cases,  induced  them  to  make  four  other  trials  in  order  to  ascertain  the  earli- 
est period  at  which  that  took  place.  Half  an  ounce  of  solution  was  employed  in  each 
case. 

In  the  first  animal,  a  kitten,  the  salt  first  arrived  at  the  spot  of  observation  in  four 
minutes,  and  the  quantity  gradually  increased  till  seven  or  eight  minutes.  In  the 
second  kitten,  it  appeared  in  two  minutes,  The  serum  of  this  animal  gave  a  blue 
tinge.  In  the  third  kitten,  in  three  minutes  and  a  half.  Serum  of  blood  also  blue.  In 
the  cat,  it  first  appeared  in  thirteen  minutes. 

In  these  cases,  the  thoracic  duct  was  cut  off  near  its  insertion ;  and  the  test  applied 

F 


42  APPENDIX. 

there.  In  consequence  of  this  interruption,  previously  to  the  prussiate  arriving  at  the 
upper  extremity  of  the  duct,  the  discovery  of  the  salt  in  the  serum  of  the  blood  clearly 
evinces  that  it  was  conveyed  there  by  other  channels. 

It  is  mentioned  by  Magendie,  that  he  has  seen,  on  pressing  the  lacteal  branches  so 
as  to  discharge  their  contents  in  the  direction  of  the  trunks,  that  those  branches  would 
again  fill  themselves  after  the  animal's  death.  They  have  also  witnessed  these  appear- 
ances ;  but  they  do  not  know  of  any  similar  observations  to  the  following  made  on  the 
lymphatics,  or  of  any  evidence  of  the  actual  chemical  presence  of  an  article  conveyed 
after  death  into  either  of  these  systems  from  without. 

Four  kittens  were  bled  to  what  is  commonly  considered  death.  The  blood  ceased 
to  flow  from  the  divided  carotid,  and  voluntary  motion  was  extinct.  Prussiate  of  potass 
in  solution  was  then  thrown  into  the  abdomen.  It  appeared  at  the  thoracic  duct  in  five 
and  a  half,  five,  fourteen,  and  twelve  minutes  respectively.  In  the  two  last,  the  great 
vessels  originating  at  the  heart  were  secured  by  a  common  ligature.  The  blue  colour 
was  in  every  instance  perfectly  distinct. 

In  reasoning  on  the  subject  of  absorption,  the  question  has  frequently  arisen,  whe- 
ther the  articles  found  in  the  living  fluids  exist  there  as  chemical  substances,  or  have 
their  chemical  nature  altered  and  animalized  by  the  action  of  the  vessels  through  which 
they  have  entered  the  system.  It  was,  however,  deemed  a  curious  subject  of  inquiry, 
whether  artificial  chemical  changes  can  take  place  in  the  fluids  while  they  continue  to 
circulate  in  living  vessels,  and  the  ordinary  actions  of  life  go  on.  With  a  view  of  as- 
certaining this  point,  they  commenced  by  throwing  prussiate  of  potass  into  the  abdo- 
men, and  green  sulphate  of  iron  into  the  cellular  tissue,  in  order  to  try  whether  the 
well  known  result  of  their  admixture,  the  prussian  blue,  would  be  produced  in  the  ves- 
sels. This,  however,  did  not  take  place  :  and  they  resolved  to  repeat  it  by  throwing 
the  sulphate,  as  the  article  of  more  difficult  absorption,  into  the  abdomen,  where  this 
process  went  on  with  more  facility,  and  the  prussiate  into  the  cellular  substance.  On 
performing  this,  they  were  gratified  by  the  striking  result  of  a  distinct  and  beautiful  blue 
in  the  thoracic  trunk,  and  its  contents,  and  in  nearly  the  whole  substance  and  surface 
of  the  lungs.  These  viscera  were  preserved  in  spirits,  and  are  now  in  their  possession. 
The  blood  threw  up  a  coagulum  of  a  strong  blue  colour,  and  the  lymph  and  chyle  from 
the  thoracic  duct,  threw  down  a  blue  deposit.  Thus  not  only  a  foreign,  but  a  pulveru- 
lent substance  could  present  its  unnatural  stimulus  and  circulate  through  the  vessels, 
and  accumulate  in  the  lungs,  without  preventing  the  actions  of  life  from  considerable 
exertion,  and  without  occasioning  coagulation  of  the  blood.  The  animal  manifested  some 
difficulty  of  respiration  before  she  was  killed,  but  walked  about  without  the  least  diffi- 
culty, and  uttered  no  cries,  nor  other  signs  of  disturbance  of  its  powers.  In  another 
case,  the  urine  and  lungs  were  noted  as  exhibiting  a  blue  colour.  The  other  parts  si- 
milar to  those  above  enumerated,  are  not  described  as  being  found  coloured.  In  a 
third,  the  fluid  in  the  thoracic  duct  was  blue,  but  not  the  other  fluids  examined,  nor  the 
lungs.  Two  unsuccessful  trials  were  also  made.  In  another  case  the  thoracic  duct  was 
tied,  and  the  same  process  repeated.  A  divided  bluish  green  was  here  found  in  the 
urine ;  but  neither  the  serum  of  the  arterial  blood,  nor  the  lymph  of  the  ductus  tho~ 
racicus,  manifested  the  blue  or  green. 


Of  tlte  Mion  of  the  Heart  and  Arteries. 
NoteR. 

I.  Of  the  Heart. — The  muscular  fibres  of  the  heart  are  more  apparent  in  the  foetus 
than  in  the  adult ;  it  only  participates  in  the  general  paleness  of  muscular  textures  at 
that  epoch,  although  it  is  deeper  coloured  than  they  are.  It  also  is  entirely  without  fat  at 
this  period.  In  old  age  the  texture  of  the  heart  becomes  softer  and  more  flaccid  than 
in  the  young  subject,  and  its  parietes  thinner  :  its  cavities  enlarge,  especially  the  right, 
and  its  surface  is  more  charged  with  fat. 

The  nerves  of  the  heart  have  been  a  subject  of  interest  with  physiologists.  Since 
they  were  investigated  by  Scarpa  opinions  have  been  tolerably  uniform  respecting  them; 
and  numerous  observers  have  proved  the  general  accuracy  of  his  researches.  The 
cardiac  nerves  are  chiefly  derrived  from  the  ganglia  of  the  great  sympathetic  :  a  few 
also  come  from  the  pneumo-gastric ;  but  these  seem  rather  to  inosculate  with  the  for- 
mer, than  to  go  directly  to  the  texture  of  the  organ.  The  cardiac  ganglion,  situated 


OF  THE  ACTIONS  OF  THE  HEART  AND  ARTERIES.      43 

behind  this  organ,  seems  more  particularly  to  preside  over  its  movements,  or  to  rein- 
force with  additional  energy  whatever  it  may  receive  from  other  sources,  especially 
from  the  centre  of  the  ganglial  system  and  the  other  ganglia  in  the  neck  and  chest. 
These  nerves,  according  to  our  own  observations,  supply  the  substance  of  the  heart  in 
two  ways : 1st,  There  are  numerous  branches  which  proceed  from  the  different  plex- 
uses directly  to  its  muscular  texture,  and  which,  dipping  between  the  fibres,  give 
off'  minute  fibrillae  to  these  fibres  next  to  them  in  the  course  of  their  descent  into 
the  substance  of  the  heart.  2d,  A  large  portion  also  of  the  nerves  of  the  heart  form 
an  t  nvelope  of  the  coronary  arteries.  A  part  of  these  seem  to  follow  the  arteries 
throughout  their  distributions ;  but,  before  the  coronary  arteries  have  ramified  to  a 
great  extent,  a  part  ot  the  nerves  surrounding  them  is  detached  to  the  adjoining  parts, 
so  that  all  the  nerves  which  surround  these  arteries,  like  a  reticulum  or  sheath, 
do  not  accompany  the  ramifications  of  the  latter  to  their  ultimate  subdivisions  and  ter- 
minations in  the  veins,  a  portion  of  them  appearing  to  be  detached  in  numerous  and 
minute  fibrillse  to  the  immediately  adjoining  fibres.  Thus  it  will  be  perceived  that  the 
muscular  texture  of  the  heart  receives  directly  and  mediately  a  very  considerable  por- 
tion of  ganglial  nerves  ;  whilst,  it  may  be  presumed,  that  it  also  receives  an  accession  in 
those  fibrils  which  terminate  with  the  nutritious  capillaries  in  this  particular  structure 

The  functions  of  the  heart,  it  may  reasonably  be  supposed,  are  chiefly  the  result  of 
the  influence  which  this  disposition  of  the  ganglial  system  of  nerves  bestows  on  its 
structure.  In  addition  to  the  support  which  this  inference  derives  from  the  conforma- 
tion of  the  viscus  and  its  relation  with  the  rest  of  this  particular  system  of  nerves,  both 
n.  man  and  the  lower  animals,  experiments  which  have  been  performed  by  different 
physiologists,  prove  its  accuracy*  ;  and  prove  it  the  more  conclusively,  inasmuch  as 
they  were  performed  with  a  view  of  establishing  a  different  proposition. 

But,  although  the  heart  derives  its  chief  influence  from  the  ganglial  system,  it  is 
ucted  on  through  the  medium  of  the  nerves  which  communicate  between  this  system 
and  the  cerebro-spinal,  and  which  seem  to  convey  an  additional  influence  from  the  lat- 
ter, to  the  ganglia  and  plexuses  which  immediately  supply  the  heart.  And  as  this 
communication  is  more*  intimate  in  the  more  perfect  animals,  and  the  functions  of  the 
cerebro-spinal  system  are  more  energetic  in  them,  so  it  appears  to  follow  that  the  heart's 
action  is  more"  readily  influenced  either  by  the  increase  or  diminution  of  these  func- 
tions in  them,  than  in  the  lowest  order  of  animals. 

Another  point  to  which  it  is  necessary  to  advert,  is  the  question  as  to  the  active  dila- 
tion of  the  heart— a  function  of  this  viscus  much  insisted  on  by  Hamberger,  and  more 
recently  by  Carson  and  others.  We  doubt  not  that  it  actually  exists  to  some  extent, 
in  all  animals  provided  with  a  perfect  heart,  but  we  do  not  believe  that  it  takes  place 
with  great  energy.  If  the  dilation,  however,  of  the  heart,  were  a  mere  result  of  a  re- 
laxation of  its  fibres,  its  cavities  could  not  be  so  quickly  and  perfectly  filled  by  the 
mechanical  pressure  of  the  blood  directed  towards  them,  as  we  observe  that  they  are  ; 
and  dilation  would  be  only  the  consequence  of  this  pressure,  and  be  proportionate 
to  it.  But  this  is  not  the  case  ;  for,  as  far  as  we  could  judge  from  observing  the  cir- 
culation in  fishes,  the  dilation  seems  to  precede  the  flow  of  blood,  the  latter  appearing* 
as  a  consequence  of  the  former. 

Allowing,  therefore,  that  the  dilation  of  the  cavities  of  the  heart  takes  place  to  a 
certain  extent — an  extent  which  it  is  difficult  fully  to  determine,  but  which  we  consi- 
der much  less  than  that  contended  for  by  Hamberger  and  Carson,  one  of  the  causes  ct" 
the  flow  of  blood  in  the  large  veins  will  be  apparent. 

The  heart  is  perfectly  insensible  in  its  natural  state.  This  was  satisfactorily  shown  in 
an  operation  performed  by  ML  Richerand,  in  1813,  wherein  he  divided  the  ribs  and  re- 

*  Willis  divided  the  eight  pair  of  nerves  in  the  neck  with  a  view  of  paralysing  the 
action  of  the  heart,  but  death  did  not  supervene  until  some  hours,  and  in  some  casee, 
not  until  several  days,  after  the  operation.  In  the  experiments  of  Legallois  and  Dr. 
Phillips,  destruction  of  the  brain  and  spinal  marrow  did  not  necessarily  and  immediately 
put  a  stop  to  the  action  of  this  viscus  :  although,  as  should  be  expected,  it  was  greatly 
influenced  by  the  privation  of  a  necessary  and  an  accustomed  influence.  In  experi- 
ments which  were  performed  on  several  species  of  fishes,  the  actions  of  the  heart  con- 
tinued long  after  the  destruction  of  the  cerebro-spinal  masses,  and  frequently  for  u 
short  time  after  it  was  removed  from  the  body.  Lastly,  foetuses  have  been  born,  in 
which  the  action  of  the  heart  and  circulation  were  perfect,  although  tiiey  wanted  both 
brain  and  spinal  cord  :  and  many  of  the  lower  classes  of  animals  have  continued  to  !;' ,. 
for  a  very  considerable  time  after  decapitation, 


44  APPENDIX, 

moved  a  portion  of  scirrhous  pleura,  thus  allowing  the  pericardium  to  be  expo&ecL- 
The  patient  was  perfectly  insensible  of  any  impression,  when  M.  Iticherand  touched 
this  organ,  although  the  pericardium,  the  part  through  which  it  was  handled,  is  evi- 
dently the  must  sensible  part  of  it  during  disease  :  in  a'state  of  disease  its  organic  sen- 
sibly becomes  indistinctly  and  obscurely  developed. 

TI.  Of  the  Arteries. — The  arteries  throughout  the  body  are  smTOunded  by  the  gan- 
glial  nerves.  These  nerves  form  a  reticulum  around  them,  from  which  reticulum  very 
minute  fibrillse  are  given  off  and  dip  into  their  fibrous  or  muscular  tunic. 

This  particular  disposition  of  the  ganglial  nerves  on  the  arteries  ought  to  be  kept  in 
recollection  when  we  inquire  into  the  functions  of  the  latter.  How  far  it  tends,  not 
only  to  the  discharge  of  the  more  manifest  actions  which  the  arterial  system  performs, 
bvit  also  to  those  insensible  changes  which  the  blood  undergoes  in  health  and  in  dis- 
ease, and  to  the  assimilation  of  the  chyle  and  other  absorbed  materials  conveyed  into 
this  fluid,  we  have  ventured  to  state  at  another  place.  We  shall  here  merely  take  no- 
tice of  an  opinion  relative  to  the  operations  of  this  class  of  vessels  in  the  circulation  of 
the  blood,  lately  contended  for  by  M.  Magendie.  This  physiologist  has  inferred  from 
his  researches  on  the  circulation, — 

*<  1.  That  neither  the  larger  nor  the  smaller  arteries  present  any  trace  of  irritability. 

«  2.  That  they  are  dilated  during  the  heart's  systole. 

"3.  That  they  are  capable  of  contracting  themselves  with  sufficient  force  on  the 
blood  they  contain,  so  as  to  propel  it  into  the  veins. 

"  4.  That  the  blood  in  the  arteries  is  not  alternately  at  rest  and  in  motion  ;  but  that 
it  is,  on  the  contrary,  in  a  continued  succedaneous  (by  little  jets)  motion  in  the  trunks 
and  ramifications — and  uniform  in  the  smallest  ramifications  and  divisions. 

«  5.  That  the  contraction  of  the  left  ventricle  of  the  heart,  and  the  elasticity  of  the 
larger  and  smaller  arteries,  furnishes  a  satisfactory  mechanical  reason  for  these  pheno- 
mena, 

"  6.  That  the  contraction  of  the  heart  and  arteries  has  a  considerable  influence  on  the 
coxirse  of  the  blood  through  the  veins." 

We  cannot  concur  in  these  conclusions,  especially  in  the  sweeping  inference  which 
forms  M.  Magendie's  fifth  proposition  :  and  we  might,  were  it  consistent  with  our  limits, 
point  out  various  fallacies  in  his  experiments,  to  some  of  which,  indeed,  all  experiments 
on  living  subjects  are  more  or  less  liable,  viz.  the  unnatural  position  of  the  animal  dur- 
ing their  performance,  and  more  particularly  as  respects  the  operations  of  the  part  im- 
mediately its  subject.  If  M.  Magendie  limits  the  process  to  the  mechanical  means  in- 
dicated above,  we  would  ask,  how  he  accounts  for  the  influence  of  mental  emotions  in 
determining  the  action  of  the  vessels  in  particular  parts  of  the  body  ?  How  the  diversi- 
fied influences  of  numerous  external  agents  on  the  circulation  can  be  explained  ? 
Wherefore  so  very  opposite  effects  are  produced  upon  the  arteries,  when  one  extremity 
is  placed  in  a  pail  of  ice,  and  another  in  a  pail  of  warm  water  ?  How  can  he  reconcile 
his  conclusions  with  the  very  satisfactory  experiments  performed  by  Sir  Everard  Home, 
Dr.  Hastings,  and  others  ?  and  how  he  can  account  for  the  determinations  of  blood  to 
particular  parts,  whilst  a  diminishing  quantity  is  sent  to  other  situations  ? — if  he  discard 
lite  predominating  or  vital  power  which  the  vessels  themselves,  and  especially  their 
smaller  ramifications  possess  in  virtue  of  the  particular  structure  already  noticed.  We 
readily  grant  that  the  larger  branches  of  arteries  evince  little  or  lio  contractile  action, 
particularly  in  their  natural  state ;  but  we  contend  that  it  increases  as  we  advance  to- 
\yards  the  extreme  capillaries,  the  action  of  which  derives  the  blood  to  them  in  larger 
proportion,  and  thus  increases  both  the  mechanical  and  vital  properties  of  the  larger 
branches  supplying  them. 

We  allow  that  the  properties  for  which  M.  Magendie  contends  have  an  actual  place 
in  the  process  of  arterial  circulation  ;  but  they  are  not  the  only  ones ;  they  are  insufficient 
of  themselves  to  accomplish  the  purposes  which  he  assigns  to  them  ;  and,  moreover, 
they  are  secondary  to,  and  controlled  by,  a  superior  influence. 

From  these  observations  it  may  be  perceived  that  the  arteries  act  in  the  process  of 
the  circulation,  not  by  means  of  a  contractile  action  similar  to  what  is  performed  by  the 
heart  ;  nor  yet  by  means  of  elasticity  only  ,-  but  by  an  organic  or  vital  operation,  which  is 
•nearly  imperceptible  in  the  larger  arterial  branches,  but  which  increases  as  we  advance 
to  the  extreme  capillaries ;  whilst,  on  the  contrary,  the  elastic  or  mechanical  properties 
augment  as  we  proceed  in  the  opposite  direction. 


OF  THE  FUNCTIONS  OF  THE  CAPILLARIES.  45 

Of  the,  Functions  of  the  Capillaries, 
Note  S. 


This  class  of  vessels  may  be  divided  into  two  orders,  performing  distinct  functions  ; — 
1st,  those  capillary  vessels  between  the  terminations  of  the  aortic  arteries  and  the 
commencement  of  the  veins  of  the  body  ;  and  2d,  those  between  the  termination  of  the 
pulmonary  arteries  and  veins  of  the  same  name  The  first  of  these  orders  is  disposed, 
in  different  proportions,  to  the  compound  solids  of  the  body  ;  the  second  is  distributed 
on  the  surface  of  the  air-cells  of  the  lungs  only.  In  the  one  are  performed  changes 
which,  render  the  blood  unfit  for  the  purposes  of  the  animal  economy  ;  in  the  other  takes 
place  an  elaborate  process  of  an  opposite  nature.  In  the  first  are  produced  those  or- 
ganic functions  which  relate  more  directly  to  the  noui'ishment  of  the  frame,  as  digestion, 
secretion,  and  nutrition  ;  in  the  second,  those  preparatory  operations  on  the  blood  which 
enable  the  sensible  and  contractile  textures  of  the  body  to  perform  their  offices.  With- 
out the  accomplishment  of  the  latter,  the  former  could  not  be  performed  :  for,  as  the 
former  depends  upon  the  vital  influence  distributed  to  the  capillaries  and  to  their  re- 
spective  organs,  as  well  as  upon  its  state  in  the  sources  whence  it  is  derived,  so  does 
this  influence  itself  depend  upon  the  operations  which  take  place  in  the  latter  order  of 
capillaries.  The  importance,  therefore,  of  these  operations  in  the  animal  economy  must 
be  manifest,  as  well  as  the  intimate  bond  which  unites  them  throughout  the  frame  : 
without  the  performance  of  the  one  class  of  functions,  the  other  could  not  be  dis- 
charged. 

This  part  of  the  circulation — the  most  interesting,  perhaps  of  any,  to  the  physiologist 
and  pathologist,  without  being  independent  of  the  heart's  action,  is  the  least  under  its 
control ;  the  functions  of  the  capillary  vessels  continuing  to  a  certain  extent,  even  after 
the  heart  has  ceased  to  contract:  and,  asha\e  been  shown  by  some  experiments  per- 
formed in  this  country,  in  France,  and  in  America,  these  actions  are  not  limited,  even 
then,  to  the  mere  circulation  of  the  fluid  which  they  contain  ;  for  under  this  particular 
circumstance,  they  may  also  perform,  for  a  short  time,  the  functions  of  absorption,  and 
secretion. 

These  phenomena  may  be  readily  explained  when  we  consider  two  circumstances  ;— 
1st,  the  source  whence  the  capillaries  derive  their  functions  ;  and  2d,  the  kind  of  death 
which  the  animal  experiences,  and  the  order  in  which  the  different  organs  cease  to  act. 
We  cannot  enter  here  further  into  this  topic ;  we  have  pointed  out  the  way  :  those  who 
are  interested  in  it  will  be  able  to  pursue  it ;  those  who  are  not,  would  profit  little  from 
a  lengthened  explanation. 

Before  we  leave  this  subject  we  may  notice  an  opinion  which  has  been  entertained 
amongst  the  most  eminent  physiologists.  This  relates  to  the  existence  of  subordinate 
sets  of  minute  and  colourless  arterial  capillaries,  each  devoted  to  a  particular  function  ; 
namely,  one  to  nutrition,  another  to  secretion,  and  a  third  and  principal  set,  to  the 
transmission  of  the  red  blood,  which,  in  consequence  of  the  functions  of  the  former  two, 
have  become  possessed  of  venous  properties.  The  first  and  second  of  these  sets  are 
considered  to  be  pellucid  in  their  natural  state,  and,  although  they  cannot  be  satisfac- 
torily demonstrated,  in  this  state,  their  existence  seems  to  be  rendered  probable,  if  not 
proved,  by  many  of  the  phenomena  of  disease  and  by  artificial  injections. 

Dr.  Alard  has  lately  contended  for  the  existence  of  a  similar  set  of  colourless  vessels 
connected  in  the  same  manner  with  the  veins ;  and  that  whilst  those  of  the  arteries 
carry  the  fluids  intended  for  the  nutrition  of  the  textures,  for  the  secretions,  and  exhala- 
tion ;  these  belonging  to  the  veins  perform  the  functions  of  absorption.  Some  of  these 
latter  vessels,  whose  open  mouths  are  present  every  where,  in  the  most  intimate  tex- 
tures of  the  organs,  as  well  as  on  the  surfaces  of  the  great  cavities,  are  supposed  by  Dr. 
Alard  to  terminate  in  the  parietes  of  the  adjacent  veins;  whilst  others  unite  and  form 
the  trunks  which  are  generally  known  by  the  name  of  absorbents.  The  discovery  of 
Dr.  Fohman,  of  Heidelberk,  of  a  communication  of  the  lymphatics  of  the  intestine  with 
the  mesenteric  veins,  in  some  animals,  concurs  to  support  the  proposition  of  Dr.  Alard. 
On  this  subject  Dr.  Hutchinson,  whose  physiological  knowledge  is  of  the  first  order, 
has  justly  observed, — the  view  of  Alard — that  supposing  the  existence  of  minute  pellu- 
cid vessels,  springing  from  the  parietes  of  the  small  arteries;  distributed  to  every  part 
of  the  body;  conveying  different  fluids,  and  producing  different  effects,  according  as 
their  vital  properties  are  modified ;  having  corresponding  vessels,  which  spring  from 
the  most  intimate  texture  of  the  organs  and  surfaces  of  the  great  cavities,  and  umte  in 


46  APPENDIX. 

larger  tubes,  forming1  in  some  instances  long  continuous  canals,  denominated  absorbents, 
in  others  running  to  be  inserted  into  veins, — is  one  which  is.  qualified  to  explain,  more 
plausibly  than  any  other  the  mechanism  of  the  distribution  of  the  fluids  for  the  pur- 
poses of  the  organic  functions ;  and  is,  besides,  capable  of  obviating  the  difficulties 
which  have  been  presented  by  the  diversity  of  the  results  of  the  experiments  of  Hunter, 
Magendie,  Broclie  and  others,  relative  to  the  mechanism  of  absorption*.  (See  the  Note 
on  Jibsorptwn.} 


Of  the  Veins. 
Note  T. 

1.  As  to  the  precise  way  in  which  the  veins  commence,  opinions  have  been  various. 
At  the  place  where  the  capillaries  change  from  arteries  into  veins,  there  appears  to  be 
no  reason  to  suppose  the  existence  of  either   interspace,  or  vesicular  or  spongy  struc- 
ture.    The  inflected  canal  of  the  artery  seems  to  be  continuous  with  the  vein.     Whilst, 
however,  this  conformation  is  allowed  by  nearly  all,  some  consider,  with  Mr.  Ribes,  that 
the  veins  have  another  commencement  in  addition  to  this  ;  and  that  a  certain  proportion 
of  their  roots  commence  in  open  mouths  or  in  the  pores  or  areolse  of  the  luminous  tis- 
sues, and  in  the  substance  of  the  organs.     Others  also  suppose  with  M.  Alard,  (See  the 
preceding  nvte,)  that  some  of  their  roots  commence  in  pellucid  lymphatic  absorbents. 

The  structure  of  the  erectile  tissues,  as  the  penis,  the  clitoris,  the  spleen,  &c.  seems 
to  support  the  opinion  of  Ribes,  (which  is  also  that  of  Meckel,  who  farther  sup- 
poses that  one  cause  of  the  difference  of  the  appearance  and  functions  of  organs  may 
be  ascribed  to  the  extent  to  which  the  veins  originate  in  particular  manner  for  which  he 
contends. 

The  views  of  M.  Alard  derive  their  chief  support  from  the  phenomena  connected 
with  absorption,  but,  although  they  appear  probable,  they  cannot  be  fully  demon- 
strated. 

The  veins  receive  but  a  small  proportion  of  nerves,  and  these  are  chiefly  from  the 
ganglia.  The  nerves  supplying  the  pulmonary  veins  come  principally  from  the  anterior 
pulmonary  plexus. 

2.  '1  '/it  functions  of  the  veins  are — 1st,  to  bring  back  the  blood  from  the  capillaries  to 
the  heart :  2d,  to  remove  and  assist  in  the  assimilation  of  fluids,  which  are  absorbed  by 
the  lacteals  and  absorbents;  and  3d,  in  certain  situations,  and  under  certain  circumstances 
to  co-operate  in  the  function  of  absorption. 

Thejirst  of  the  operations  is  performed  by  means  of  the  vital  action  with  which  the 
veins  are  endowed,  assisted  by  the  vis  a  tergo  proceeding  from  the  vital  action  of  the 
capillaries, — by  the  contraction  of  the  surrounding  muscles  viewed  in  connexion  with 
the  direction  of  the  valves,  with  which  they  are  provided, — and  by  the  active  dilation 
of  ttie  cavities  of  the  heart  which  derives  the  blood  from  the  venous  trunks. 

The  third  action  of  the  veins,  or  absorption,  seems  to  be  proved  by  the  researches 
already  detailed.  (See  Absorption  in  the  Jlppendix.}  The  venous  radicles,  either  im- 
mediately or  mediately,  seize  the  absorbed  materials,  and  convey  them  into  the  current 
of  the  circulation.  This  seems  to  be  a  vital  or  organic  action,  which  is  probably  assist- 
ed,  in  some  parts  of  the  body,  and  under  certain  circumstances,  by  the  physical  property 


*  Admitting  fully  the  justness  of  Dr.  Hutchinson's  remarks,  we  must  observe  that, 
the  existence  of  the  sets  of  capillaries  here  contended  for  by  Dr.  Alard,  is  not  proved 
demonstratively.  Indeed,  we  possess  this  species  of  proof  in  favour  only  of  one  set  of 
capillaries, — namely,  those  winch  constitute  the  termination  of  the  arteries  and  com- 
mencement of  veins.  We  know  that  secretion,  nutrition,  and  absorption,  are  func- 
tions of  capillary  vessels.  This  has  always  been  granted  from  the  time  of  Hippocrates  ; 
but  there  have  been  various  instruments  allotted  to  the  process,  some  physiologists  in- 
sist, with  Dr.  Alard,  upon  the  existence  ol  subordinate  sets  of  capillaries  allotted  to 
each  function,  whilst  others  contend,  with  M.  Richerand,  that  they  take  place  through 
the  medium  of  lateral  pores  in  those  capillaries  which  communicate  directly  between 
the  arteries  and  veins.  These  veins  will  come  under  consideration  in  the  notes  in  this 
Appendix  on  Secretion  and  Nutrition* 


OP  THE  MECHANISM  OF  THE  RESPIRATORY  ORGANS.  47 

of  imbibition  OP  capillary  attraction,  which  all  animal  textures  evince  in  a  greater  or 
less  degree.  It  should,  however,  be  recollected,  that  this  property  is  a  very  subordinate 
one  to  vitality,  is  entirely  under  its  control,  and  takes  place  very  imperfectly  when  this 
influence  is  in  full  vigour, 

The  second  function  of  this  class  of  vessels,  is  the' admixture  of  the  absorbed  mate- 
rials, and  the  assimilation  of  them  The  former  cr  mechanical  part  of  this  function  is 
performed  generally  throughout  the  body,  al  hough  it  takes  place  to  a  greater  extent 
in  some  instances  than  in  others,  as  in  those  viscera  in  which  the  blood  circulates  more 
immediately  after  it  has  received  the  chyle  and  lymph  from  the  lacteal  absorbents  and 
thoracic  duct.  Hence  it  chiefly  takes  place  in  the  heart  itself,  and  in  the  liver  and  lungs. 
The  latter  part  of  this  function  is  essentially  a  vital  one,  and  appears  to  us  to  result 
from  the  vital  influence  derived  from  the  nerves  with  which  the  blood-vessels  are  pro- 
vided. Supposing  this  position  to  be  correct,  we  should  expect  that  the  vessels  in 
which  this  process  takes  place  would  be  most  abundantly  supplied  with  those  nerves, 
whence  we  consider  the  assimilating  influence  to  proceed.  Now  this  is  actually  the 
case,  the  blood  which  is  carried  into  the  portal  veins  contains  a  larger  proportion  of  ab- 
sorbed and  imperfectly  assimilated  materials  than  the  blood  in  any  other  organ ;  and  this 
particular  order  of  veins,  whose  office  it  is  to  assimilate  them,  and  to  eliminate 
the  effoete  elements  from  the  circulating  fluid,  is  provided  with  a  much 
greater  number  of  ganglial  nerves  than  any  other  part  of  the  venous  system ;  and,  in- 
deed, even  more  than  the  arteries  in  some  situations.  This  particular  set  of  veins, 
therefore,  performs  a  double  function,  viz.  of  assimilation,  and  of  secretion ;  in  the  lat- 
ter, however,  it  may  participate  with  the  hepatic  artery  ;  for,  as  the  hepatic  vein  re- 
turns the  blood  of  both  the  vena  portee  and  the  artery,  the  biliary  secretion  may,  pro- 
bably, not  take  place  until  the  terminating  capillaries  of  both  have  given  rise  to  the 
radicles  of  the  vein. 

Assimilation  goes  on,  in  the  next  degree  of  activity,  in  the  lungs,  and  more  or  less 
partially  in  other  organs  of  the  body. 


Of  the  Mechanism  of  the  Respiratory  Organs. 
Note  U. 

I.  Of  the  Structure  of  the  Lungs. — According  to  the  observations  of  M.  Magendie,  the 
cellules  of  the  lungs  do  not  appear  to  be  arranged  in  a  methodical  manner,  nor  to  have 
membranous  parietes.     With  respect  to  the  non-existence  of  the  latter,  we  think  that 
he  was  betrayed  into  error  bv  the  method  of  investigation  which  he  adopted.*     These 
cellules  seemed  to  him  to  be  formed  solely  by  the  minutest  and  last  ramifications  of  the 
pulmonary  artery ;     by  the  radicles  of   the  veins  of  the  same  name,   which  are  a 
continuation  of  the  former,  and  lastly,  by  the  numerous  anastamoses  of  all  these  ves- 
sels.    These  cellules  are  separated  into  many  distinct  lobules,  in  each  of  which  the 
cellules  communicate  among  themselves  ;  while  between  the  lobules  there  is  no  com- 
munication. 

"  The  number  of  cellules  is  in  an  inverse  ratio  to  the  age  of  the  subject ;  consequent- 
ly the  older  the  person,  the  larger  is  each  cellula,  or  what  comes  to  the  same  thing, 
the  fewer  are  the  cellulx. 

*'  It  follows,  therefore,  that  the  lungs  become  specifically  lighter  as  we  advance  in 
fife  ;  and  in  support  of  the  correctness  of  this  inference  Magendie  states  that  he  found, 
by  actual  experiment,  that  in  equal  volumes,  a  portion  of  the  lungs  of  a  man  at  seventy 
was  fourteen  times  specifically  lighter  than  that  of  a  child  a  few  days  old." 

II.  Of  the  Jlctiom  of  the  Glottis — M.  Bourdon,  (Recliei*che6  sur  le  mechanisms  de  la  res- 
wrafc'on,  &c.  Paris,  1820,)  considers  that  the  glottis  performs  the  following  functions^ 

in  addition  to  those  which  are  requisite  to  the  formation  of  the  voice. 

1.  "  That  is  the  glottis  which  suspends  respiration  during  considerable  efforts,  in  op- 
posing, by  its  closure,  the  escape  of  the  air  contained  in  the  lungs. 


*  He  partially  filled  the  lungs  by  insufflation  after  their  removal  from  the  subject, 
and  allowed  them  to  dry.  When  quite  dry  he  found  this  sort  of  preparation  to  be  nearly 
transparent,  and  readilv  cnt  into  thin  slices  ^yith  a  knife- 


4g  APPENDIX. 

2.  "  Without  the  glottis,  the  action  of  the  abdominal  muscles  would  be  constantly  em- 
ployed in  producing  respiration :  neither  compression  of  the  viscera,  nor  flexure  of  the 
trunk  could  be  produced. 

3.  "  There  exists  a  real  co?isensus  of  action  between  the  glottis  and  the  abdominal 
muscles,  and  through  this  medium,  between  the  glottis  and  the  different  reservoirs,  the 
bladder,  the  rectum,  the  stomach,  and  the  uterus. 

4.  « « The  glottis  does  not  confine  its  action  to  the  production  of  the  voice  ;  but  by  the 
aid  of  the  sympathetic  connexions  which  unite  it  to  the  abdominal  muscles,  charged  to 
concur  in,  if  not  to  preside  over  important  functions,  it  excites  the  greatest  influence  on 
those  functions  themselves. 

5.  ««  Lastly,  in  the  different  efforts  there  is  a  tendency  to  expiration,  to  the  produc- 
tion of  which  the  closure  of  the  glottis  is  an  obstacle." 


IIT.  Of  the  Effects  of  Respiration  on  the  Circulation  of  the  Blood.—  The  experiments 
of  Haller,  Lamure,  and  Lorry,  and  subsequently  those  or  Cloquet  and  Bourdon,  have 
shown, 

1.  That,  during  inspiration,  the  blood  of  the  vena  cava,  superior  and  inferior,  is 
drawn  towards  the  heart. 

2.  That,  during  expiration,  the  blood  is,  on  the  contrary,  driven  in  the  same  veins, 
towards  the  viscera. 

3.  That  the  arterial  blood  is  also  driven  towards  the  viscera  at  the  time  of  expira- 
tion. 

4.  That  the  alternate  motions  of  the  brain  is  owing  to  the  changes  caused  by  respira- 
tion in  the  flow  of  blood. 

5.  That  all  these  charges  are  but  little  marked  in  ordinary  respiration  ;  but  that  they 
come  very  evident  in  full  respirations,  and  particularly  so  during  great  efforts. 

6.  Lastly,  that,  during  great  efforts  the  glottis  is  firmly  closed,  the  air  contained  hi 
the  lungs  is  compressed,  as  well  as  all  the  pectoral  and  abdominal  viscera. 

In  order  to  ascertain  the  precise  effects  produced  by  respiration  on  the  venous  cir- 
culation, Magendie  instituted  a  set  of  experiments  from  which  he  draws  the  infer- 
ences, that  respiration  modifies  the  venous  circulation;—!0  by  the  influence  which  it 
exerts  on  the  course  of  the  arterial  blood  ; — 2°  by  its  direct  action  on  the  current  of 
blood  in  the  veins  That  in  profound  respirations  and  violent  efforts,  the  circulation  ap- 
pears nearly  suspended. 


IV.  Of  the  State  of  the  Lungs  during  Respiration.— The  experiments  of  Dr.  Carson 
have  directed  the  attention  of  physiologists  to  the  state  of  the  lungs  themselves  during 
respiration,  and  under  the  various  influences  to  which  they  are  usually  subjected  either 
by  accident,  by  operations,  or  by  disease.  Dr.  Carson  had  inferred  from  his  experi- 
ments, that  it  is  possible  to  collapse  one  of  the  lungs,  and  to  retain  it  in  that  state,  ad 
libitum,  by  keeping  open  the  communication  between  the  cavity  of  the  chest  and  the 
external  air;  and  further,  that  upon  allowing  the  opening  to  close,  the  lung,  in  a  given 
time,  will  recover  its  wonted  function,  thereby  rendering  it  practicable,  when  conceiv- 
ed necessary,  to  place  the  opposite  lung  under  the  like  discipline.  In  order  to  examine 
the  stability  of  these  inferences.  Dr.  David  Williams,  of  Liverpool,  instituted  several 
experiments,  in  the  presence  of  Dr.  Trail  an  i  otliers,  which  contradict  some  of  the  chief 
positions  held  by  Dr.  Carson.  After  detailing  his  experiments,  Dr.  Williams  draws  the 
following  conclusions  from  them. 

"  1.  That  a  lung  will  not  collapse  from  exposure  to  the  atmosphere  as  long  as  respi- 
ration is  carrred  on  by  the  opposite  one,  and  the  auxiliary  respiratory  powers  are  not 
restrained. 

"  2.  That  a  lung  possesses  for  a  time,  independently  of  the  influence  of  the  dia- 
phragm and  intercostal  muscles,  if  respiration  is  carried  on  by  the  opposite  lung,  a  pe- 
culiar motive  power,  the  source  of  which  I  do  not  pretend  to  explain. 

"3.  That  a  sound  lung  soon  regains  its  full  power  of  expansion,  when  the  pressure 
of  the  exterior  air  is  removed. 

"  4.  That  air  freelv  and  uninterruptedly  admitted  into  both  cavities  of  the  chest  si- 
multaneously, through  tubes  of  a  certain  calibre,  will  not  collapse  the  lungs,  if  the  auxi- 
liary respiratory  organs  are  unrestrained. 


QJF  THE  FUNCTIONS  OF  THE  LUNGS.  49 

*'  5.  That  air  admitted  into  both  the  cavities  of  the  chest  (of  a  middle  sired  dog)  si- 
multaneously through  apertures  of  an  inch  and  better  in  length  in  the  intercostal  paces, 
will  not  collapse  the  lungs,  provided  the  animal  is  allowed  unconfined  the  use  of  his  re- 
spiratory organs. 

**  6.  That  a  sound  lung  never  fills  the  bag  of  the  pleura." 


V.  Of  the  Effects  of  Suspended  Respiration  on  the  Circulation. — From  the  experiments 
which  were  made  by  Dr.  Williams,  of  Liverpool,  on  this  subject,  he  deduces  the  fol- 
lowing corollaries  : 

1.  The  blood  is  obstructed  in  its  passage  through  the  lungs,  on  suspension  of  respira- 
tion, while  its  circulation  through  the  other  parts  of  the  body  continues. 

2.  The  obstruction  of  the  blood  in  the  lungs,  on  suspension  of  respiration,  is  not  oc- 
casioned by  a  mechanical  cause.  This  is  proved  by  the  flow  of  blood  through  the  lungs 
being  sudden!     arrested,  without  any  subsidance  of  this  organ,  while  the  circulation 
was  carried  on  vigorously  through  the  other  parts  of  the  body,  in  the  experiments  de- 
tailed by  the  author. 

3.  The  observation  of,bloodin  the  lungs,  on  suspension  of  respiration,  arises  from  the 
deprivation  of  pure  atmospheric  air. 

4.  The  blood,  which  is  found  after  death  in  the  left  auricle  and  ventricle,  is  the  rem- 
nant after  the  last  systole,  and  the  subsequent  draining  of  the  pulmonary  veins. 

5.  The  obstruction  of  blood  in  the  lungs,  on  suspension  of  respiration,  is  one  of  the 
principal  causes  of  the  vacuity  after  death  of  the  system  circulating  arterial  blood. 

6.  The  immediate  cause  of  the  cessation  of  the  action  of  the  heart  is  a  privation  of 
its  natural  stimulus,  arising  from  the  obstruction  of  the  blood  in  the  lungs. — (JInnals  of 
PhUos.  Sept.  18^3.) 


Of  the  changes  induced  on  the  Air  and  the  Blood  by  Respiration* 
Note  W. 

1.  Of  the  production  of  Carbonic  Acid  during  Respiration. — The  experiments  of  Mr. 
Ellis  and  others  have  led  physiologists  to  conclude,  that  oxygen  is  not  absorbed  by  the 
blood  in  the  lungs  from  the  air,  during  respiration,  but  that  the  blood  gives  off  its  su- 
perabundant carbon  from  the  surface  of  the  air-cells  and  the  carbonic  acid  is  thus  form- 
ed in  the  lungs  themselves. 

This  mode  of  accounting  for  the  changes  induced  upon  the  air  and  upon  the  blood 
during  respiration,  has  been  very  generally  adopted  in  this  country,  while  the  former 
mode  of  explaining  the  process  (that  which  is  given  in  the  text)  has  still  been  received, 
with  various  modifications,  on  the  Continent. 

It  appears  to  us  that  the  production  of  carbonic  acid  gas  by  the  respiratory  function 
has  been  ascribed  too  exclusively  to  one  of  the  above  processes  ;  and  that  it  has  been 
too  generally  viewed  as  altogether  a  chemical  phenomenon.  When  the  theory  of  the 
absorption  of  oxygen  was  dismissed  in  favour  of  that  which  contended  for  the  discharge 
of  carbon  from  the  blood,  either  in  its  pure  state  or  in  that  of  a  hydrate,  no  participa- 
tion in  the  process,  by  which  the  carbonic  acid  is  formed,  was  allowed  to  the  previous- 
ly received  opinion  :  however,  it  still  appears  a  matter  of  doubt  how  far  either  function 
predominates ;  tor  we  are  inclined  to  think  that  both  operations  go  on  simultaneously, 
and  that,  whilst  a  portion  of  the  carbonic  acid  gas  is  given  out  from  the,  blood,  already 
formed,  it  is  accompanied  with  another  portion  of  free  carbon,  or  an  oxide  of  carbon, 
or  even  with  an  hydrate  ot  the  same  sui -stance  which  combines  with  an  additional  quan- 
tity of  oxygen  in  the  lungs,  and  thus  forms  the  whole  of  the  carbonic  acid  in  question  ; 
and  that,  at  the  same  time,  a  portion  of  oxygen  is  absorbed,  which  combines  with  the 
carbon  of  the  blood,  and  there  generates  the  carbonic  acid  gas,  or  the  oxide  of  carbon, 
which  forms  a  part  of  the  matters  discharged  from  the  blood  in  the  lungs.  These  pro- 
cesses may  vary,  and  either  may  predominate  according  to  the  state  of  the  vital 
influence  at  the  time,  under  whose  control  they  are  immediately  and  completely  placed. 

This  view  of  the  phenomenon  in  question  seems  to  be  fully  supported  by  the  experi- 
ments of  Dr.  Edwards  of  Paris.  They  prove  that  the  carbonic  acid  gas  does  not  form 

G 


50  APPENDIX, 

instantaneously  io  the  lung's  through  the  action  of  the  respired  au>,  but  that  it  appeals 
be  secerted  to  a  considerable  extent,  from  the  blood  in  the  respiratory  organs. 

As  to  the  quantity  of  this  gas  which  is  formed  during  respiration,  different  physiolo- 
gists have  estimated  it  differently.  Godwin  considered  that  for  every  100  cubic  inches 
of  atmosphere  respired,  there  were  given  off  10  or  11  of  carbonic  acid.  Menzies,  from 
experimentsmade  with  much  accuracy,  found  the  quantity  of  carbonic  acid  to  be  about 
5  in  the  100.  Dr.  Murray  considered  it  to  vary  from  6  to  6.5.  Sir  H.  Davy  from  3.95 
to  4.5.  Messrs.  Allan  and  Pepys  from  5.5  to  9.5,  They  estimated  the  mean  at  about  8. 
Dr.  Prout  found  it  to  be  about  3.45.  Dr.  Fyi'e  about  8.5.  The  discrepancies  which  are 
remarkable  in  these  results  of  the  experiments  performed  by  these  physiologists  doubt- 
less arose,  in  a  great  measure,  from  the  different  proportions  of  this  gas,  produced  by 
different  individuals  according  to  the  state  and  developement  of  the  lungs,  and  accord- 
ing to  the  particular  circumstances  of  the  individual  at  the  time  of  the  experiment. 

The  influence  which  the  state  of  the  individual  exerts  upon  the  function  was  first 
shown  by  the  experiments  of  Dr.  Prout  and  Dr.  Fyfe.  They  proved  that  the  carbonic 
acid  gas  formed  during  respiration  is  liable  to  be  very  materially  affected  in  its  quantity 
in  the  same  individual,  by  various  circumstances.  It  was  formed  in  a  minimum  quanti- 
ty during  the  night ;  and  the  maximum  quantity,  which  was  generally  produced  about 
noon,  exceeded  the  minimum  about  one-fifth  of  the  whole.  The  passions  of  the  mind 
were  found  to  have  a  great  influence  over  its  production  ;  the  depressing  passions  di- 
minishing its  quantity,  and  those  of  an  opposite  nature  the  reverse  ;  exercise,  when  mo- 
derate, appeared  to  increase  in  some  measure  the  quantity,  but  fatigue  diminished  it. 
The  greatest  decrease  experienced  was  from  the  use  of  alcohol  and  vinous  liquors,  es- 
pecially when  they  were  taken  upon  an  empty  stomach.  In  short,  whatever  diminished 
the  powers  of  life,  as  lo\v  diet,  mercurial  irritation,  &c.  appeared  from  the  experiments 
of  Dr.  Prout  and  Dr.  Fyfe  to  have  the  effect  of  diminishing  the  quantity  of  the  carbonic 
acid. 

Dr.  Crawford  found  the  quantity  of  this  gas  was  much  diminished  when  respiration 
\yas  performed  in  a  high  temperature  ;  and  Lavoisier  and  Saguin  confirmed  his  obser- 
vation. Nearly  similar  results  to  theirs  were  obtained  from  some  experiments  which 
we  performed  in  1815  ;  and  from  the  data  thus  obtained  we  endeavoured*  to  account 
for  several  of  the  most  important  diseases  to  which  the  inhabitants  of  warm  countries 
are  liable.  Similar  experiments  were  afterwards  performed  in  an  intertropical  cli- 
mate, where  we  found  the  diminution  of  the  quantity  of  carbonic  acid  to  be  considera- 
bly greater  than  that  which  our  experiments,  in  an  artificial  temperature  of  equal  ele- 
vation had  furnished.  This  seems  to  be  accounted  for  by  the  depressing  influence  upon 
the  nervous  system  which  the  atmosphere,  loaded  with  moisture  and  malaria,  may  be 
reasonably  expected  to  produce.  We  also  attribute  a  share  of  this  discrepancy  to  the 
increased  function  of  the  skin,  which  evidently  co-operates,  in  hot  climates  with  the 
the  lungs,  and  performs  a  subordinate  respiratory  function.  We  shall  not  pursue  this 
particular  topic  farther  at  this  place,  as  we  propose  considering  it  more  at  length  on  a 
Future  occasion. 

Reverting  to  the  question  whether  the  carbonic  acid  is  formed  ivit/iin  the  vessels,  or 
without  them  ;  we  must  remark,  that  the  evidence  on  the  subject  is  very  contradictory. 
The  experiments  of  Dr.  Edwards,  already  referred  to,  show  that  the  former  process  ex- 
ists, at  least  to  some  extent ;  and  it  is  farther  supported  by  the  fact  established  by  Ber- 
zelius,  that  blood,  especially  its  colouring  part,  not  only  absorbs  oxygen  very  quickly, 
but  it  also  retains  some  part' of  the  carbonic  acid  thereby  produced ;  but  whether  or  no 
this  absorption  will  take  place  through  the  parietes  of  the  capillaries,  is  the  point  at  is- 
sue. The  evidence  for  the  absorption  of  oxygen  through  the  capillary  parietes  is,  how- 
ever, nearly  on  a  par  with  that  for  the  excretion  of  the  carbon  ;  if  the  vessels  will  per- 
mit the  transmission  of  the  one,  they  may  allow  the  transit  of  the  other. 

Those  who  contend  for  the  passage  of  the  carbon  from  the  vessels,  and  who,  conse- 
quently consider  thai  the  carbonic  acid  is  formed  externally  as  respects  the  vessels, 
support  their  opinon  by  the  experiments  of  Mr.  Ellis,  who  first  promulgated  the  doc- 
trine. His  experiments,  were,  however,  performed  out  of  the  body,  and  under  cir- 
cumstances which  entirely  excluded  the  operation  of  the  vital  influence  of  the  lungs  and 
of  the  system  generally. 

The  must  conclusive  experiments  in  favour  of  this  opinion  are  those  performed  by 
Messrs.  Magendie  and  Orfila.  They  found  that  phosphorus,  dissolved  in  oil,  and  inject- 
ed into  the  jugular  vein  of  a  dog,  was  expelled  by  the  mouth  and  nostrils  in  the  form 


*  These  views  were  contained  in  a  Latin  Theses  written  at  Edinburgh. 


Of  THE  FUNCTIONS  OF  THE  LUNGS,  51 

6f  copious  vapours  of  phosphorus  acid,  which  could  hardly  have  been  the  case  if  the  phps* 
phorus  acid  had  been  formed  within  the  vessels,  as  in  this  case,  it  would  have  remain- 
ed in  solution  in  the  blood,  it  not  being-  a  volatile  substance.  It  might  therefore  be  sup- 
posed that  the  phosphorus  was  excreted  in  a  state  of  minute  division,  from  the  vessels 
of  the  lungs,  and  meeting,  in  this  state,  with  the  oxygen  of  the  atmosphere,  formed  the 
phosphorus  acid  in  question.  If  this  reasoning  be  admitted  with  respect  to  the  phos- 
phorus, it  may  be  extended  to  the  carbon  contained  in  the  venous  blood. 

From  the  contradictory  eridence  on  the  subject ;  from  the  nature  of  that  evidence ; 
from  the  experiments  of  Dr.  Edwards ;  from  various  analogies  that  might  be  adduced, 
could  our  limits  permit,  from  the  conformation  of  the  lungs,  and  the  extent  of  their 
excreting  and  absorbing  functions  as  evinced  by  experiments  ;  and  lastly,  from  the  con- 
sideration that,  although  respiration  takes  place  frequently,  yet  a  very  large  portion  of 
air  remains  for  a  considerable  time  in  the  chest,  thereby  allowing  the  vitality  of  the 
lungs  themselves  to  be  exerted  upon  the  air  received  into  them, — we  conclude  that 
this  organ  may  act  in  both  the  ways  contended  for  ;  and  that,  whether  it  act  in  one 
manner  or  the  other,  more  or  less  partially,  the  process  is  a  vital  one,  and  whatever 
chemical  laws  may  be  employed  in  it,  are  under  the  control  of  the  vital  influence  of 
the  organ,  and  modified  by  the  ever-varying  condition  of  this  influence. 


n.  Of  Absorption  and  Exhalation  of  Jlzote  during  Respiration. — Another  subject  of 
much  interest  connected  with  the  respiratory  function,  is  that  which  immediately  relates 
to  the  absorption  in  the  lungs  of  a  portion  of  the  azote  contained  in  the  respired  air. 
On  this  point  also,  the  results  of  experiments  have  been  various,  and  opinions  respect- 
ing them  equally  so.  Dr.  Edwards  of  Paris,  who  is  well  known  as  a  very  intelligent 
physiologist,  concludes,  from  different  experiments,  and  from  the  circumstance  of  the 
opposite  results  which  they  give,  some  indicating  a  diminution  of  the  azote  of  the  air, 
others  an  increase  of  it  during  respiration,  that  this  gas  is  absorbed  into  the  circulation, 
and  at ter\vards  discharged  from  it ;  and  that  each  of  these  actions  is  regulated  by  the 
constitution,  habit,  and  circumstances  of  the  individual,  and  by  the  influence  to  which 
he  may  be  subjected,  the  absorption  being  to  a  small  extent,  while  the  exhalation  is 
considerable,  and  vice  versa. 

Independently  of  the  satisfactory  nature  of  the  experiments  whence  Dr.  Edwards 
has  drawn  his  inferences,  there  are  many  collateral  proofs  that  may  be  brought  to  their 
support,  derived  from  the  manifestations  of  the  animal  economy  in  health  and  disease  ; 
and  we  have  little  doubt  that  not  only  in  azote,  but  that  other  gases,  even  those  whose 
presence  in  the  respired  air  are  accidental,  may  be  also  absorbed  into,  and  discharged 
from  the  circulation,  in  a  greater  or  less  quantity,  according  to  the  varying  state  or  the 
vital  energies  of  the  system. 


III.  Of  the  Jlssintildling  Function  of  the  Lungs. — The  extent  of  the  function  of  the 
lungs  has  been  a  matter  of  doubt.  Their  principal  office,  namely,  that  of  changing 
venous  into  arterial  blood,  has  always  been  admitted,  although  the  nature  of  the  pro- 
cess has  been  disputed.  Many  physiologists,  have  in  addition  to  this,  attributed  to 
them  an  assimilating  influence  which  is  exerted  chiefly  upon  the  absorbed  chyle  and 
lymph  which  the  venous  blood  contains.  This  opinion  appears  correct.  But  the  pro- 
cess is  purely  a  vital  one.  If  the  opinion  of  Dr.  Edwards,  respecting  the  absorption 
and  exhalation  of  azote  be  correct,  this  substance  may  be  instrumental  in  the  process. 

A  third  function  has  been  referred  to  this  organ,  viz.  the  formation  of  animal  heat. 
But  however  intimately  related  it  may  be  with  the  respiratory  process,  it  cannot  be 
considered  a  function  of  the  lungs.  It  must,  nevertheless,  be  allowed  that  the  changes 
induced  upon  the  blood  during  respiration,  are  preparatory  to  the  evolution  of  animal 
heat ;  and,  although  we  contend  that  this  heat  is  immediately  the  result  of  a  manifesta- 
tion of  the  vital  influence  of  the  ganglial  system  of  nerves,  exerted  upon  the  blood 
contained  in  the  vessels  to  which  these  nerves  are  distributed,  yet  it  must  be  admitted, 
that  the  respraitory  processes  are  requisite  to  its  production,  inasmuch  as  they  produce 
on  the  blood  a  change  of  properties  which  are  requisite  to  excite  this  system,  and  as 
this  fluid,  when  thus  changed,  contains  the  materials  necessary  to,  or  is  otherwise  in  a 
suitable  condition  for,  the  manifestation  of  the  influence  which  the  part  of  this  system 
of  nerves  which  is  distributed  to  the  blood-vessels  exert. 


52  APPENDIX. 

IV.  Of  Pulmonary  Transpiration. — The  mucus  membrane  of  the  lungs  gives  oft'  a 
considerable  portion  of  the  watery  secretion,  which  is  carried  out  of  the  lungs,  in  the 
form  of  vapour,  by  the  respired  air.  This  perspiration  equally  takes  place  when  the 
animal  breathes  a  gas  containing  neither  oxygen,  hydrogen,  nor  azote  ;  it,  therefore, 
does  not  result  from  the  combining  in  the  lungs  of  the  hydrogen  contained  in  the 
blood  with  the  respired  air,  but  is  strictly  an  aqueous  vapour  slightly  charged  with  ani- 
mal matter — and  is  the  production  of  a  vital  transpiration  or  secretion. 

It  has  not  been  determined  whether  or  no  it  be  produced  from  the  bronchial,  or  from 
the  pulmonary  arteries.  The  question  is  difficult  to  decide,  as  an  injection  thrown  in- 
to either  set  of  arteries  arrives  on  the  surface  of  the  air-cells.  Pulmonary  transpiration 
may  contain,  like  secretions,  foreign  matters  which  have  been  conveyed  into  the  circu- 
lation ;  the  lungs  acting  as  an  organ  eliminating  them  from  the  system.  This  has  been 
shown  by  some  experiments  of  Magendie,  and  also  in  an  experiment  which  we  per- 
formed, in  which  ten  drachms  of  the  oil  of  turpentine  were  chiefly  discharged  by  the 
lungs,  from  the  circulation  in  the  state  of  vapour,  within  twenty-four  hours.  The 
large  quantity  of  the  turpentine  vapour  evolved  from  the  lungs  on  that  occasion,  leads 
us  to  suppose  that  transpiration  takes  place  principally  from  the  venous  blood  about 
the  time  when  the  changes  are  affected  in  it  by  respiration.  This  experiment,  alst* 
seems  to  support  the  doctrine  of  the  evolution  of  carbon  from  the  blood. 


Of  the  Production  of  Jlnimal  Heat. 

4 

Note  Y. 

It  ia  not  necessary  to  add  at  this  place,  much  to  what  is  contained  in  the  text.  We 
then  attributed  the  production  of  animal  heat  to  the  vital  influence  exerted  by  that 
part  of  the  ganglial  system  distributed  to  the  arteries  on  the  blood  which  they  circu- 
late. 

Preparatory  changes,  however,  take  place  in  the  lungs  which  are  necessary  to  the 
exertion  of  this  influence,  and  to  the  evolution  of  heat ;  but  as  it  was  contended  tkat 
those  changes  are  more  of  a  vital  than  of  a  chemical  nature,  so  it  is  considered,  that  the 
production  of  heat  is  more  the  result  of  the  influence  which  the  nerves  of  the  vessels 
exert  upon  the  blood  than  of  the  change  in  the  capacity  for  caloric  which  the  blood 
itself  experiences  in  its  passage  into  the  venous  state.  The  difference  of  capacity 
which  actually  exists  between  venous  and  arterial  blood  is  not  sufficient,  according  to 
the  experiments  of  Dr.  Davy,  to  form  the  basis  of  the  chemical  theory  formerly  re- 
ceived, but  the  difference  which  actually  does  exist  may  be  concerned  in  a  subordinate 
manner  in  the  process. 

Conformably  with  the  opinion,  as  was  first  maintained  on  an  occasion  already  allu- 
ded to,  we  infer  that  the  various  causes  which  modify  the  production  of  animal  heat, 
act,  1st.  immediately  upon  the  organic  system  of  nerves  themselves,  changing  the  con- 
dition of  their  influence  ;  2d,  upon  the  blood,  altering  the  nature  and  composition  of 
this  fluid,  and  thereby  rendering  it  unfit  for  producing  the  requisite  excitement  of  this 
system  of  nerves,  and  incapable  of  the  changes  which  the  influence  of  these  nerves 
produces  upon  its  constituent  parts ,  3d,  immediately  through  the  cerebro-spinal  sys- 
tem, modifying  the  influence  which  this  system  imparts  to  the  ganglial. 

These  different  ways  in  which  the  vital  influence,  exerted  by  this  system  of  nerves 
in  the  production  of  animal  heat,  is  modified,  might  have  been  illustrated  by  experi- 
ments, and  by  reference  to  facts  in  comparative  physiology  and  in  pathology,  if  our 
limits  could  have  admitted  of  so  great  an  extension  of  them.  From  what  we  have  said 
it  will  be  perceived,  that  we  view  the  production  of  animal  heat  more  in  the  light  of  a 
vital  secretion  than  of  a  chemical  phenomenon ;  and  that,  like  the  other  secretions  and 
nutrition,  it  proceeds  from  and  is  controlled  by  the  vital  influence  of  the  ganglial  sys- 
tem of  nerves. 


OF  THE  CUTANEOUS  FUNCTION.  53 

Of  the  Cutane&ua  Function. 
Note  Z. 

I.  Cutaneous  Exhalation,  or  Insensible  Transpiration. — In  transpiration  there  appears 
to  be  two  actions,  a  physical  one  consisting  of  the  evaporation  in  the  air  of  the  fluid 
parts  of  the  body ;  and  a  vital  action,  giving  rise  to  an  excrenientitial  exhalation,  of 
which  the  skin  is  the  organ.  This  view  of  the  subject  is  much  contended  for  by  DP. 
Edwards ;  but  we  think  he  has  refined  in  an  unnecessary  manner  in  explaining  it.  The 
cutaneous  exhalation  is  doubtless  an  organic  function  of  which  the  skin  is  the  organ : 
but,  we  conceive,  that  the  skin  must  first  perform  its  office  before  the  physical  action 
can  take  place  to  any  considerable  extent ;  in  short,  that  as  transpiration  is  pel-formed, 
the  physical  law  operates,  and  that  both  go  on,  the  latter  as  a  consequence  of  the  for- 
mer, pari  passu,  until  an  increase  of  the  transpiration  on  the  one  hand,  and  an  uncom- 
monly dry  state  of  the  atmosphere,  on  the  other,  give  us  different  results.  When  tiie 
former  takes  place  we  perceive  the  formation  of  sweat,  or  the  transpiration  becomes 
sensible  :  when  the  latter  exists,  then  the  phenomenon,  for  which  Dr.  Edwards  and 
some  others  have  argued,  as  constituting  one  of  the  actions  into  which  this  function 
may  be  divided,  really  supervenes  to  some  extent.  Thus  we  have  witnessed,  during 
the  Harmattan  wind,  which  occasionally  blows  on  the  West  coast  of  Africa,  and  which 
is  remarkable  fov  its  dry  ness,  evaporation  going  on  so  rapidly  as  to  give  rise  to  very 
inconvenient  sensations,  and  even  to  serious  disorders  of  the  pai'ts  which  are  usually 
exposed  to  the  air.  In  this  case  the  evaporation  exceeds  the  mere  solution  of  the 
transpired  fluid  in  the  surrounding  atmosphere;  and  the  parts  of  the  body  which  are 
subjected  to  its  operation,  have  a  portion  of  the  fluids  sent  to  the  surface  carried  off 
by  it,  in  addition  to  what  is  exhaled  by  the  natural  and  organic  action  of  the  vessels  of 
the  skin. 

The  cutaneous  exhalation  contains  a  portion  of  the  carbonic  and  lactic  acids. 


II.  Of  the  Sweat  or  Sensible  Exhalation — When  we  said,  if  the  production  of  the  ha- 
litus  or  insensible  transpiration  from  the  skin  exceed  the  evaporation  of  it  in  the  atmos- 
phere, sweat  is  formed,  we  stated  the  source  of  this  fluid.  It  is,  therefore,  produced  the 
from  same  vessels  as  the  insensible  perspiration-  But  although  this  is  the  case,  with  re- 
spect to  their  source,  there  is  some  difference  between  the  nature  or  chemical  constitu- 
tion of  the  sensible  and  insensible  cutaneous  exhalations.  The  former  is  generally  less 
charged  with  carbonic  acid  than  the  former,  but  it  abounds  more  with  the  salts  usually 
excreted  from  the  system. 

A  careful  view  of  the  functions  of  the  skin  throughout  the  different  classes  of  animals, 
leads  us  to  conclude  that  it  performs  operations  which  hold  an  intermediate  place  be- 
tween those  of  respiration  and  elimination, — that  it  partakes  of  the  character  of  a  respi- 
ratory and  of  an  eliminating  organ. 

1.  It  is  a  Respiratory  Organ — This  is  shown  by  the  circumstance  of  this  function  be- 
ing performed  in  the  lower  order  of  animals  by  the  surface  only;  and  by  the  gradation 
observed  from  these  up  to  the  higher  orders,  and  by  the  gradual  perfection  at  which 
the  respiratory  organ  arrives  in  ascending  the  scale  of  animal  creation.  In  the 
higher  animals  the  respiratory  apparatus  becomes  more  and  more  distinct,  and  the  func- 
tion depending  upon  it  more  and  more  limited  to  appropriate  organs;  however,  the 
same  type  which  characterizes  the  lower  orders,  and  is  most  remarkable  in  them,  is  still 
preserved  throughout  the  whole  series  of  the  animal  scale,  although  it  becomes  gradu- 
ally, and  nearly,  but  not  altogether  lost.  Thus  in  man,  the  lungs  perform  the  chief  re- 
spiratory process  ;  but,  even  in  him,  the  respiratory  function  of  the  skin  is  remarkable, 
Carbonic  acid  gas  is  produced  from  the  cutaneous  surface,  transpiration  also  takes  place 
there  ;  and  this  respiratory  act  of  the  skin  becomes  more  or  more  remarkable  under 
circumstances  which  diminish  or  partially  obstruct  the  respirator}'  process  of  the  lungs. 
Thus  we  found  that  the  quantity  of  carbonic  acid  gas,  formed  in  the  lungs  in  a  given  time 
and  in  the  same  individual,  was  about  one-third  less  in  a  hot  climate  than  in  a  cold  one  ; 
this  was  about  the  average  result  of  our  experiments:  whilst  we  observed  that  the  respira- 
tory function  of  the  skin,  both  as  respects  the  quantity  of  the  insensible  transpiration  and 


54  APPENDIX. 

the  formation  of  carbonic  gas,  was  very  remarkably  increased.*  In  a  Negro,  as  far  as  we 
could  infer  from  experiments  performed  on  a  single  limb,  the  respiratory  function  of 
the  external  surface  of  the  body  was  much  greater,  and  the  quantity  of  carbonic  acid 
formed  in  his  lungs  much  less  than  in  our  own  case  although  our  size  and  weight  were 
equal.  Hence  we  were  led  to  infer  that,  in  this  race  of  the  human  species,  the  skin 
performs  a  much  greater  supplementary  function  to  that  of  the  lungs,  than  in  the  in- 
habitants of  cold  or  temperate  climates. 

In  two  cases  which  came  under  our  observation,  in  which  the  lungs  were  partly  de- 
stroyed from  an  imposthume,  and  the  side  of  the  chest  was  consequently  contracted, 
the  cutaneous  functions  were  afterwards  very  remarkably  increased.  Were  it  consist- 
ent with  the  limits  of  these  notes,  many  facts  illustrative  of  this  particular  function  of 
the  skin,  as  it  respects  the  inhabitants  of  cold,  temperate,  and  hot  climates,  might  be 
adduced. 

2.  The  Skin  is  an  Eliminating  Organ. — Richerand'  has  so  fully  illustrated  this  func- 
tion of  the  skin,  and  contrasted  it  with  that  performed  by  the  kidnies,  that  it  is  unneces- 
sary to  say  any  thing  respecting  it,  at  this  place.  The  chemical  analysis  of  the  perspir- 
ed fluid,  given  in  the  next  chapter  of  the  Appendix,  will  show  to  what  extent  it  pep- 
forms  an  eliminating  office. 


Of  tte  Fluid? 
Note  AA. 

In  .addition  to  the  classifications  of  the  fluids,  we  may  mention  that  adopted  by  M. 
Chaussier.  He  divides  the  fluids  into  five  classes  :  those  produced  by  the  digestive 
process — the  chyme  and  the  chyle;  the  circulating  fluids — the  lymph  and  the  blood; 
the  exhaled  or  perspired  humours;  the  follicular  humours,  and  the  glandular  hu- 
mours. 

M.  Adelon,  the  able  and  eminent  pupil  of  M.  Chaussier,  has  proposed  another  classi- 
fication, which  possesses  some  advantages  over  those  which  have  preceded  it.  It  is 
also  simpler  and  more  natural.  He  divides  the  organic  fluids  into  those  of  Maorgtion, 
the  fluid  especially  Nutritive,  and  the  Secreted  Humours. 

1°  The  Absorbed  Fluids  are  the  chyle,  the  lymph,  and  the  venous  blood.  These  are 
taken  up  and  conveyed  by  the  lymphatic  and  venous  class  of  vessels,  and  ultimately 
become  assimilated  with,  and,  indeed,  concur  to  form  the  fluid  specifically  nutritive. 
Thus  the  chyle,  after  a  longer  or  shorter  course,  mingles  with  the  lymph,  both  are 
poured  into  the  venous  blood,  and  when  they  arive  at  the  organs  of  respiration,  they 
become  perfectly  united,  being  converted  into  the  nutritive  fluid  by  the  functions  of 
those  organs. 

2°  The  Fluid  especially  Nutritive.-— The  three  fluids  constituting  the  first  class  being 
changed  in  the  respiratory  organs  into  that  which  can  alone  nourish  the  body,  thus 
constitute  the  second  class,  which  in  its  turn,  furnishes  the  materials  of  all  those  em- 
braced by  the  third.  The  second  class  is,  therefore,  the  arterial  blood  only,  which  be- 
ing fully  perfected  in  the  lungs  by  the  action  of  the  atmospheric  air,  and  circulated 
throughout  the  body,  furnishes  the  materials  of  nutrition  and  secretion,  and  stimulates, 
and  contributes  to  preserve  the  functions  of  the  living  solids,  and  in  conjuncton  with 
these  solids,f  produces  the  calorification  of  the  animal  system. 

3°  The  Secreted  Humours — This  class  may  be  divided  into  three  orders,  according  to 
the  forms  of  the  secreting  organs  which  produce  them  ;  namely,  into  Exhaled  or  Per- 
spired Fluids,  Follicular  Humours,  and  Glandular  Humours. 

Jl.  Exhaled  or  Perspired  Humours. — These  are  numerous,  are  produced  in  the  form 
of  vapour,  and  they  differ  from  one  another  in  their  physical  and  chemical  properties, 
and  in  the  purposes  which  they  fulfil  in  the  animal  economy.  They  are,  moreover,  dis- 


*  The  experiments  whidi  were  made  in  order  to  ascertain  this  from  the  want  of  the 
means  and  proper  facilities  were  not  performed  upon  the  whole  body,  they  were  made 
only  upon  a  single  limb ;  but  the  results  were  very  decisive  and  remarkable. 

f  By  living  solids  is  here  meant  all  sensitive  and  irritable  parts — all  those  which  are 
influenced  by  an  irritating  cause. 


CLASSIFICATION  OP  THE  TLUID9.  55 

linguished  into  those  which  are  taken  up  by  lymphatic  or  venous  absorption,  and  carri- 
ed back  into  the  torrent  of  the  circulation,  and  into  these  which  are  entirely  thrown  out 
of  the  body  ;  the  former  being  usually  denominated  recrementitial,  the  latter  excrementi- 
tial, from  these  circumstances. 

The  recrementitial  fluids  are  all  produced  in  cavities  or  in  situations  that  have  no  ex- 
ternal outlet.  The  following  enumeration  includes  all  the  fluids  appertaining  to  this 
genus  :— 1°  Serona  fluids,  as  those  which  are  exhaled  on  the  surface  of  the  arachnoid, 
of  the  pleura,  of  the  pericardium,  the  peritoneum  and  the  tunica  vagmalis.—  2°  Tho 
Synovia.  3°  The  ncrosity  of  luminous  tissues.— ±°  The/a*  formed  in  the  adipose  tissue. 
—5°  The  marrow,  or  medullary  juice.— 6Q  The  colouring  humour  of  the  skin,  placed  un- 
der the  epidermis.—  7°  The  colouring  humours  of  the  ins,  of  the  uvea,  and  of  the  cho- 
roid.— 8°  The  three  humours  of  the  eve— the  aqueous,  crystalline,  and  vitreous — 9°  The 
Ivmph  of  Cotug?io.—lQ°  The  fnanmtr  of  the  lymphatic  glands,  a  gelatmo.albuminous  fluid, 
existing  in  the  spongy  tissue  of  their  organs.— 11°  and  lastly,  the  fluid  perspired  on  the 
internal  surface  of  all  the  vessels,  the  existence  of  which  may  be  doubted,  as  it  is  next 
to  impossible  to  demonstrate  its  existence.  In  addition  to  the  perspired  recrementitial 
fluids  may  be  added  those  which  exist  in  the  human  ovum,  viz.  the  amniotic  fluid  ;  the 
-water  of  the  chorion,  which  exists  between  thechorion  and  amnios,  only  during  the  early 
months  of  pregnancy ;  and  the  -water  of  the  umbilical  vesicle,  which  may  be  compared  to 
the  yolk  of  an  egg,  and  which  some  physiologists  believe  destined  to  nourish  the  em- 
bryo before  the  developement  of  the  placenta. 

The  excrementitial  perspired  fluids  are  all  thrown  otf'  from  the  external  surface  of 
the  body,  and  from  the  mucous  membranes  which  have  a  communication  externally  by 
means  of  the  natural  outlets,  and  which  may  therefore  be  considered  as  merely  form- 
ing  parts  of  the  external  surface.— lc  Those  fluids -which  perspire  from  theski.n,  as  the  cu- 
taneous insensible  perspiration,  and  the  humour  constituting  the  sweat— 2°  The  fluids 
per  spired  from  the  respiratory  apparatus  ;  these  differ  somewhat  in  different  situations,  as 
in  the  nasal  cavities,  in  the  trachea,  and  bronchia- — 3Q  The  humours  exhaled  on  the  sur- 
face of  the  digestive  canal. — 4°  Those  humours  exhaled  on  the  internal  surface  of  the  uri- 
nary apparatus,  viz.  on  the  internal  surface  of  the  ureteis,  the  bladder,  and  urethra. — 
5°  The  fluids  exhaled  from  the  genital  organs,  namely  from  the  internal  surface  of  the 
vesiculx  seminales  and  ejaculatory  conduits,  in  the  male,  and  from  the  nterus  and  va- 
gina in  females  (the  menstrual  flux  and  the  lochise.) 

B.  The  Secreted  FoUicular  Fluids  are  those  formed  by  a  particular  secreting  organ 
called  follicular.  They  are  all  excrementitial,  and  consequently  are  formed  on,  and 
eliminated  from,  the  two  external  suifaces  of  the  body — the  skin  and  mucous  mem- 
branes. They  consist  of — 1°.  The  sebaceous  humour  of  the  skin. — 2°  The  cerumen  ; 
the  humours  of  Meibomius. — 3°  The  humour  of  the  caruncula  lachrymalis. — 4°  The  hu- 
mour secreted  at  the  base  of  the  glans  penis  in  the  male,  and  on  the  surface  of  the 
vulva  in  the  female.  The  humours  secreted  by  the  follicles  in  the  mucous  surfaces  are 
generally  characterized  by  the  generic  term  mucous.  They  are  distinguished  into  the 
mucus  of  the  respiratory  organs,  the  mucous  of  the  digestive  apparatus,  of  the  urinary  ap- 
paratus, and  of  the  genital  organs.  The  humours  formed  by  the  prostate,  and  by  the 
glands  of  Co-wper — compound  and  glandiform  follicles — are  usually  referred  to  the  last 
mentioned  in  this  enumeration.  The  fluid  secreted  by  the  tonsils  is  generally  classed 
\vith  those  of  the  digestive  organs. 

C.  Lastly.  The  Secreted  Glandular  Humours  are  the  production  of  glandular  organs. 
They  are — 1°  The  lachrymal  fluid. — 2Q  The  salivary  fluid. — 3°  The  pancreatic  AM- 
mours.— 4°  The  bile. — 5°  The  urine — 6°  The  semen  /  and  7Q  the  milk. 

It  may  be  remarked  generally  with  respect  to  the  humours,  that  the  degrees  of  fluid- 
ity which  belonging  to  them,  vary  greatly  from  a  state  of  gas  or  of  vapour,  to  that  of 
semi-fluidity : — they  have,  moreover,  all  the  physical  conditions  constituting  a  fluid 
body.  Their  fluidity,  however,  does  not  result  from  the  general  forces  of  matter,  but 
from  those  of  life.  Indeed  the  vital  influence  modifies  their  physical  form  of  existence, 
in  a  more  or  less  marked  manner,  as  long  as  they  continue  subjected  to  its  operation. 
Prom  this  source  also  they  are  imbued  with  a  certain  influence,  the  presence  of  which 
indicated  by  the  continuance,  for  a  time,  of  the  specific  characters  of  each.  This  in- 
fluence, being  no  longer,  renewed  when  they  are  removed  from  the  body,  soon  be- 
comes dissipated,  and  the  secretion  which,  while  within  the  sphere  of  the  animal  sys- 
tem and  for  a  short  time  afterwards,  possessed  an  emanation  of  the  vital  influence  suffi- 
cient to  give  it  certain  characters,  and  to  preserve  it  from  the  chemical  changes  to 
which  its  constituents  are  naturally  prone,  at  last  falls  into  a  state  of  dissolution,  as  u  ic- 
quivocal  as  that  evinced  by  the  te'xtures  of  the  body.  In  confirmation  of  this  view,  we 
need  only  refer  the  Physiologist  and  Pathologist  to  the  comparative  condition  of  the 
more  perfectly  elaborated  secretions  immediately  after  their  formation  and  excretion. 


55  .APPENDIX. 

and  after  periods  of  various  duration  have  elapsed  from  the  time  of  their  discharge  from 
the  body. 

Finally,  we  may  remark  that  the  fluids,  being  composed  of  molecules  moving  with 
facility  on  each  other,  cannot,  as  the  solids,  be  traced  to  constituents  of  an  elementary 
nature.  They  can  only  become  the  subject  of  microscopic  research  in  our  endeavours 
to  trace  the  nature  of  their  constitution  :  by  this  means  we  can  merely  learn  that  they 
are  generally  composed  of  globules,  swimming  in  a  fluid  substance,  and  whatever  be 
the  fluid  employed,  we  perceive  only  globules  suspended  in  an  amorphous  liquid.  It 
should,  however,  be  remarked  that,  as  we  find  in  some  solids  merely  a  concreted  amor- 
phous substance  containing  no  globules,  as  in  the  cellular  tissue  for  example,  so  we 
perceive  some  fluids  destitute  of  globules  and  formed  only  of  an  amorphous  substance, 
which  is  perfectly  fluid.  In  other  solids  and  fluids,  on  the  contrary,  we  h'nd  both  glo- 
bules and  an  amorphous  matter,  which  is  concrete  in  the  former  and  liquid  in  the  other. 
But  these  globules  vary  greatly,  both  in  solids  and  in  fluids,  and  even  in  the  same  part, 
according  to  age  ;  those  of  the  blood,  for  instance,  are  composed  ci  a  solid  central  part, 
and  of  an  external  envelope  which  is  coloured;  those  of  the  chyle  appear  to  be  the 
same  as  the  central  part  of  the  former  without  its  coloured  envelope ;  those  of  the  mus- 
cular fibre  seem  to  be  the  same  as  those  of  the  blood ;  those  of  the  brain  and  nerves  are 
smaller  than  the  foregoing ;  and  those  of  the  kidneys  are  smaller  than  those  of  the 
spleen. — During  the  first  epoch  of  conception  the  globules  are  not  visible ;  they,  how- 
ever, soon  form,  and  become  more  and  more  distinct.  See  on  this  subject  Physiologic 
de  I'Homm*,  par-JV.  P.  ^Idelon.  Vol.  1.  p.  116. 


Of  the  Blood. 
Note  BB. 

I.  Of  the  fimgtt  colourless  Globules  of  the  Hlood.^-The  researches  of  Sir  Everard  Home, 
and  Mr.  Bauer,  (Phil.  Trans,  for  1820,)  seem  to  lead  to  the  following  conclusions  re- 
specting these  globules. 

1.  That  the  milk-like  fluid,  the  produce  of  digestion  (cliyle)  which  is  found  in  the 
lacteal  vessels  and  glands,  contain  an  infinite  number  of  white  globules,  chiefly  of  a 
minute  size. 

2.  These  newly  discovered  minute  globules  are  __ *      part  of  an  inch  in  diameter. 

3.  That  the  chyle  contains  also  some  white  globules  of  the  size  of  the  red  globules  of 
the  blood. 

3.  Mr.  Bauer  supposes  that  the  full  sized  globules  acquire  their  form  in  the  lacteal 
glands. 

5.  Sir  Everard  Home  considers  that  the  globules  of  the  blood  receive  their  red  hue 
in  the  vessels  of  the  lungs. 

6.  That  lymph  or  fibrine,  whether  taken  from  an  inflamed  surface,  from  the  buff  of 
\vhat  is  commonly  called  inflamed  blood,  or  from  the  slowly  formed  layers  of  aneuris- 
mal  tumours,  consists  of  innumerable  white  globules,   much  smaller  than  those  which 
constitute  the  red  globules  of  the  blood,  and  similar  to  those  minute  globules  already 
described. 

7.  That  these  small  globules  constitute  the  substance  thrown  out  in  inflammation. 

8.  That  they  are  held  in  solution  in  the  st  rum,  and  consequently  are  only  brought 
into  view  in  the  act  of  coagulation. 

9.  That  these  globules,  as  well  as  those  which  subsequently  receive  the  red  colour, 
are  the  produce  of  digestion,  and  are  formed  in  the  pyloric  portion  of  the  stomach,  and 
in  the  duodenum,  surrounded  by  a  glairy  mucous,  which  is  met  with  in  these  parts. 

M.  Prevost  and  Durnas*  agree  with  Sir  Ev.  rard  Home,  as  to  the  form  and  structure  of 


*  The  microscopic  observation  of  the  blood  satisfied  these  gentlemen,  that  this  liquid 
during  life,  was  nothing  else  than  the  serum,  holding  in  suspension  small,  regular,  and 
insoluble  corpuscles.  These  are  uniformly  composed  of  a  central  colourless  spheroid, 
and  of  a  species  of  membranous  bag1,  oi'  a  fed  colour,  Surrounding  this  spheroid,  from 
which  it  is  easily  separable  alter  death.  The  central  body  is  white,  transparent,  of  a 
spherical  form  in  animals  with  circular  particles  ;  of  an  ovoid  form,  in  those  with  ellipti- 
cal particles.  Its  diameter  is  constant  in  the  first,  but  it  varies  very  perceptibly  in  the 


OF  THE  COAGULATION  OF  THE  BLOOD.  57 

the  globules  of  the  blood ;  but  they  do  not  admit  with  him  that  the  red  globules  undergo 
a  rapid  change  after  they  escape  from  the  vessels,  or  that  the  colouring  matter  which  en- 
velopes the  central  spherical  body  separates  as  soon  from  the  globule,  as  thirty  seconds 
after  the  blood  has  issued  from  the  vein.  They,  however,  agree  with  him  in  saying, 
that  these  central  spheres  (the  smaller  globules)  unite  themselves  in  filaments,  which 
differ  in  no  respect  from  the  muscular  fibre.  They  observed  also  small  globules  in  the 
milk,  in  pus,  and  in  the  chyle ;  and  they  consider  "that  those  of  the  former  fluids  have 
been,  and  these  of  the  latter  are  to  be,  surrounded  by  the  colouring  matter  of  the 
blood. 

Messrs.  Prevost  and  Dumas  found  the  globules  of  the  blood  to  be  circular  in  all  the 
mammalia  ;  and  in  their  size  to  vary  in  different  animals ;  they  are.  smallest  in  the  goat. 

The  globules  are  elliptical  in  birds,  and  they  vary  considerably  in  size  in  this  class  of 
animals.  This  variation  is  chiefly  in  the  great  axis  of  the  globules.  They  are  ellip- 
tical also  in  all  cold-blooded  animals. 


IF.  Of  the.  Coagulation  of  the  Blood, — On  this  part  of  the  subject  before  us,  we  cannot 
enter  minutely.  We  will  merely  state,  as  briefly  as  we  can,  those  inferences  at  which 
we  have  arrived,  after  a  careful  "examination  of  the  phenomenon  itself,  under  various 
circumstances,  and  of  the  different  opinions  entertained  respecting  it. 

1.  According  to  the  observations  of  Treviranus  and  Kolk,  whose  observations  on  this 
subject  have  been  extended  and  faithful,  the  particles  or  globules  of  the  blood  possess 
a  rotatory  motion  during  life,  and  this  motion  continues  until  the  phenomenon  of  coa- 
gulation takes  place. 

2.  That  this  motion  of  the  globules  is  the  cause  of  the  blood's  fluidity. 

3.  That  the  motion  of  the  globules  is  the  consequence  of  the  vital  influence  emanat- 
ing from  the  glanglial  nerves  distributed  in  the  parietesof  the  vessels  in  which  they  cir- 
culate. 

4.  That  the  cause  of  the  coagulation  of  the  blood  is  not  to  be  found  in  external  agen- 
cies but  in  the  loss  of  that  emanation,  (proceeding  from  the  organic  nerves  distributed 
to  the  coats  of  the  vessels,)  of  the  vital  influence  with  which  the  globules  are   en- 
dowed. 

5.  That  the  presence  of  the  air,  especially  of  the  oxygenous  portion  of  it,  promotes 
this  phenomenon. 

6.  That  when  coagulation  commences  at  any  point  of  a  mass  of  blood  it  is  rapidly 
propagated  throughout  the  whole  ;  this  may  arise  from  the  cause  being  co-ordinate,  or 
nearly  so,  throughout  the  whole. 


second.     It  manifests  also  a  great  disposition  to  form  aggregates  or  ranges,  in  the  form 
of  a  string  of  beads. 

The  coloured  portion  appears  to  be  a  kind  of  jelly,  easily  divisible,  but  insoluble  in 
water,  from  which  it  may  always  be  separated  by  repose/  It  is  likewise  transparent, 
but  much  less  so  than  the  central  corpuscle  ;  and  the  fragments  arising  from  its  division 
are  not  susceptible  of  regular  aggregation.  As  the  attraction,  which  keeps  the  red 
substance  fixed  round  the  white  globules,  ceases  at  the  same  time  with  the  movement 
of  the  liquid,  these  globules  can  then  obey  the  force  whvh  tends  to  unite  them,  and  to 
form  a  net-work,  in  whose  meshes  the  liberated  red  colouring  matter  gets  enclosed  ; 
and  thus  produce  the  phenomenon  of  coagulation.  If  the  eoagultim  be  exposed  to 
a  stream  (jf  water,  the  colouring  matter  is  washed  away,  while  the  aggregate  formed 
by  the  white  globules  remains  in  the  form  of  filaments,  in  which  may  be  recognised,  by 
means  of  the  microscope,  the  aspect  and  structure  of  the  muscular  fibre. 

Three  animal  substances  ought,  therefore,  to  fix  our  attention  :  these  are,  the  albu- 
men of  the  blood,  the  white  globule,  and  the  colouring  matter  which  envelopes  this. 
With  respect  to  the  colouring  particles  of  the  blood,  these  chemists  suppose  that  it. is 
formed  of  an  animal  substance,  in  combination  with  a  peroxide  of  iron.  The  colourless 
globules  they  consider  to  be  coagulated  allnimcn.  They  have  examined  the  proportion 
which  the  white  corpuscles  and  red  matter  together  bear  to  the  rest  of  the  blood,  in  a 
great  variety  of  animals  ;  and  they  find  them  most  abundant  in  birds,  next  in  the  mamma- 
lia, especially  the  carnivorous  mammalia  ;  and  they  are  least  plentiful  in  cold-blooded 
animals.  In  man  they  consftute  about  one  hundred  and  twenty -nine  parts  by  weight, 
per  thousand.  They  are  iiiore  abundant  in  arterial  than  in  venous  blood  ;  one  thousand 
parts  of  the  arterial  blood  of  the  sheep,  dog,  and  cat,  contain  ten  parts  more  of  these 
particles  than  blood  taken  from  the  veins.  The  serum  is  identical  in  both. 

H 


58  APPENDIX. 

7.  Neither  the  heat  of  the  body,  nor  the  strength  of  the  circulation,  are  causes  of  the 
bloods's  fluidity,  they  are  both  results  of  one  cause,  viz.  the  vital  energy  of  the  vessels  ; 
both  are  co-ordinate,  and  both  as  well  as  the  phenomena  of  coagulation  itself,  are  de- 
pendent on  this  one  source. 

8.  That  coagulation  occurs  sooner  in  venous  than  in  arterial  blood,  and  that  coagu- 
lation of  arterial  blood  is  still  longer  delayed  if  it  be  prevented  from  leaving  the  arte* 
lies. 

9.  That  coagulation  takes  place  the  sooner  after  the  blood  is  removed  from  the  vital 
sphere  of  the  s;,  stem,  the  weaker  the  vital  energy  to  which  it  was  subjected  whilst  cir- 
culating in  the  system. 

10.  That  the  weaker  the  vital  energy,  and,  consequently,  the  quicker  the  coagula- 
tion, the  more  lax  is  the  coagulum  which  is  formed. 

11.  That,  on  the  same  principle,  coagulation  is  more  slow,  and  the  coagulum  more 
firm,  according  as  the  vital  influence  of  the  vessels  is  more  energetic. 

12.  That  the  quantity  of  globules  modifies  these  results  ;  a  large  proportion  also  of 
these  globules  indicates  great  energy,  and  vice  versa. 

13.  That  as  the  central  globules  retain  their  coloured  envelopes,  during  their  circula- 
tion in  the  blood-vessels,  and  lose  them  soon  after  removal  beyond  the  sphere  of  the  vi- 
tal influence  of  these  vessels,  and  as  this  is  a  part,  and  indeed  the  first  part  of  the  act  of 
coagulation,  so  we  consider,  that  it  is  in  consequence  of  the  vitality  emanating  from  the 
interior  of  the  vessels  into  the  blood,  that  the  coloured  envelopes  of  the  central  globules 
continue  to  surround  them ;  and,  consequently,  that  the  separation  of  the  envelope 
from  the  central  globule  is  the  result  of  the  loss  of  the  chief  portion  of  that  vitality 
which  proceeds  from  the  containing  blood  vessels  ;  and,  as  this  loss  of  vitality  may  be 
reasonably  supposed  to  be  quickest  where  it  has  been  originally  the  least,  therefore  the 
seperatioii  of  the  envelopes  and  the  coagulation  will  be  the  quicker  the  weaker  the  vi- 
tal energy,  and  vice  versa  ;  and  the  coagulum  will  be  the  more  lax. 

14.  That  the  loss  of  the  vitality,  emanating  from  the  vessels,  and,  consequently,  the 
loss  of  their  envelopes,  disposes  the  central  globules  to  attract  each  other  ;  and  that  in 
the  exertion  of  this  contraction  they  dispose  themselves  into  reticulated  fibres,  which 
entangle  the  colouring  matter  and  a  portion  of  the  serum ;  and  thus  the  clot  is  formed. 

15.  It  would  appear  that  the  central  globules  continue  to  retain,  in  the  fibres  which 
they  form,  in  the  act  of  coagulation,  a  small  portion  of  the  vital  enmaation  with  which 
they  were  endowed  ;  in  as  much  as  the  fibrous  part  of  the  coagulum  evinces  phenome- 
an  approaching  to  those  denominated  irritable ;  and  that  it  is  the  loss  of  the  chief  part  of 
the  vitality,  and  not  the  whole  of  it,  which  occasions  the  separation  of  the  coloured  enve- 
lopes from  the  central  globules. 

16.  That  the  firmness  of  the  coagulumancl  the  irritable  phenomena  e  vinced  by  its 
fibrous  part  are  proportionate  in  degree  to  the  vital  energies  with  which  the  vessels  are 
endowed  by  the  ganglial  nerves  distributed  in  them,  and  to  the  emanation  which  the 
globules  themselves  derive  from  this  source. 

17.  That  the  vital  emanation,  proceeding  from  the  ganglial  nerves  distributed  in  the 
vessels,  affecting  the  globules  in  this  manner,  and  giving  rise  to  these  phenomena,  has 
been  the  cause  of,  and  has  countenanced,  the  hypothesis  of  the  vitality  of  the  blood — 
a  vitality  which  does  not  originally  belong  to  it,  which  it  possesses  in  a  diminished  de- 
gree, and  which  is  an  emanation  from  a  different  source,  which  source  is  efficient  in  the 
formation  of  the  blood  itself,  and  bestows  on  it  through  the  medium  of  the  vessels  con- 
taining it,  the  chief  properties  which  this  fluid  evinces  in  health  and  in  disease. 

18.  That  when  the  vitality  of  the  blood-vessels  is  greatly  diminished,  as  in  purpura 
haemorrhagica,  scurvy,  and  in  other  diseases,  coagulation  either  does  not  at  all  take 
place,  or  it  takes  place  very  quickly  and  the  coagulum  is  weak,  lax,  and  resembling 
cruor.  Under  such  circumstances,  the  envelopes  separate  rapidly  from  the  central  glo- 
bules, because  the  vitality  of  the  vessels  is  scarcely  sufficient  to  continue  them  in  con- 
nexion, even  when  circulating  through  the  vessels  themselves ;  coagulation  takes  place 
quickly,  because  the  motion  impressed  upon  the  globules  by  the  vital  energy  of  the 
vessels,  owing  to  the  defect  of  this  energy,  is  soon  lost,  and  because  the  separation  of 
the  envelopes  from  the  globules  takes  place  almost  instantly  ;  and  the  coagulum  which 
is  formed  is  weak,  or  it  does  not  form  at  all,  because  the  vitality  of  the  globules  is  in- 
sufficient to  dispose  to  an  energetic  attraction,  or  even  to  any  attraction  between  the 
central  globules. 

19.  and  lastly.  Opposite  phenomena  result  from  the  increased  energy  of  the  vital 
functions  of  the  ganglial  nerves  distributed  to  the  blood-vessels. 


OF  SECRETION  AND  EXHALATION.  59 

HI.  Of  Transfusion  of  Blood.-— Messrs.  Prevost  and  Dumas  found  that,  after  bleed! ng 
an  animal  until  all  organic  actions  ceased,  and  injecting-,  within  a  few  minutes  after- 
wards,  the  warm  blood  taken  from  another  of  the  same  species,  until  a  quantity  equal 
to  that  taken  wag  restored,  the  animal  gradually  revived  and  took  nourishment,  and 
entirely  recovered,  if  the  operation  was  perfectly  performed. 

If,  however,  the  blood  injected  was  taken  from  an  animal  of  a  different  species,  pos- 
sessing globules  of  the  same  form,  but  different  in  dimensions,  the  animal  was  very  im- 
perfectly revived,  and  could  be  rarely  preserved  beyond  six  days.  The  pulse  became 
in  these  frequent,  the  temperature  fell  remarkably,  if  not  artificially  preserved,  while 
the  respiration  retained  its  natural  frequency.  Immediately  after  the  operation,  the  de- 
jections became  mucous  and  bloody;  and  preserved  that  character  until  death. 

If  blood  with  circular  globules,  was  injected  into  the  veins  of  a  bird,  the  animal  ge- 
nerally died  before  the  operation  was  completed,  in  very  violent  and  nervous  convul- 
sions. 

Transfusion  of  blood  from  the  cow  or  sheep  into  the  veins  of  the  cat  or  rabbit,  was 
followed  by  the  recovery  of  the  animal  in  a  number  of  cases. 

The  blood  of  the  sheep  excited  in  the  mallard  duct  the  most  violent  and  rapid  con- 
vulsions, which  were  immediately  followed  by  death,  as  was  observed  to  follow  the  in- 
jection of  the  first  syringcful  inland-birds.  (Biblioikeque  Univers.  Juillet,  1821.) 


Of  Secretim  and  Exhalation. 
Note  CC. 

Opinions  have  been  various  respecting  the  mechanism  provided  for  the  performance 
of  exhalation  and  secretion.  One  class  of  physiologists  contends  for  a  separate  order  of 
very  minute  capillaries  proceeding  from  those  carrying  red  blood,  which  they  call  ex- 
halent  or  secretory  capillaries,  and  devoted  to  these  functions.  Belonging  to  this  class 
we  may  reckon  Haller,  Hewson,  Scemmering,  Bichat,  Chaussier,  Alard,  &c.  As  these 
vessels  cannot  be  demonstrated,  there  existence  is  denied  by  Mascagni,  Prochaska, 
Richerand,  Magendie,  and  others,  who  argue,  that  these  functions  take  place  in  the 
sanguineous  capillaries  through  the*  medium  of  organic  lateral  pores.  The  fact  ap- 
pears to  be  that  the  evidence  for  a  separate  set  of  capillaries  is  equal  to  that  for  the  ex- 
istence of  organic  pores  in  the  capillaries  carrying  red  blood  ;  it  is  not  easy  to  demon- 
strate the  presence  of  either;  whilst  both  the  one  and  the  other  may  prove  a  sufficient 
medium  through  which  the  processes  will  go  on  under  the  influence  with  which  the 
capillary  vessels  are  endowed.  The  existence  and  efficacy  of  this  influence  is  sufficiently 
manifest,  although  the  more  minute  intruments  by  means  of  which  it  operates,  can- 
not be  satisfactorily  demonstrated  to  our  senses. 

With  respect  to  secretion,  the  state  of  opinions  and  of  our  knowledge  as  to  the  man- 
ner in  which  it  takes  place,  or  rather  the  mechanism  provided  for  its  performance,  is 
similar  to  what  we  have  shown  to  exist  on  the  subject  of  absorption  and  on  that  of  the, 
minute  capillaries.  In  stating  the  opinions  on  these  subjects,  and  those  lately  espoused 
by  M.  Alard.  we  gave  the  views  of  those  who  contend  for  the  existence  of  minute 
lymphatics  running  into  the  venous  capillaries,  in  a  similar  manner  to  that  in  which  ex- 
halent  vessels  are  supposed,  as  stated  above,  to  proceed  from  the  arterial  capillaries. 
But  the  latter  set  of  vessels  has  been  as  little  seen  as  the  former.  This,  however,  in  a 
matter  of  this  nature,  is  not  a  sufficient  proof  against  their  existence.  Other  physiolo- 
gists, on  the  other  hand,  contend  that  exhalation  and  secretion  take  place  through 
means  of  pores  analogous  to  those  which  are  supposed  to  be  instrumental  in  the  phe- 
nomena of  absorption  ;  and  that  the  process  is  entirely  one  of  transudation.  But  the 
same  objection  may  be  offered  against  the  existence  of  pores  as  to  that  of  the  exhalents 
or  secreting  capillaries  in -question. 

We  believe  that  the  precise  way  in  which  exhalation  and  secretion  take  place  can- 
not be  readily  demonstrated  to  the  senses, — that  the  one  apparatus  may  explain  the 
process  as  well  as  the  other, — that  secretion  as  well  as  absorption,  are  not  mechanical 
processes,  although  there  are  apparatuses,  or  subordinate  instruments,  provided  for 
their  performance,  and  that  they  are  essentially  vital  operations,  and  under  the  control 
of  the  vital  influence  with  which  the  capillaries  themselves,  and  the  organs  to  which 
they  belong,  are  endowed. 

As  to  the  question  of  pores,  it  must  be  granted  that  the  solids  of  the  body,  and  the 


60  APPENDIX, 

parietes  of  the  vessels,  are  all  porous ;  it  is  only  with  respect  to  the  extent  and  mag- 
nitude of  the  pores  that  the  question  can  be  entertained.  Those  who  contend  for  the 
existence  of  separate  and  subordinate  sets  of  capillary  vessels  cannot  deny  the  exis- 
tence of  pores,  for  if  they  do  not  exist  both  on  the  surfaces  and  in  the  textures  whence 
these  capillaries  are  supposed  to  originate,  how  could  they  obtain  the  fluids  circulating 
in  them  ?  On  the  other  hand,  those  who  contend  for  the  existence  and  functions  of 
pores  cannot  deny  the  existence  of  minute  absorbents  or  lymphatics,  for  they  can  be 
demonstrated,  to  a  certain  extent,  as  respects  the  minuter  ramifications,  and,  in  a  satis- 
factory manner,  as  regards  the  more  considerable  brandies.  It  appears  to  us  that 
both  species  of  organization  exist  to  a  greater  or  less  extent  in  different  textures,  and 
secreting-  organs. 

Each  secreting  viscus,  is  supplied  with  a  distinct  ganglion,  plexus,  or  both ;  these 
preside  over  the  secreting  function,  and  the  functions  of  some  of  these  ganglia  are  in- 
fluenced by  the  operations  of  the  cerebro-spinal  system  ;  as,  for  example,  the  secretion 
of  the  lachrymal  gland  is  increased  by  the  influence  which  the  nerves  of  the  latter  sys- 
tem convey  to  the  ganglion  which  supplies  it,  and  is  the  chief  source  of  its  functions. 


Of  Nutrition. 
Note  C.  C.  and  S. 

As  we  have  already  seen,  in  the  notes  on  the  capillary  system  and  on  secretion,  the 
function  of  nutrition  has  been  explained,  by  one  class  of  Physiologists,  by  supposing 
the  existence  of  nutritive  capillaries,  and  by  another,  by  means  of.  organic  pores,  with 
which  they  endow  the  capillary  vessels  circulating  red  blood,  and  to  which  they  com- 
mit the  exhalent,  secreting,  and  nutritive  functions.  The  first  of  these  hypotheses 
supposes  that  nutrition  takes  place  in  minute  colourless  vessels,  which  proceed  in  a 
more  or  less  tortuous  direction  from  the  arterial  capillaries,  absorption  proceeding 
through  the  medium  of  a  similar  set  of  colourless  vessels  continuous  with  the  former, 
which  run  into  the  venous  capillaries,  and  thus  the  nutritious  molecules  are  always  cir- 
culating within  colourless  capillaries,  which,  with  the  nerves  and  larger  capillaries, 
constitute  the  basis  of  the  different  textures. 

Mascagni  supposes  that  the  arterial  capillaries,  at  the  point  where  they  change  into 
veins,  are  provided  with  exhalent  pores  both  for  the  purposes  of  secretion  and  nutri- 
tion ;  and  that  there  every  where  exist  the  orifices  of  minute  absorbent  vessels,  com- 
ifciencing  in  the  latter  description  of  pores,  in  order  to  take  up  the  nutritive  molecules. 
The  elementary  tissues  consist,  in  his  opinion,  of  the  particular  class  of  absorbent  ves- 
sels, which  contain  the  molecules  as  long  as  they  are  a  part  of  the  textures,  and  which 
by  their  union,  lorm  the  most  simple  membranes. 

'  These  hypotheses  do  not  differ  very  materially.  Both  contend  for  the  existence  of 
very  fine  capillaries  which  attract  the  nutritive  molecules,  and  contain  them  in  a  state 
of  progressive  circulation,  as  long  as  they  form  constituents  of  the  textures :  these 
molecules  being  afterwards  carried  onward  in  succession  into  the  branches  of  the  ab- 
sorbent lymphatics  and  into  the  veins.  In  the  first  of  these  hypotheses,  the  nutricious 
particles  are  supposed  to  circulate  in  the  finest  of  the  vessels  proceeding  from  the  ar- 
terial capillaries  ;  in  the  second,  the  process  is  ascribed  to  the  most  minute  radicles  of 
the  absorbents  ;  but  both  agree  in  considering  the  molecules  constituting  the  mass  of 
the  textures  to  be  contained  in  colourless  vessels,  and  to  be  in  a  state  of  continual  cir- 
culation. 

The  opinion  of  Bichat  on  this  subject  is  somewhat  different.  According  to  him, 
each  molecule  of  these  constituting1  the  textures  of  the  body  is  placed  between  the 
orifices  of  two  vessels :  one,  a  nutritive  exhalent  orifice,  which  has  deposited  the  mole- 
cule, the  other  a  nutritive  absorbent  orifice  about  to  absorb  it. 

Prochaska,  who  conceives  that  the  arterial  capillaries  are  continued  directly  into 
veins,  considers  that  nutrition  takes  place,  in  consequence  of  the  porosity  of  the  ca- 
pillaries, and  of  the  general  permeability  of  the  substances  constituting  the  mass  of 
the  structures.  M.  Richerand  espouses  a  similar  opinion,  but  he  seems  to  allow  ail 
organic  property  to  the  pores  which  lie  ascribes  to  the  capillary  vessels. 

Opinions  respecting  the  mechanism  of  nutrition,  or  the  manner  in  which  it  takes 
place,  can  only  be  theoretical.  We  have  not  the  means  of  demonstrating  the  exis- 
tence or  non-existence  of  either  the  one  or  the  other  mode  of  organization  contended 
fov:  each  may  of  itself  be  sufficient  to  explain  the  phenomenon,  as  far  as  respects  the 


OP  NUTRITION.  #1 

apparatus  required  for  the  process,  but  it  is  only  the  apparatus.  The  function  itself  13 
purely  a  vital  one.  It  presents  us  with  a  continual  motion  of  a  double  nut  are — a  con- 
tinual attraction  and  decomposition  of"  material  molecules.  In  the  most  simple  ani- 
mals, as  the  polypus,  these  processes  go  forward  without  any  previous  preparatory  func 
tion  :  the  aiiimai  imbibes,  in  a  direct  manner,  similar  molecules  of  matter  to  those  of 
which  it  is  its  formed  from  the  surrounding1  medium,  and  again  exhales  them  in  a  man- 
manner  equally  direct.  In  these  there  are  no  vessels  destined  for  the  purpose  of  circula- 
tidn  and  nutrition,  yet  they  present  the  phenomenon  of  irritability  ;  and  on  examina- 
tion, with  a  microscope,  their  structure  appears  almost  homogeneous,  with  the  excep- 
tion of  globules  entirely  similar  to  those  which  are  observed  in  the  ganglial  nerves  of 
the  higher  animals.  As  these  are  the  chief  mai'ks  of  internal  organization  which  can 
be  detected  in  the  very  lowest  of  the  animal  kingdom,  and  as  we  must  conceive  that 
the  organization  must  be  instrumental  inthe  nutrition  and  operations  of  animal  bodies : 
and  as,  moreover,  we  perceive  that  the  perfection  of  the  organization  or  material  appa- 
ratus is  commensurate  with,  and  has  an  evident  relation  to  the  extent  of  the  vital  opera- 
tions which  it  performs,  so  it  seems  reasonable  to  suppose  that  this  organization, 
which  is  the  only  one  to  be  detected  in  the  very  lowest  of  animals,  is  the  chief 
and  indeed  only  instrument  of  the  limited  function  which  these  animals  perform  ;  and 
that,  as  a  similar,  but  more  perfect  organization  presides  over  the  nutritive  function 
of  the  highest  animals,  so  this  presides  over  that  of  the  lowest,  without  the  assistance 
of  the  more  complicated  capillary  apparatus  assigned  by  some  physiologists  to  the  for- 
mer; and  if  a  distinct  set  of  subordinate  capillary  vessels  be  not  requisite  to  the  nutri- 
tive function  in  the  one,  we  may  allow  that  it  takes  place  in  the  other,  under  the  domi- 
nion of  the  more  perfect  nervous  organization  to  which  we  have  assigned  it,  without 
the  existence  of  the  more  complicated  capillary  apparatus  for  which  some  contend. 

Concluding,  therefore,  that  as  the  nervous  globules  demonstrable  in  the  very  lowest 
animals  are  the  only  organization  which  they  evince,  that  organization  must  have  a  de- 
terminate object  or  function  which  it  performs  under  the  control  of  the  vitality  with 
•which  it  is  allied,  and  which  all  animals  possess;  and  that  nutrition  and  irratibility  are 
the"  only  organic  actions  which  these  animals  perform,  so  it  must  inevitably  follow  that 
these  actions  result  from  the  vital  influence  allied  to  the  particular  organization  in  ques- 
tion, and  that  the  nervous  globules,  constituting  the  only  marks  of  internal  organization 
possessed  by  these  animals,  attract  from  the  surrounding  medium,  in  consequence  of  the 
vitality  with  which  they  are  allied,  these  molecules  of  matter  corresponding1  to  those 
forming  the  structure  of  the  animal,  which  come  within  the  sphere  of  their  influence,  and 
retain  them  for  an  indefinite  time,  without  either  the  medium  of  exhalent  or  absorbent 
vessels.  Now,  as  the  same  type,  especially  as  respects  the  nutritive  functions,  may  be 
observed  throughout  the  whole  animal  creation,  and  as  we  can  trace  nervous  cords, 
formed  of  globules  similar  to  those  already  ascribed  to  the  lower,  and  indeed  to  all  ani- 
mals, throughout  almost  the  whole  of  their  bodies,  is  it  not  reasonable  to  suppose  that 
similar  globules  exist  in  all  the  simple  textures  in  a  more  diffused  form — that  the  glo- 
bules constituting  the  organic  or  ganglial  system  of  nerves  become  more  disseminated 
amongst  the  molecules  of  the  textures  in  the  course  of  their  distribution  with  the  ca- 
pillary vessels,  or  of  their  more  direct  ramifications  and  terminations  in  the  textures 
themselves  ?  If  this  be  granted — and  it  scarcely  can  be  denied,  for  it  has  been  demon- 
strated in  different  orders  of  animals, — and  as  it  has  been  shown  that  these  nervous 
globules  are  present,  in  a  more  or  less  organized  form,  throughout  the  whole  animal 
creation,  it  i-may  consequently  be  inferred  that  the  same  function  which  we  have  as- 
cribed to  them  in  the  lowest  animals  should  be  extended  to  them  in  the  highest.  This 
is  conformable  to  the  laws  characterizing  the  animal  economy. 

As  we  have  contended  in  another  place,  conformably  with  this  opinion,  that  the  gan- 
glial nerves  in  some  one  or  other  of  their  forms  of  existence,  are  present  throughout 
every  part  of  the"  body,  that  they  preside  over  digestion,  nutrition,  secretion,  &c.  and 
are  more  nearly  allied  than  any  other  texture  with  the  vital  influence  which  the  body 
exhibits,  so  we  now  conclude  that  the  globules  constituting  the  ganglial  system,  being 
allied  with  vitality,  and  being  distributed  in  different  fonns  of  connexion  to  the  various 
textures  of  the  body,  exert,  in  consequence  of  the  vital  influence  with  which  they  are 
endowed,  a  vital  attraction  on  those  molecules  of  matter  which  come  within  the  sphere 
of  their  influence  ;  that  the  force  of  this  attraction,  and  the  manner  in  which  the  ma- 
terial molecules  are  arranged  In  order  to  form  the  different  textures  of  the  body,  result 
in  a  great  measure  from  the  influence  proceeding  from  the  form,  the  number,  or  the 
condition  of  these  globules  in  the  textures  which  it  is  their  office  to  perpetuate  ;  and 
that  the  chief  office  of  the  digestive,  the  respiratory,  the  animalizing,  and  the  circu- 
lating processes,  is  to  present  the  materials,  whence  the  different  textures  are  pre- 
served, in  a  fit  state  for  the  exertion  of  this  vital  attraction  ;  and  that  the  principal  ope- 
ration performed  by  the  capillary  vessels  is  to  convey  these  materials  within  the  spher; 


62  APPENDIX. 

of  this  attraction ;  and,  so  that  this  is  performed,  it  matters  but  little  whether  or  no 
these  vessels  accomplish  it  by  means  of  subordinate  nutritive  capillaries  destined  to  the 
circulation  or  deposition  of  the  nutritious  molecules,  or  by  means  of  organic  pores, 
with  which  the  parietes  may  be  provided. 

But,  whilst  we  suppose  that  the  function  of  nutrition  may  thus  take  place  in  conse- 
quence of  a  vital  attraction,  resulting  in  the  manner  which  we  have  explained,  and  ex- 
erted exterior  to  and  independently  of  the  vessels,  and  whilst  we  consider  this  expla- 
nation to  be  supported  by  the  nutritive  actions  of  the  lowest  animals,  yet  we  would  by 
no  means  exclude  the  influence  of  that  part  of  the  ganglial  nerves  distributed  to  the  ca- 
pillaries, from  a  part  in  the  operation,  more  especially  in  the  higher  classes  of  animals. 
Indeed  it  seems  difficult  to  suppose  which  of  those  in  the  higher  animals — namely, 
whether  the  nervous  globules  distributed  to  the  simple  textures,  and  placed  beyond 
the  capillaries,  or  those  constituting  the  nervous  fibrilhe  which  surround  them, — 
are  most  efficient  in  the  nutritive  process.  An  intimate  view  of  the  subject  would 
suggest,  that  in  man  and  the  more  perfect  animals,  the  latter  organization  is  the 
more  active  of  the  two  iu  the  operation  in  question  ;  and  that  the  capillary  vessels,  in 
consequence  of  the  ultimate  nervous  structure  which  surrounds  them,  and  of  the  vital 
influence  which  this  structure  exerts,  secrete  from  the  fluid  circulating  in  them  certain 
materials  in  a  similar  manner  to  that  in  which  they  perform  the  other  secretions  in  se- 
creting organs,  and  by  means  either  of  appropriate  vessels  or  pores. 

As  it  has  been  shown  that  the  blood  consists  of  minute  globules,  or  corpuscles  sur- 
rounded by  a  coloured  envelope  circulating  in  a  ma'ss  of  fluid,  and  that  the  simple  solids 
of  the  body  are  constituted  of  similar  corpuscles,  in  a  state  of  intimate  or  vital  attrac- 
tion, as  those  of  the  blood,  when  they  ai-e  separated  from  the  envelopes,  so  it  may  be 
inferred,  that  a  part  of  the  function  which  the  ultimate  distribution  of  the  ganglial 
nerves  perform  on  the  capillary  vessels,  is  to  secrete  similar  corpuscles,  from  the  blood 
circulating  in  them,  to  that  which  the  texture  possesses  in  which  the  operation  takes 
place  ;  and  that  this  having  been  accomplished,  the  vital  attraction  is  preserved  either 
by  means  of  the  influence  with  which  these  corpuscles  are  endowed,  as  a  consequence 
of  the  previous  process  of  animalization  which  they  have  undergone,  or  of  the  influence 
exerted  upon  them  after  they  leave  the  vessels  by  the  nervous  globules  and  fibrillas 
disseminated  in  the  textures,  or  perhaps  by  both  species  of  vital  action,  either  the  one 
or  the  other  acting  more  or  less*  partially  according'  to  the  nature  of  the  particular  tex- 
ture in  which  the  process  takes  place,  and  according  to  inappreciable  and  fortuitous 
causes. 

Hence  it  will  be  perceived  that  nutrition  is  essentially  a  vital  operation,  that  it  is 
placed  under  the  control  of  the  extreme  ramifications  of  a  particular  system,  to  which 
we  have  referred  all  the  vegetative  or  organic  operations  which  characterize  the  ani- 
mal kingdom  ;  that  it  is  performed  in  all  animals  except  the  very  lowest,  through  the 
medium  of  circulating  organs,  and  in  the  highest,  as  a  consequence  of  certain  prepara- 
tory processes ;  that  it  requires  in  man  and  in  the  higher  animals  a  capillary  circulation 
for  its  performance,  but  that  neither  of  the  capillary  apparatuses  which  have  been  con- 
tended for  is  sufficient  of  themselves  to  accomplish  it,  although  the  most  simple  of 
them  under  the  dominion  of  the  vital  influence  of  that  particular  structure  which  we 
find  every  where  disseminated  where  there  is  life,  is  all  that  is  requisite  as  the  material 
instrument  of  the  process ;  and  lastly,  and  as  a  consequence  of  the  foregoing  position* 
that  nutrition  is  modified,  controlled,  increased,  or  even  annihilated,  either  generally 
or  in  particular  parts  of  the  body,  by  the  state  of  the  vital  influence  allied  to  the  mate- 
rial organization,  to  which  we  have  already  imputed  it,  according  as  this  particular  or- 
ganization in  its  centres  and  ramifications  throughout  the  animal  frame  is  generally  or 
locally  affected. 


Of  the  Dedication  of  the  Optic  Nerves, 

Vicq  D'A.zyr,  found,  on  examining  with  the  microscope,  an  horizontal  section  of  the 
optic  nerves  of  the  human  subject,  after  it  had  been  hardened  in  alcohol,  that  the  me- 
dullary fibres  occupying  the  exterior  side  of  the  optic  nerve,  proceed  in  a  direct  man- 
ner from  the  optic  thalamus  to  the  eye  of  the  same  side ;  and  that  the  place  of  union 
presents  a  homogeneous  tissue  The  Wenzels  came  nearly  to  the  same  conclusion 
from  their  observations,  but  remarked,  in  addition,  that  while  the  fibres  of  the  exterior 
side  of  the  nerve  go  immediately  to  the  eye  of  the  same  side,  those  fibres,  placed  in  its 
interior  side  of  the  nerve  go  immediately  to  the  eye  of  the  same  side,  those  fibres, 
placed  in  its  interior  sid^,  are  directed  obliquely  towards  the  other  nerve,  without, 


OP  THE  FORMATION  OF  THE  SPINAL  MARROW  AND  BRAIlSf.      53 

however,  any  crossing  of  fibres  being1  manifest  at  the  point  where  the  junction  of  both 
nerves  take  place. 

M.  Treviranus  has,  in  a  great  measure,  confirmed  these  observations,  on  the  male 
simia  avgiila.  The  nerves  and  brain  were  left  during  some  months  in  alcohol,  and  af- 
terwards kept  some  time  in  caustic  potash  to  soften  them.  Having  thus  prepared 
them,  he  submitted  them  to  a  careful  dissection,  when  he  made  out,  with  the  aid  of 
a  microscope,  that  the  external  fibres  of  the  upper  side  of  each  were  continued  from 
their  cerebral  extremity  to  that  in  the  eye,  without  uniting1  themselves  to  those  of  the 
other  side  ;  whilst,  on  the  contrary,  the  internal  and  inferior  fibres  of  one  nerve  went 
to  the  other  side,  and  united  with  the  fibres  of  the  opposite  nerve.  It  was  difficult  to 
determine  whether  any  of  the  fibres  actually  passed  from  one  side  to  the  other.  He 
thought,  however,  that  sume  of  the  fibres  di'd  so.  The  internal  fibres,  thus  interlacing 
together,  were  evidently  more  numerous  than  the  external  fibres  which  ran  to  the  eye 
without  uniting  with  those  of  the  opposite  nerve — Journal  Complementaire,  Oct.  1823. 


On  the  Motions  of  the  Eye. 

Mr.  Charles  Bell  has  lately  examined*  the  motions  of  the  eye,  in  illustration  of  the 
uses  of  the  muscles  of  the  orbit;  and  has  shown,  in  the  first  place,  that  there  are  mo- 
tions performed  by  this  organ  not  hitherto  noticed.  Every  time  the  eyelids  descend  to 
cover  the  transparent  part  of  the  eye,  the  eyeball  ascends,  or  suffers  a  revolving  mo- 
tion. If  this  were  not  the  case,  the  surface  of  the  eye  would  not  be  moistened,  nor 
freed  from  offensive  particles.  He  has  proved,  in  the  next  place,  that  during  sleep  the 
eyeball  is  turned  up,  and  the  cornea  lodges  secure  and  moistened  by  the  tears,  under 
cover  of  the  upper  eyelid.  He  considers  that  these  motions  are  rapid  and  insensible, 
and  that  they  are  provided  for  the  safe-guard  of  the  eye.  The  other  motions  are  vo 
luntary,  and  for  the  purpose  of  directing  the  eye  to  objects. 

Mr/Bell  next  examined  the  actions  of  the  muscles  of  the  eyeball,  and  distinguished 
them,  as  usual,  into  the  straight  and  oblique  muscles.  It  has  been  supposed,  hitherto, 
that  both  these  classes  of  muscles  were  voluntary ;  some  describing  the  oblique  as  coad- 
jutors of  the  recti  muscles,  and  others  as  opponents  to  the  recti ;  but  Mr.  Bel!  has 
viewed  the  oblique  as  provided  for  the  insensible  motions  of  the  eyeball,  and  the  recti 
for  those  motions  wThich  are  directed  by  the  will,  and  of  which  we  are  conscious. 

Mr.  B.  has  also  proceeded  to  show,  that,  the  consciousness  of  the  action  of  the  recti 
muscles  gives  us  the  conception  of  the  place  or  relation  of  objects ;  and  has  endea- 
voured to  prove,  by  observation  and  experiment,  that  the  actions  of  the  straight  mus- 
cles are  inseparably  connected  with  the  activity  of  the  retina;  that  is,  with  the  enjoy- 
ment of  vision  :  but  that  the  moment  the  vision  is  unexercised,  the  eyeball  is  given 


May,  1823, 


Of  the  Formation  of  the  Spinal  Marrow  and  Brain. 
Note  DD. 

I.  Of  the  Formation  of  the  Spinal  Marroio. — The  researches  of  M.  Tiedemann,  the 
Wenzels,  Doellinger,  Cams,  and  Desmouiins,  have  furnished  us  with  much  interesting 
information  on  this  subject.  The  soft  and  gelatinous  state  of  the  embryo  at  the  ear- 
liest periods  of  its  existence,  the  rapidity  of  its  metamorphoses,  and  the  difficulty  of  de- 
monstrating, owing  to  its  colour  and  consistency,  that  part  of  the  nervous  system,  which 
from  the  circumstance  of  its  supplying  those  parts  of  the  embryo  that  are  first  formed, 
as  well  as  from  other  considerations,  we  are  led  to  consider  as  the  first  which  assumes 
an  organized  appearance,  combine  to  render  the  exact  origin  of  the  spinal  marrow  diffi- 
cult, if  not  impossible  of  demonstration.  Reasoning  from  the  condition  of  the  nervous 
Astern  throughout  the  scale  of  the  animal  kingdom,  from  the  manner  in  which  the  dif- 


£4  APPENDIX. 

ferent  organs  seem  to  be  formed,  from  the  organization  of  some  monstrous  foetuses, 
and  from  other  considerations  on  which  we  cannot  enter  at  this  place,  we  are  disposed 
to  conclude,  that  the  spinal  marrow  is  itself  produced  from  the  ramifications  of  the 
sympathetic  ganglia ;  that  the  scmilunar  ganglion  is  the  first  part  of  the  nervous  sys- 
tem to  assume  an  organized  state  ;  and  that  the  subordinate  ganglia,  the  spinal  marrow, 
and  lastly  the  brain,  come  successively  into  existence,  and  gradually  arrive  at  their  full 
developement. 

It  is  not  until  about  the  third  or  fourth  -week  that  a  greyish-white  fluid  may  be  de- 
tected in  the  cavities  of  the  head  and  spine.  From  the  fourth  to  the  fifth  -week  the  me- 
dulla  eblongata  may  be  distinctly  seen.  It  is  then  about  twice  as  thick  as  the  medulla 
spinalisy  which,  before  the  developement  of  the  limbs,  is  of  an  equal  thickness  through- 
out its  whole  length,  and  presents  a  slight  curvature  near  the  commencement  of  the 
medulla  oblongata,  owing  to  the  flexion  of  the  head  upon  the  chest.  The  spinal  marrow 
at  this  time  consists  of  two  white  strips  of  medullary  matter,  which  offers  a  manifest  de- 
cussation  at  the  place  where  it  curves  forwards  at  the  margin  of  the  inferior  extremity 
of  the  pyramids.  It  is  not,  however,  the  whole  of  the  two  cords  of  the  marrow  that 
cross,  but  the  middle  or  pyramidal  fasciculi  of  each.  The  spinal  marrow  descends 
from  this  point  through  the  whole  extent  of  the  canal  to  the  interior  of  the  caudal  pro- 
longation. 

At  the  fifth  -veek  these  stripes  or  chords  form  a  junction  of  their  interior  and  ante- 
rior margins,  a  longitudinal  gutter  :  their  external  and  posterior  magins  are  then  full  and 
prominent. 

At  the  seventh  iveek  the  spinal  marrow  is  open  throughout  its  whole  length.  On  each 
side  of  the  fourth  ventricle,  a  straight  thin  lamina  is  put  forth,  which  inclines  from  with- 
out inwards,  applying  itself  to  that  of  the  opposite  side,  without,  however,  uniting  with 
it :  these  are  the  rudiments  of  the  cerebellum,  springing  from  the  restiform  bodies.  The 
cervical  enlargement  begins  to  appear,  particularly  its  cephalic  extremity.  The  for- 
mation of  the  limbs  coincides  wit^h  that  of  the  corresponding  enlargements  of  the  chord. 

The  longitudinal  raphe,  formed  by  the  aproach  of  the  interior  margins  of  -the  two 
chords  constituting  the  marrow,  is  continued  upwards,  and  separates  the  tubercles,  that 
is,  the  laminse  which  represent  them  :  the  optic  thalami  are  devolved. 

At  the  commencement  of  the  third  month,  the  marrow  is  still  open  at  its  superior  half, 
and  extends  to  the  extremity  of  the  sacrum.  The  tubercula  quadrigemina  are  volumin- 
ous, hollow  and  separated  by  the  median  furrow  :  the  optic  thalami  are  full.  The  two 
cervical  and  lumbar  prominences  are  a  third  of  a  line  thicker  than  the  body  of  the  mar- 
row: Tiedemann  has  not  observed  the  junctions  of  its  exterior  margins  until  the  end 
of  the  third  month.  Serres  has  seen  it  a  fortnight  earlier.  This  junction  takes  place 
from  beneath  upwards. 

At  twelve  -weeks  the  marrow  extends  only  to  the  middle  of  the  sacrum.  The  tubercula 
quadrigemnia  are  united  and  form  a  canal ;  at  this  period  the  mammillary  eminences 
and  the  corpora  striata  may  be  seen.  The  internal  canal,  which  is  now  formed  by  the 
junction  of  the  margins  of  the  marrow  communicates  with  the  fourth  ventricle.  Ac- 
cording to  M.  Desmoulins,  this  canal  results  from  a  sinus,  formed  by  the  fold  of  the  pia 
mater  as  it  dips  into  the  interior  of  the  marrow,  or  rather  between  both  the  cords  of 
which  the  marrow  is  then  formed.  The  precise  period  at  which  this  canal  is  com- 
pletely obliterated,  has  not  been  ascertained.  M.  Carus  conceives  that  the  pectoral 
portion  of  the  marrow  is  the  first  to  close,  and  that  the  canal  is  obliterated  along  its 
whole  extent,  owing  to  the  formation  of  the  gray  substance. 

At  the  fourth  month,  the  spinal  marrow  reaches  only  to  the  base  of  the  sacrum;  the 
cervical  eminence  is  larger  than  the  lumbar.  The  two  contiguous  cords  of  the  marrow 
divide,  in  the  medulla  oblongata,  each  into  three  others  much  smaller.  The  internal 
or  pyramidal  forms  a  tolerably  broad  surface,  as  in  fishes  and  reptiles,  and  evidently 
crosses,  as  was  already  noticed,  with  that  of  the  other  side  about  the  fourth  or  fifth 
week  of  the  foetal  life.  The  middle  cord,  or  the  corpus  oblivare,  is  placed  above  the 
former;  some  of  its  fibres  ascend  to  the  tubercula  quadrigemitui,  and  unite  with  those 
proceeding1  from  the  opposite  side,  in  order  to  form  the  vault  of  the  aqueduct  of  Syl- 
vius. The  external  or  restiform  cord,  proceeding  from  the  lateral  and  posterior  por- 
tion of  the  marrow,  forms  the  prominent  paries  of  the  fourth  ventricle,  and  advances 
into  the  cerebellum.  At  this  period  the  annular  protuberance  is  perceptible.  The 
interior  canal  of  the  marrow  is  now  very  narrow,  and  still  communicates  with  the  fourth 
ventricle.  It  is  not  until  towards  the  end  of  the  fourth  month  that  the  lumbar  and  sa- 
cral nerves  become  elongated,  and  form  what  has  been  improperly  called  the  caiirla 
equina,  which  at  first  does  not  exist.  The  pia  mater  which  penetrates  by  the  posterior 
median  furrow,  is  observable  in  the  centre  of  the  marrow. 


01?  THE  CEREBRO-S FINAL  SYSTEM.  £5 

At  thejifth  mnnth,  the  pyramidal  eminences  are  evident :  there  still  exists  a  commu- 
nication between  the  fourth  ventricle  and  the  canal  of  the  marrow.  The  two  swellings 
of  the  cord  are  well  marked.  The  annular  protuberance  becomes  more  distinct,  and 
the  corpora  siriata  are  large.  The  increased  thickness  of  the  tubercles  has  narrowed 
considerably  the  cavity  which  they  formed  by  their  approach.  The  marrow  extends  at 
this  period  no  farther  than  the  margin  of  the  fifth  lumbar  vertebra. 

The  human  embryo  possesses  a  caudal  prolongation  until  the  fourth  month  of  uterine 
life.  At  this  period  it  disappears,  and  its  disappearance  coincides  with  the  ascension  of 
the  spinal  marrow  in  the  vertebral  canal.  If  the  ascension  of  the  marrow  is  arrested, 
the  human  fetus  is  born  with  a  tail,  as  has  been  observed  in  several  cases.  The  cir- 
cumstance of  the  spinal  marrow  descending1  lower  in  the  vertebral  canal  the  younger  the 
foetus,  has  attracted  the  particular  notice  of  those  physiologists,  to  whose  researches  we 
are  indebted  for  our  knowledge  of  the  subject  under  consideration.  M.  Tiedemann, 
who  offers  the  most  rational  explanation  of  this  phenomenon,  supposes  that  the  marrow 
descends  not  so  far  in  the  canal  of  the  full-grown  fetus,  as  in  that  of  the  early  embryo, 
because  the  vertebral  column  grows  more  rapidly  in  length,  than  the  nervous  Cord 
tvhich  it  is  destined  to  protect. 

To  wards  the  end  of  the  sixth  month,  the  corpora  vlivaria  form  a  well-marked  lateral 
projection.  At  this  epoch  may  be  seen  the  internal  and  middle  cords,  forming  the  pe- 
duncles of  the  brain,  plunging  into  the  optic  thalami  which  they  formed  by  their  en- 
largement. The  fibres  composing  them  may  be  perceived  on  scraping  away  a  thick 
pulpy  layer  from  their  interior  and  superior  aspect.  A  few  fibrous  portions  detach 
themselves  from  their  internal  side,  and  proceed  outwards  to  the  mammillary  eminence. 
All  the  other  fibres  continue  to  advance  from  behind  forwards,  and  from  within  out- 
wards, beneath -the  corpora  striata,  and  proceed,  in  a  diverging  form,  to  the  cerebral 
lobes.  A  few  fibres  may  be  seen  entering  them.  In  the  course  of  the  sixth  month 
the  transverse  furrow  separating  the  eminentia  quadrig'endna  begins  to  appear,  or  rather, 
each  of  these  prominences  becomes  more  developed. 

At  the  seventh  month,  the  length  of  the  marrow  is  nearly  the  same.  The  transverse 
fibres  which  compose  the  annular  protuberance  are  now  distinct,  and  they  may  be  seen 
interlacing  with  those  of  the  pyramids.  This  part  results  from  the  following  disposi- 
tion ;  the  fibres  of  one  lateral  hemisphere  of  the  cerebellum  are  continued  beneath  the 
spinal  marrow  with  the  fibres  of  the  opposite  hemisphere,  by  layers  which  alternate 
with  the  planes  of  fibres  proceeding  obliquely  from  the  pyramids  to  the  optic  thalami. 

At  the  eighth  month  the  marrow  reaches  only  to  the  fourth  lumbar  vertebra,  and  at 
the  ninth  month  it  is  at  the  margin  of  the  third.  The  interior  canal  of  the  marrow  still 
exists,  and  remains  until  from  six  months  to  a  year  after  birth.  It  is  at  the  last  months  of 
gestation  that  the  disposition  of  the  medullary  fibres  of  the  marrow  may  be  most  dis- 
clistinctly  traced,  and  the  mode  of  formation  of  the  mesocephalon  or  pans  Varolii, 
which  is  only  a  continuation  of  the  marrow,  becomes  most  evident. 

All  the  white  or  medullary  parts  which  are  seen  at  the  base  of  the  brain,  manifestly 
arise  from  the  superior  part  of  the  spinal  marrow.  (OLLIVIEH.  sur'le  Beveloppemeitf  d& 
la  Moelle  Opiniere.) 


II.  Of  the  Formatioji  of  the  Brain.— -The.  interesting  results  of  Dr.  Tiedemann's  re- 
searches on  this  subject  may  be  reduced  to  the  following  heads  : 

"  1.  In  the  commencement  of  pregnancy,  especially  about  the  second  month,  the 
earliest  period  at  which  the  brain  can  be  rendered  perceptible  by  the  action  of  alcohol, 
this  organ  is  very  small  in  proportion  to  the  spinal  marrow.  In  fact,  it  results  from  the 
prolongation  upward  and  forward,  of  the  two  principal  cords,  the  olivary  and  pyrami- 
dal. All  its  superior  part  is  open,  or,  more  properly  speaking,  forms  a  broad  gutter, 
which  at  once  comprehends  the  third  ventricle,  the  aqueductus  sylvii,  the  fourth  ven- 
tricle, and  calamus  scriptorius.  This  gutter  is  interruptedly  continuous  with  the  canal, 
which  traverses  the  whole  length  of  the  marrow. 

'*  2.  The  cerebellum  evidently  originates  from  the  spinal  marrow  ;  from  the  lateral 
parts  of  which  arises,  on  each  side,  a  small  flattened  cord.  These  two,  at  first  so  dis- 
tinct and  separate  that  they  may  be  readily  parted  without  laceration,  afterwards  unite 
so  as  to  form  ttie  roof  of  the  fourth  ventricle.  Then  only  the  brain,  viewed  from  above, 
ceases  to  represent  a  gutter ;  and  the  lamina:  and  branches  of  the  cerebellum  are  formed 
at  a  much  later  period. 

"3.  The  mass  which  supports  the  tubercula  quadrigemina  equally  shows  itself  in  its 
origin,  under  the  form  of  two  small  thin  membranes,  which  arise  from  the  olivary  cords 

I 


66  APPENDIX. 

of  the  spinal  marrow,  and  which,  when  they  cease  to  be  distinct,  represent  a  vault  co- 
vering a  large  ventricle,  whose  successive  contraction  gives  rise  to  the  aqueductus 
sylvii. 

"  4.  The  pyramidal  cords  of  the  spinal  marrow,  which  take  a  direction  below  up- 
ward, and  from  bekind  forward,  after  having  produced  two  swellings,  or  ganglia,  the 
optic  thalami,  and  corpora  striata,  each  terminate  by  a  lamina,  which  bent  from  before 
backward,  and  from  the  side  towards  the  superior  and  internal  part,  forms  the  com- 
mencement of  the  hemisphere  of  the  brain.  These  membranes  and  thin  hemispheres 
are  so  small  at  the  second  month,  that  they  scarcely  cover  the  corpora  striata.  In  pro- 
portion -as  they  increase  they  extend  backward,  and  cover,  at  the  third  month,  the  optic 
thalami ;  at  the  fourth,  the  tubercula  quadrigemina ;  and,  at  the  sixth  or  seventh,  the 
cerebellum.  The  lateral  ventricles  result  from  their  inversion. 

"5.  The  medullary  fibres  of  the  pyramidal  cords,  previously  to  the  formation  of  the 
tuber-annulare,  are  immediately  continuous  with  those  of  the  crura  cerebri ;  from 
whence  the  eye  may  readily  trace  them  in  the  optic  thalami,  and  corpora  striata,  and  see 
them  aftewards  spreading  and  radiating  in  the  hemispheres. 

"  fl.  The  parietes  of  the  hemispheres  gradually  increase  in  thickness  in  proportion  as 
new  strata  of  cerebral  substance  are  deposited  on  the  surface  ;  and  convolutions-  are  not 
decidedly  seen  till  towards  the  close  of  pregnancy. 

"  All  these  combined  facts  clearly  demonstrate,  in  the  opinion  of  Dr.  Tiedernann,  that 
the  brain  and  cerebellum  proceed  from  the  spinal  marrow  :  or  that,  to  employ  a  mo- 
dern expression,  they  are  an  efflorescence  of  it.  In  running  through  the  scale  of  ani- 
mals, ample  confirmation  may  be  found  of  the  assertions  here  advanced.  The  structure 
of  the  encephalon  and  spinal  marrow  becomes  complicated  in  proportion  as  we  ascend 
from  fishes  to  reptiles,  birds  and  mammalia.  If  the  contrary  opinion  were  correct— if 
the  spinal  marrow  were  derived  from  the  brain,  the  cerebrum  and  cerebellum  must  ne- 
cessarily be  found  the  first  formed  in  the  foetus,  which  is  not  the  case.  It  is  equally 
necessary  that,  in  the  animal  scale,  where  it  is  impossible  to  mistake  a  gradation  in  the 
figure  and  developement  of  the  organs,  that  a  complete  brain  should  exist  previously  to 
any  trace  of  a  spinal  marrow  ;  but  this  is  never  observed.  Comparative  anatomy,  on 
the  contrary,  shows  that  the  spinal  marrow  is  very  large  in  the  inferior  classes  of  ani- 
mals, while  the  brain  forms  but  a  small  and  delicate  prolongation  of  it ;  and  in  ascend- 
ing from  reptiles  to  birds  and  mammalia,  it  is  seen  gradually  to  increase  in  volume  and 
complication,  as  abs6lutely  takes  place  in  the  foetal  encephalon*. 


*  Prochaska  and  the  Wenzels  conclude  from  their  microscopic  observations,  that  the 
brain  is  composed  of  a  number  of  small  globules  of  a  tolerably  firm  consistence  con- 
tained in  a  flocculent  pulp.  The  researches  of  Mr.  Bauer  into  the  ultimate  structure  of 
this  organ  are  more  precise.  He  considers  that  the  brain  and  nerves  consist  of  extemely 
delicate  fibres,  formed  of  minute  globules,  connected  together  by  a  transparent  gelan- 
tinous  fluid,  or  viscid  mucus,  which  is  soluble  in  water.  These  globules  vary  in  dimen- 
sions, from  •j-g—  Q-  to  -j-^Q-g-  parts  of  an  inch.  "  The  principal  difference,"  he  states,  "  in 
the  appearance  of  the  different  parts  of  the  brain,  consists  in  the  proportions  which  the 
quantity  of  mucus  and  fluid  bear  to  the  quantity  of  globular  tissue,  and  in  some  measure,, 
in  the  size  of  the  globules.  The  cortical  substance  of  the  cerebrum  and  cerebellum 
is  made  up  by  the  small  globules,  the  gelantinous  fluid  and  mucus  being  very  abundant. 
The  medullary  substance  in  the  cerebrum  and  cerebellum  differs  from  the  above,  in 
the  large  globules  prevailing,  the  mucus  being  more  tenacious  and  less  abundant.  The 
crura  cerebri  and  cc  rebelli  resemble  the  medullary  substance,  only  that  the  mucus  and 
fliu  Is  are  more  abundant,  and  in  greater  proportion  than  the  globules. 

The  medulla  oblongata,  the  corpora  pyramydalia,  and  olivam,  have  nearly  the  same 
structure  as  the  medullary  substance,  but  the  mucus  is  very  abundant.  In  the  medul- 
la spinalis,  the  mucus  and  fluid  are  less  tenacious,  but  in  greater  quantity  than  in  any 
part  of  the  brain. 

Every  part  of  the  brain  is  pervaded  by  innumerable  bloodtvessels,  which  are  of  consi- 
derable size  towards  the  centre,  but  branch  out  to  an  extreme  degree  of  minuteness  ; 
but  even  then  carry  red  blood.  The  arteries  in  the  brain  never  anastomose,  and  are 
accompanied  by  veins  still  smaller,  which  are  supplied  with  valves. 

This  view  of  the  structure  of  the  cerebrum  and  cerebellum  is  calculated,  In  the  opi- 
nion of  Sir  Everard  Home,  to  throw  considerable  light  on  the  functions  of  the  brain. 
He  thinks  that  the  cortical  substance  is  one  of  the  most  essential  parts  of  this  organ, 
and  considers  it  the.  seat  of  memory,  from  having  observed  that  that  faculty  is  destroyed 
or  materially  diminished  by  any  undue  pressure  upon  the  upper  anterior  part  of  the 


OF  THE  CERfcBKO-SPlNAL  SYSTEM. 


Of  the  Functions  of  the  Cerebro-spinal  System  of  Nerves. 

I.  General  t'/ew  of  t fie  J\"ervous  System. — At  a  former  part  of  these  notes  we  divided 
the  nervous  system  into  two  principal  orders,  viz  the  ganglial  or  vital,  and  the  cerebro- 
spinal.  Of  the  former  we  remarked,  that  the  globules  of  which  it  is  constituted  are  disse- 
minated in  the  structure  of  the  Zoephyta,  are  organized  into  a  homogeneous  ganglion, 
but  imperfectly  developed  in  many  of  the  orders  of  the  Ecliinvdennata,  and  are  arrang- 
ed into  ganglia  communicating  by  means  of  intermediate  cords  in  the  JlnneUdee,  Cirrhi- 
pedes,  &c.  The  homogeneous  nature  of  the  ganglions  disappears  as  the  animal  is  pro- 
vided with  separate  organs,  especially  with  those  devoted  to  the  senses  :  and,  with  the 
development  of  separate  organs,  accessary  or  subordinate,  ganglions  make  their  appear- 
anee,  which  latter,  in  the  progressive  rise  in  the  scale  of  the  animal  kingdom,  assume  in 
the  anterior  part  of  the  body  of  the  animal  the  character  of  the  rudiments  of  an  ence- 
phalon.  So  long  as  there  exists  only  simple  ganglia  without  any  spinal  cord,  the  gan. 
glion  representing  the  rudiments  of  an  enoephalon,  surrounds  the  oesophagus  in  the 
manner  of  a  ring.  This  encephalic  ganglion  is  intimately  connected  with  the  ganglial 
functions,  and  presides  over  those  imperfect  operations  of  sense  with  which  the  ani- 
mal is  endowed,  and  which  are  those  more  immediately  subordinate  to  its  fttnctions  of 
nutrition,  and  to  its  immediate  preservation, 

In  all  animals  possessing  no  other  rudiments  of  the  cerebro-spinal  system,  than  an  ac- 
cessary ganglion  disposed  around  the  oesophagus,  the  manifestation  of  volition  is  by  no 
means  distinct;  their  movements  appear  to  be  the  result  neither  of  reflection  nor  of 
choice.  An  obscure  instinct  seems  to  be  the  actuating  principle  of  those  operations, 
which  may  assume  in  them  the  nearest  resemblance  to  those  of  volition. 

As  we  rise  in  the  scale  of  the  animal  creation,  and  as  we  perceive  the  relation  be- 
tween the  exterior  world  and  the  animal,  to  be  more  extended  and  intimate,  owing  to 
the  extension  and  perfection  of  the  organs  of  sense  and  volition,  so  we  perceive  the  ce- 
rebro-spinal system  more  perfectly  organized,  more  fully  developed,  and  more  compli- 
cated in  its  structure.  With  the  formation  of  the  spinal  cord,  in  the  class  of  fishes,* 
the  accesary  encephalic  ring  or  ganglion  disappears,  and  the  encephalon  is  surrounded 
by  a  protecting  case,  which  is  continued  over  the  cord  itself. 

The  diversity  and  complication  of  the  parts  constituting  the  encephalon  increase  as 


mass  composed  of  two  symmetrical  hemispheres,  the  prototype  of  the  cerebral  hemis- 
pheres of  all  the  superior  classes. 

brain,  as  in  that  requiring  the  operation  of  trepan.  In  hydrocephalus,  on  the  other 
hand,  where  the  fluidi  s  in  large  quantity,  and  there  only  remains  the  cortical  part  of 
the  brain,  and  pons  Varolii,  all  the  functions  go  on,  and  the  memory  can  retain  passages 
of  poetry.  In  one  case,  slight  pressure  upon  the  sinciput  produced  complete  derange- 
ment, and  violent  excesses  of  the  passion  of  lust,  which  went  off  by  removing,  by  tiie 
trepan,  the  depressed  bone. 

The  veins  being  so  minute,  and  being  supplied  with  valves,  perform  in  the  opinion 
of  this  physiologist,  the  office  of  absorbents — which  have  never  been  observed  in  the 
brain — and  carry  the  absorbed  matter  into  the  superior  longitudinal  sinus,  which  ap- 
pears more  a  reservoir  than  a  vein. 

The  transparent  mucus  being  not  only  one  of  the  most  abundant  materials  of  which 
the  brain  itself  is  composed,  but  also  the  medium  by  which  the  globules  are  kept  to- 
gether, and  serving  the  same  purpose  in  the  nerves,  Sir  E.  H.  thinks  that  the  commu- 
nication of  sensation  and  volition  depends  apon  it.  He  concludes  from  all  his  experi- 
ments a;id  observations,  that  this  fluid,  as  well  as  the  principal  materials  of  which  the 
body  is  composed,  are  met  with  in  the  blood. 

*  M.  Desmoulins  has  lately  shown  that  many  reptiles  and  several  fishes  offer  not  a 
trace  of  grey  substance  in  their  spinal  cords,  and  that  on  the  contrary,  this  part  is  en- 
tirely composed  of  white  substance.  He  has  also  found  that  the  sturgeon  is  entirely 
\vithout  a  cerebellum  ;  and  that  its  fourth  ventricle  possesses  a  considerable  extent. 

He  concludes  that  the  dimensions  and  extreme  development  of  the  fourth  ventricle 
always  coincides  with  the  extreme  development  of  the  eighth  pair  of  nerves.  The  cir- 
cumstance of  the  grey  substance  being  wanting  in  the  spinal  cord  of  some  fishes  mili- 
tates against  the  opinion  of  M.  OLlivier  stated  at  a  subsequent  page. 


68  APPENDIX. 

In  another  part  of  these  notes  we  gave  a  full  detail  of  the  progressive  development  of 
the  cerebro-spim-1  system  of  nerves  in  the  human  ftctus.  It  will  readily  appear  from 
what  we  there  advanced,  that  a  similar  gradation,  (from  the  simplest  to  the  most  com- 
plicated and  perfect  state  of  the  Y,-; -.  vous  structure,)  to  that  which  we  observe  in  ascend- 
ing the  scale  of  the  animal  creation,  may  L-e  remarked  in  the  changes  which  the  nervous 
system  undergoes  in  the  progressive  evolution  of  the  human  embryo.  In  the  lowest 
of  all  the  animal  kingdom  the  nervous  matter  is  not  organized  in  a  manner  distinct 
from  the  tissue  constituting  the  anim?l :  the  nervous  globules  are  disseminated  through 
an  amorphous  and  pulpy  mass.  As  we  ascend  the  scale  we  perceive  this  particular  struc- 
ture arranged  in  succession  into  ganglia  ;  then  into  ganglia  and  spinal  marrow  ;  and  lastly 
into  ganglia,  a  spinal  marrow  and  a  brain, — each  becoming  more  perfect  as  we  ascend  the 
scale,  and  the  gradation  from  the  one  to  the  other  being  nearly  unappreciable  in  the 
species  or  genera,  but  sufficiently  remarkable  in  the  orders.  A  development  of  the 
nervous  system,  in  which  a  similar  progression  to  this  is  observed,  takes  place  in  the 
formation  of  the  human  fa-tus,  and  in  that  of  the  most  perfect  animals  ;  and  a  similar 
type  to  that,  in  which  this  system  exists  in  the  lower  orders,  is  adopted  at  first  in  the 
highest,  and  preserved, — every  successive  state  of  organization  which  this  system  as- 
sumes in  its  progressive  development  being  additions  to  that  previously  adopted,  whilst 
in  the  process  of  formation  as  respects  the  entire  animal,  each  intermediate  series  from 
the  lowest,  which  is  its  first  state  of  existence  in  the  embyro,  is  successively  passed 
through,  until  the  foetus  arrives  at  that  specific  condition  and  stage  of  organization  be- 
stowed on  the  species  to  which  it  belongs.  Thus  the  human  foetus  in  the  progress  of 
its  formation,  as  respects  both  its  nervous  system  and  other  organs  and  textures,  runs 
through  the  different  grades  of  organization  from  the  lowest,  to  that  of  the  head  of  which 
it  is  itself  placed,  j-  (  See  the  Note  on  the  Development  of  the  Fatus. ) 

II.  Of  the  Functions  of  distinct  parts  of  the  Cerebro-Spinal  Order  of  the  J\ervous  Sys- 
tem— The  researches  of  M.  Flourens  into  the  functions  of  the  cerebro-spinal  order  of 
nerves,  have  lately  added  greatly  to  our  knowledge  as  to  actions  in  which  distinct  parts 
of  this  part  of  the  nervous  system  are  more  particularly  concerned.  But  before  we 
can  give  any  account  of  the  conclusions  at  which  he  has  arrived,  we  must  briefly  no- 
tice the  meaning  lie  has  attached  to  some  of  the  terms  which  he  employs. 

The  term  contractibility  he  very  properly  limits  to  the  property  inherent  in  the  mus- 
cular fibre  only,  of  undergoing  brisk  contractions  under  the  application  of  stimuli :  and. 
the  term  sensibility,  to  imply  the  property  of  experiencing  sensations.  The  word  irri- 


f  Sir  Everard  Home,  Merrs.  GeofFroy  Saint  Hilaire  and  Blainville  and  Dr.  Schultze, 
consider  that  the  skeleton  of  animals  was  intended  more  to  prevent  the  nervous  and 
vascular  system  from  being  compressed  or  suffering  any  other  injury,  than  to  give  form 
and  the  power  of  motion  to  the  body.  The  last  named  physiologist  (Jlllgemeine  En- 
tyclopccdiefur  Practische  Jlrx'.e  und  Wundarzte,  1  theil,  1  band  Ltip.  1 820.)  concludes  : 

1°  "  That  the  spinal  marrow  and  vertebral  column  at  all  times  exist  together,  even 
only  the  slightest  vestiges  of  the  osseous  system  can  yet  be  found. 

2°  "  That  the  osseous  and  nervous  systems  have  between  them  numerous  intimate 
relations,  both  physiological  and  pathological. 

3°  "  That  the  more  the  exterior  hard  envelopment  penetrates  the  interior  of  the  bo- 
dy, and  approaches  towards  the  nervous  system,  the  more  also  are  the  phenomena  of 
sensibility  developed,  and  nice  vtrsa. 

4.  "  That  the  organs  possess  more  or  less  importance  according  as  they  are  more  or 
less  protected  from  external  influence  by  bones." 


The  blood  proceeding  from  the  mass  of  muscles,  spine  and  spinal  marrow,  is  empti- 
ed into  the  great  spinal  veins,  as  into  a  reservoir  ;  when  it  passes  into  the  veins  placed 
on  the  sides  and  anterior  surface  of  the  spine,  and  thence  into  the  superior  und  inferior 
cavs:. 

By  what  power,  it  has  been  asked,  is  the  blood  which  arrives  in  the  two  great  spinal 
veins,  driven  from  them  ?  These  veins  may  effect  the  propulsion  of  the  blood  which 
they  contain,  by  the  vital  properties  with  which  they  are  endowed ;  the  blood  may  be 
drawn  oui  of  them,  owing  to  their  proximity  to  the  cava  by  the  dilatation  of  the  cavities 
of  the  heart :  or  by  both  influences  combined. 


OF  THE  CEREBRO-SPINAL  SYSTEM.  69 

lability^  he  applies  to  the  property  of  exciting  sensation  and  motion,  without  evincing 
or  experiencing  them.  This  application  of  the  word  is  by  no  means  judicious;  it  must 
however,  be  allowed,  that  it  i3  not  easy  to  find  a  term  which  can  convey  the  meaning 
wished  to  be  attached  to  it. 

The  questions  proposed  by  Mr  Flourens,  and  which  he  lias  endeavoured  to  ascertain 
by  experiment  are  : — 1st,  from  what  points  of  the  nervous  system  artificial  irritation  may 
jet  oft' to  arrive  at  a  muscle  ;  2cl,  to  what  points  of  this  system  an  impression  must  be 
propagated  to  produce  sensation  ;  3d,  from  what  points  voluntary  irritation  descends, 
and  what  parts  of  this  system  most  be  influenced  to  produce  it  regularly. 

M.  Flourens  commenced  with  the  nerves,  and  fully  confirmed  the  views  usually  enter- 
tained respecting  their  functions.  He  has  shown,  in  a  satisfactory  manner,  «'  that,  hi 
order  to  effect  contraction,  a  free  and  continued  communication  is  requisite  between  the 
nerve  and  i.  I  that  to  produce  sensation,  a  similar  communication  with  the 

brain  is  equally  necessary.  '5-nce  1;?.  concludes,  that  neither  contraction  nor  sensation 
belong  to  the  nerve  ;  that  these  two  effect  ,'U  they  may  take  place  in- 

dependently of  each  other ;  and  that  these  propositions  hold  good,  at  whatever  pia't, 
and  in  whatever  branch  of  a  nerve  the  communication  is  interrupted. 

**  Employing  the  sante  method  with  regard  to  the  spinal  marrow,  he  arrived  at  similar 
conclusions.  When  it  is  irritated  in  any  given  point,  contractions  are  excited  in  all  the 
muscles  which  derive  their  nerves  from  below  this  point,  if  the  communication  remains 
free  but  not  if  the  communication  be  interrupted.  Exactly  the  reverse  obtains  with 
regard  to  sensation ;  and,  as  in  the  nerves,  the  government  of  the  will  requires  th« 
same  freedom  of  communication  as  sensation,  the  muscles  beneath  the  intercepted  part 
no  longer  obey  the  animal,  and  he  has  no  feeling  in  them  :  in  fine,  if  the  spinal  mar- 
row be  intercepted  at  two  points,  the  muscles  which  receive  their  nerves  from  this  in- 
terval experience  contractions  alone  ;  but  the  animal  does  not  command  them,  nor  receive 
from  them  any  sensation."  M.  F.  farther  inferred,  from  his  experiment  respecting  the 
functions  of  the  spinal  marrow,  that  sensation  and  contraction  belong  no  more  to  it 
than  to  the  nerves. 

He  next  directed  his  researches  to  the  brain,  in  order  to  ascertain  the  point  whence 
irritation  departed,  and  point  where  the  sensation  arrives,  and  to  determine  their 
respective  co-operation  in  acts  of  volition.  Advancing  from  the  medulla  oblongata 
towards  the  hemispheres,  Mr.  Flourens  first  examined  how  far  it  was  possible  to  go,  and 
still  produce  sufficient  irritation  on  the  muscular  system,  when  he  arrived  at  a  point 
where  these  irritations  disappeared  :  "  then  taking  the  brain  at  the  opposite  part,  he 
irritated  it  at  points  deeper  and  deeper,  as  long  as  he  did  not  act  upon  the  muscles ;  and 
when  he  did  begin  to  act  upon  them,  he  found  himself  at  the  same  point  where  the  ac- 
tion had  ceased  in  ascending.  This  part  is  -also  that  where  the  sensation  of  irritation  ap- 
plied to  the  nervous  system  likewise  ceases  :  above  this,  punctures  and  wounds  do  not 
excite  pain.  Thus  M.  Flourens  pricked  the  hemispheres  without  producing  contraction 
of  the  muscles,  nor  the  appearance  of  pain  in  the  animal ;  he  removed  them  in  successive 
slices  ;  he  did  the  same  with  regard  to  the  cerebellum  ;  he  removed  at  once  the  hemis- 
pheres and  cerebellum.  The  animal  remained  passive.  The  corpora  striata  and  the 
optic  thalanil  were  attacked,  and  removed  without  any  other  effect :  the  iris  was  not  con- 
tracted, nor  even  paralysed.  But  when  he  pricked  the  t-ubercula  quadrigemina,  trem- 
bling and  convulsions  began,  and  these  increased  in  proportion  as  he  penetrated  into 
the  medulla  oblongata.  Pricking  the  tubercles,  as  well  as  the  optic  nerve,  produced 
quick  and  continued  contraction  of  the  iris.  These  experiments  agree  with  those  of 
Lorry,  published  in  third  volumeof  the  '  Mgmoires  des  Savans  etnmgers.'  <  Neither  the 
irritation  of  the  brain,  nor  of  the  corpus  callosum  itself  produce  convulsions :  it  may  even 
be  removed  with  impunity.  The  only  part  among  those  contained  in  the  brain  which 
has  appeared  uniformly  and  universally  capable  of  exciting  convulsions,  is  the  medulla 
oblongata:  it  is  this  part  which  produces  them  to  the  exclusion  of  every  other.'  They 
contradict  the  experiments  of  Haller  and  Zinn  with  regard  to  the  cerebellum ;  but, 
from  what  M.  Flourens  has  sc>en  and  pointed  out,  it  appears  that  these  physiologists  had 
touched  the  medulla  without  being  aware  of  it.  He  concludes  that  the  medulla  oblon- 
gata and  the  tubercles  are  (in  his  language)  irritable  ;  which  means  that  they  are  con- 
ductors of  irritation,  like  the  spinal  marrow  and  nerves,  but  that  neither  the  cerebrum  nor 
cerebellum  possess  this  property.  The  author  hence  concludes,  likewise,  that  these 
tubercles  form  the  continuation  and  superior  termination  of  the  spinal  cord  and  medulla 
oblongata;  and  this  opinion  is  in  conformity  with  their  situation  and  anatomical  con- 
nexions. 

Wounds  of  the  brain  and  cerebellum  do  not  excite  pain  any  more  than  convulsions. 
Hence  M.  Flourens  infers  that  to  them,  the  impression  received  by  sensible  organs 
must  be  conveyed,  in  order  that  the  animal  may  experience  a  sensation.  He  appears 


70  APPENDIX. 

fto  have  established  this  proposition  in  a  satisfactory  manner,  with  regard  to  the  senses  of 
sight  and  hearing1;  tor  when  both  lobes  of  the  cerebrum  are  removed,  th«  animal  becomes 
both  blind  and  deaf.  « Instead  of  saying,  with  M.  Flourens,  that  the  cerebral  lobes 
are  the  only  organs  of  sensation,  we  should  restrict  ourselves  to  ascertain  facts,  and  con- 
tent ourselves  with  saying  that  these  lobes  are  the  sole  receptacle  where  the  senses  of 
sight  and  hearing  can  be  perfected,  and  become  perceptible  to  the  animal.  If  we 
wished  to  add  to  this,  we  should  say  that  they  are  likewise  those  where  all  the  sensa- 
tions take  a  distinct  form,  and  leave  durable  traces  on  the  memory, — that  they  serve,  in 
a  word,  as  the  seat  of  memory ;  a  property,  by  means  of  which  they  furnish  the  animal 
materials  for  judgment.  This  conclusion,  thus  reduced  to  proper  terms,  becomes  the 
more  probable,  in  that,  besides  the  veri-similitude  which  it  receives  from  the  structure 
of  these  lobes,  and  their  connexion  with  the  rest  of  the  system,  comparative  anatomy 
offers  another  confirmation  in  the  constant  relation  of  the  volume  of  these  lobes  with 
the  degree  of  intelligence  of  the  anmal." 

M.  Flourens  next  examined  the  effects  which  follow  the  extirpation  of  the  tubercnla 
quadrigemina.  "  The  removal  of  one  of  them,  after  a  convulsive  movement,  which 
soon  ceases,  produces,  a  permanent  result,  blindness  of  the  opposite  eye  and  involun- 
tary staggering  ;  that  of  both  tubercles  renders  the  blindness  complete,  and  the  stag- 
gering more,  violent  and  long-continued.  The  animal,  however,  retains  all  its  faculties 
und  the  iris  continues  contractile.  Tho  deep  extirpation  of  the  tubercle,  or  the  sec- 
tion of  the  optic  nerve  only,  paralyses  the  iris :  from  which  the  author  infers,  that 
the  the  removal  of  the  tubercle  only  acts  as  the  division  of  the  nerve  would  do ;  that 
this  tubercle  is  only  a  conductor  uith  regard  to  vision  ;  and  that  the  cerebral  lobe  alone 
Is  the  seat  of  the  sensation,  the  point  where  it  is  consummated,  and  passes  into  per- 
ception." 

M.  F.  next  investigated  the  functions  of  the  cerebellum,,  and  found  that,  during  the 
removal  of  the  first  layers,  "  there  appeared  only  a  slight  weakness  and  want  of  har- 
mony among  the  movements.  At  the  middle  layers,  a  disturbance  nearly  general  was 
manifested.  The  animal,  in  continuing  to  see  and  hear,  only  executed  quick  and  ir- 
regular movements  :  the  faculty  of  flying,  walking,  and  keeping  itself  standing,  were 
lost  by  degrees.  When  the  bra'in  was  cut  off,  this  faculty  of  performing  regulated  mo- 
tion had  entirely  disappeared.  Placed  upon  the  back,  he  did  not  rise  ;  but  continued 
to  see  the  blow  which  menaced  him  ;  he  heard  sounds,  and  endeavoured  to  shun  the 
danger  which  was  threatened  :  in  a  word,  feeling  and  volition  were  retained,  but  the 
power  over  the  muscles  was  lost;  scarcely  could  he  support  himself  with  the  assistance 
of  the  \yings  and  tail.  In  depriving  the  a'nimal  of  the  bruin,  it  was  thrown  into  a  state 
resembling  sleep  :  in  removing  the  cerebellum,  it  was  brought  to  a  state  resembling 
intoxication." 

The  reporters  to  the  Institute  on  the  inquiries  of  M.  Flourens,  have  drawn  the  fol- 
lowing conclusions  "  from  a  rigorous  examination  of  the  facts  which  he  has  establish- 
ed : — the  integrity  of  the  cerebral  lobes  is  necessary  to  the  exercise  of  sight  and  hear- 
ing :  when  they  are  removed,  the  will  no  longer  manifests  itself  by  voluntary  acts. 
However,  when  the  animal  is  immediately  excited,  he  performs  regular  movements,  as 
if  endeavouring  to  avoid  pain  or  inconvenience  ;  but  these  movements  do  not  effect  his 
purpose,  most  probably  because  the  memory,  which  has  been  removed  along  with  the 
lobes  which  constituted  its  seat,  no  longer  affords  grounds  or  elements  of  judgment : 
Ihese  movements  have  no  consistency,  for  the  same  reason,  that  the  impulse  which 
caused  them  neither  leaves  any  remembrance  nor  permanent  volition.  The  in- 
tegrity of  the  cerebellum  is  necessary  to  the  regularity  of  locomotion :  let  the  brain 
remain,  the  animal  will  see,  hear,  and  have  evident  and  powerful  volition  ;  but,  if  the 
cerebellum  be  removed,  he  will  never  find  the  balance  necessary  to  locomotion.  As 
to  the  rest,  irritability  remains  in  parts  without  the  brain  or  cerebellum  being  neces- 
sary. Every  irritation  of  a  nerve  brings  it  into  play,  in  muscles  to  which  it  is  distribut- 
ed :  every  irritation  of  the  spinal  marrow  excites  ft  in  all  members  beneath  the  point 
of  its  application.  It  is  quite  at  the  top  of  the  medulla  obhwgata,  at  the  point  where  the 
tubercula  quadrigemina  join  it,  that  this  faculty  of  receiving  and  propagating  irrita- 
taion  on  the  one  hand,  and  pain  on  the  other,  ceases.  It  is  this  point  at  which  sensa- 
tion must  arrive  in  order  to  be  perceived ;  it  is  from  hence  that  the  mandates  of  the 
will  must  emanate.  Thus,  the  continuity  of  the  nervous  organ  from  this  point  to  the 
different  parts  of  the  body  is  requisite  for  voluntary  motion,  and  for  the  perception  of 
impressions  whether  external  or  internal." 

Thus,  then,  the  property  of  nervous  irritability  or  of  receiving  and  conducting  sensa- 
tion and  irritation  is  limited  to  the  nerves,  spinal  cord,  medulla  oblongata,  and  corpora 
quadrigemina,  "  the  integrity  of  the  optic  thalami  is  not  essential  to  the  contractility 
of  the  iris  ;  the  sensations  of  light  and  of  sound  reside  in  th~  cere-bra!  lobes,  and  therv 


OF  THK  CEREBRO-SP1NAL  SYSTEM,  7| 

also  all  other  sensations  acquire  distinctness  and  durability;  the  spinal  cord  combines 
the  muscular, contractions  so  as  to  produce  motion  in  the  joints  ;  and  the  cerebellum 
regulates  these  movements,  and  unites  them  so  as  to  constitute  the  actions  of  standing- 
and  locomotion  :— such  are  the  discoveries  of  M.  Flourens*." 

III.  jQf  the  distinct  Functions  of  the  anterior  and  posterior  Columns  of  the  Spinal  Mar- 
row. It  is  certain  that  the  spinal  marrow  sends  oft'  nerves  engaged  in  the  performance 
of  two  distinct  functions,  viz.  that  of  feeling-  and  that  of  motion.  From  what  part — 
we  are  led  to  ask — of  this  organ,  do  the  nerves  allotted  to  each  of  these  functions  pro- 
ceed ?  It  is  well  known  that  the  spinal  marrow  is  formed  of  two  substances— a  white 
substance,  which  is  exterior,  and  a  gray  substance,  occupying  the  interior  of  the  cord, 
The  continuity  of  the  fibres  composing  the  roots  of  the  spinal  nerves  with  the  latter, 
as  established  by  Keuifel  and  Ollivier,  naturally  leads  us  to  suppose  that  it  is  particu- 
larly concerned  in  the  production  of  these  functions.  It  may  be  also  observed,  that 


*  Experiments,  similar  to  those  of  M.  Flourens  were  instituted,  in  1805,  by  profes- 
sor Rolando,  of  Turin,  from  which  he  deduced  inferences  in  some  respects  the  same 
as  those  at  which  M.  Flourens  has  arrived.  The  experiments  of  the  latter  physiologist 
were,  however,  more  varied,  were,  apparently,  more  carefully  performed,  and  there- 
fore were  more  conclusive,  than  those  of  his  predecessor.  They  were  repeated,  more- 
over, before  a  commission  of  the  institute  of  France,  composed  of  some  of  the  most 
eminent  of  that  body,  who  approved  of  the  conclusions  which  are  given  above.  The 
following  are  the  inferences  which  M.  Flourens  considers  that  his  experiments  justify. 

1.  "  No  movement  proceeds  immediately  from  the  will.     The  will  is  the  exciting  and 
determining  cause  of  certain  movements ;  but  it  is  never  the  efficient  or  effective  cause 
of  any. 

2.  "  It  has  been  shown  that  the  immediate  cause  of  muscular  contraction,  particu- 
larly resides  in  the  spinal  marrow  and  nerves,  and  that  the  regulating  cause  of  these 
contractions  is  placed  in  the  cerebellum. 

3.  "  There  are,  therefore,  three  phenomena  essentially  distinct  in  a  movement  pro- 
ceeding from  volition  :  1,  the  volition  of  movement,  a  volition  which  seems  to  reside  in 
the  cerebral  hemispheres  :  2,  the  appropriate  regulation  of  the  different  muscular  con- 
tractions productive  of  motion,  which  reside  in  the  cerebellum :  and  3,  the  excitation 
of  these  contractions,  which  has  its  efficient  seat  in  the  spinal  marrow  and  its  nerves. 

4.  "As  these  three  phenomena,  essentially  distinct,  reside  in  three  organs  also  dis- 
tinct, the  possibility  of  abolishing  any  one  of  them,  and  leaving  the  others  uninjured, 
seems  apparent ;  thus  the  will  may  be  destroyed,  and  the  regulation  of  contraction  it- 
self will  remain :  or  both  volition  and  the  regulating  cause  of  contraction  may  be 
abolished,  and  contraction  will  alone  be  produced,  &c. 

5.  "  There  exists,  therefore,  in  the  nervous  system,  (cerebro-spinal  system,)  three 
properties  essentially  different :  one,  the  exciter  of  motion  ;  the  other  the  regulator  / 
and  the  third,  the  -wilier  and  perceiver. 

6.  "The  spinal  marrow,  the  medulla  oblongata,  the  tubercula  quadrigemina,  alone 
possess  the  property  of  directly  exciting  muscular  contraction ;  the  cerebral  lobes  and 
cerebellum  do  not  possess  it. 

7.  "  There  are  two  ways  of  destroying  vision  without  g'oing  beyond  the  cerebral 
mass  :  one  by  the  removal  of  the  tubercula  quadrigemina — producing  loss  of  the  sense 
of  sight,  the  other,  by  the  removal  of  the  cerebral  lobes, — causing  the  loss  of  the  sen- 
sation of  sight. 

8.  "  There  is,  therefore,  in  the  cerebral  mass,  distinct  organs  for  the  senses,  for.the 
sensations -,  for  the  movements. 

9.  *'  Not  only  all  the  sensations,  all  the  perceptions,  all  the  volitions,  all  the  intellec- 
tual and  sensitive  faculties  reside  exclusively  in  the  cerebral  lobes,  but  all  these  facul- 
ties occupy  jointly  the  same  seat  in  these  organs  ;  for  if  one  of  them  disappear,  all 
disappear ;  and  if  one  return,  all  return.     The  power  of  feeling,   willing,  and  per- 
ceiving constitute  therefore  but  one  faculty,  residing  but  in  one  organ. 

10.  "  The  cerebral  lobes,  the  cerebellum,  the  tubercula  quadrigemina,  may  lose  a 
considerable,  bat  limited,    portion  of  their  substance,  without  losing  the  exercise  of 
their  functions  ;  and  they  may  re-acquire  them  after  being  totally  deprived  of  them. 

11.  "  The  spinal  marrow  and  the  medulla  oblongata,  are  the  only  parts  which  directly 
affect  the  same  side  of  the  body,   with  that  in  which  they  are  themselves  aifected. 
The  tubercula  quadrigemina,   the  cerebral  lobes,  and  the  cerebellum  alone  produce 
their  effects  upon  the  opposite  side  to  that  in  which  they  are  influenced  ; — the  former 
act  in  a  direct  course,  the  latter  in  a  cross  direction." 


72  APPENDIX. 

the  fibres  of  the  anterior  roots  are  much  smaller  than  those  of  the  posteriory—a  ch*-» 
cumstance  which,  when  viewed  in  connexion  with  what  has  been  advanced  on  the  sub* 
ject  by  Mr.  Charles  Bell*  and  M.  Magendie  shows  that  each  set  of  fibres  (posterior  and 
anterior)  is  more  immediately  allotted  to  the  performance  of  a  distinct  function, — that 
the  posterior  roots  are  devoted  to  the  sensibility  'of  the  parts  which  these  nerves  sup- 
ply, and  the  anterior  to  the  muscular  contractions.  But  it  appears,  from  the  experi- 
ments of  M.  Magendie,  .that  one  of  these  functions  does  not  exclusively  belong1  to  one 
order  of  these  roots  ;  for,  when  the  posterior  roots,  or  those  which  more  particularly 
belong1  to  sensibility",  are  irritated,  contractions  are  occasioned  in  the  muscles  to  which 
their  nerves  are  distributed,  although  the  contractions  are  much  more  strong  and  much 
more  complete  when  the  irritation  is  directly  applied  to  the  anterior  roots  of  the  nerves. 
Slight  appearances  of  sensibility  are  also  occasioned  when  irritation  is  made  on  the  an- 
terior roots.  It  must  therefore  be  concluded,  that  sensibility,  although  chiefly,  is  not 
exclusively,  in  the  posterior  roots,  nor  motion  in  the  anterior. 

This  defect  of  complete  isolation  of  these  two  functions  may  arise,  as  M.  Ollivier 
supposes,  from  the  gray  matter  of  each  lateral  half  of  the  marrow,  which  seems  to  be 
concerned  in  their  production,  being  entirely  confounded  at  their  central  points  of 
contact ;  and  from  the  intimate  union  which  takes  place  between  both  the  roots,  be- 
low the  spinal  enlargement  (intervertebral  ganglions)  and  which  must  contribute  still 
farther  to  combine  these  functions  so  as  to  prevent  their  perfect  separation. 

It  should  be  recollected  that  the  functions  ought  not  to  be  attributed  to  the  roots  of 
the  nerves  themselves.  M.  Magendie  found,  that  when  these  nerves  were  divided  close 
to  the  marrow,  and  irritation  then  made  on  their  roots,  no  sensible  effect  followed  : 
whereas,  while  their  connexion  with  the  marrow  was  preserved,  the  slightest  irritation 
was  productive  of  effect ;  and  the  nearer  that  it  was  made  to  the  spinal  cord,  the  more 
intense  was  the  influence  occasioned  by  it.  Hence  it  follows  that  the  gray  substance 
of  the  cord,  whence  arise  the  roots  of  the  spinal  nerves,  is  much  more  intimately  con- 
cerned in  the  production  of  the  operations  in  question  than  the  roots  of  the  nerves 
themselves ;  but  this  substance  itself  seems  to  depend  more  upon  the  differts  parts 
composing  the  encephalic  mass,  for  whatever  influence  it  may  exert  in  the  production 
of  the  phenomena  under  consideration,  than  M.  Ollivier  appears  to  allow.  He  attri- 
butes them  both  almost  exclusively  to  the  gray  substance  of  the  centre  of  the  cord, 
which  he  considers  to  be  voluminous  in  proportion  as  these  faculties  are  developed. 
This  part  of  the  cord,  although  altogether  necessary  to,  and  instrumental  in,  their  pro- 
duction, can  only  be  viewed  as  one  of  three  distinct  classes  of  structure,  each  of  which, 
as  M.  Flourens  has  stated,  performs  distinct  actions,  which  by  their  combination,  con- 
stitute but  an  individual  function,  that  could  not  result  from  any  one  or  two  only  of  the 
actions  composing1  it,  but  is  the  consequence  of  a  more  or  less  perfect  co-operation  of 
the  whole*. 


*  Mr.   Bell's  attention  was  attracted  by  "  the  difference  in  the  distribution  of  the 
nerves  of  the  head  from  those  of  the  body,  and  the  fact  that  all  the  spinal  nerves  arise 
by  double  roots.     Observing  that  this  form  of  origin  was  the  same  in  all  animals  pos- 
sessing a  spinal  cord,  and  considering  that  the  anterior  column  of  the  spinal  marrow 
was  continuous  with  the  crura  of  the  cerebrum,  and  the  posterior  with  the  crura  of 
the  cerebellum, — he  conceived  that  by  experiments  on  the  roots  of  these  nerves, 
he  might  discover  the  functions  of  the  the  two  columns,  and,  perhaps,    through 
them,   arrive  at  a  more  accurate  knowledg  of  the  relations  and  individual  uses  of 
the  cerebrum  and  cerebellum."    Previously,  however,  to  these  experiments,  Mr. 
Bell   entertained  the  opinion  that  the  anterior  column  of  the  spinal  cord  was  dif- 
ferent in  function  from  the   posterior;   and  that,  through  the  former,   the  simple 
voluntary  power  of  moving  particular  parts  was  conveyed.     He  deduced  this  from 
observing,  that  the  two  nerves,  which  are  generally  supposed  to  be  purely  motors, 
arise  from  the  anterior  fasciculus.     The  experiments  which  these   opinions  suggested, 
although  they  were  not  conclusive,  yet  encouraged  the  view  he  had  taken,  and  gave 
results  in  some  degree  similar  to  those  which  Magendie  subsequently  obtained  from 
his  experiments.     To  Mr.  Bell,  therefore,  the  honour  of  having  originated  these  views 
clearly  belongs. 

*  Of  the  distinct  functions  of  the  cerebellum,  numerous  opinions  have  been  lately  en- 
tertained.    Dr.  Gall  considers  it  to  be  the  seat  of  physical  love.     Mr.  Rolando,  who 
adopts  the  opinion  of  a  nervous  fluid,  which  he  regards  as  analogous  to  the  galvanic 
fluid,  places  the  source  and  seat  of  the  principle  of  muscular  contraction  in  the  cere- 
bellum, which,  owing  to  the  disposition  of  its  laminated  convolutions,  he  considers  to 


OF  THE  RESPIRATORY  ORDER  OF  NERVES.  73 

IV.  Of  the  Respiratory  Order  of  Ncnvs. — All  animals  that  possess  a  perfect  cerebrn- 
•spinal  system  have  an  intermediate  order  of  nerves  which  connect  the  vegetative  func- 
tions of  the  ganglial  system  with  the  functions  of  the  encephalon.  This  order  of  nerves 
has  lately  been  very  satisfactorily  examined  into,  both  as  respects  their  distribution  and 
functions  by  Mr.  Charles  Bell. 

On  investigating-  the  minute  structure  of  the  nerves  whi«h,  both  in  man  and  in  the 
lower  animals,  arise  from  the  spinal  marrow  by  double  roots,  and  those  which  proceed 
from  the  medulla  oblongata,  by  single  origins,  to  the  organs  of  respiration  and  those 
parts  of  the  face  and  trunk  which  evince  an  intimate  relation  with  this  important  func- 
tion, Mr.  Bell  perceived  their  texture  and  mode  of  distribution  were  very  different. 
This  circumstance  led  him  to  consider  that  two  distinct  orders  of  nerves  must  exist  in- 
dependently of  the  sympathetic,  the  one  simple  and  uniform,  the  other  irregular  and 
complex  in  proportion  to  the  complexity  of  the  organization.  The  former  he  has  called 
original  or  symmetrical,  the  latter  supcradded  or  irregular.  In  the  superadded  class  of 
nerves,  which  are  chiefly  devoted  to  the  function  of  respiration,  Mr.  Bell  arranges,  1st, 
the  par  vagum  ;  2d,  the  portio  dura ;  3d,  the  spinal  accessory  ;  4th,  the  phrenic  ;  5th, 
the  external  respiratory  nerves,  &c.  "  The  nerves,'*  this  Physiologist  states,  "  on  which 
the  associated  actions  of  respiration  depend,  and  which  have  been  proved  to  belong  to 
this  system,  by  direct  experiment,  and  the  induction  from  anatomy,  arise  very  nearly 
together.  Their  origins  are  not  in  a  bundle,  or  fasciculus,  but  in  a  line  or  series,  and 
from  a  distinct  column  of  the  spinal  marrow.  Behind  the  corpus  olivare,  and  anterior  to 
that  process  which  descends  from  the  cerebellum,  the  corpus  retiforme,  a  convex  slip  of 
medullary  matter,  may  be  observed ;  and  this  convexity,  or  fasciculus,  or  virga,  may  be 
traced  down  the  spinal  marrow,  betwixt  the  sulci,  which  give  rise  to  the  anterior  and 
posterior  roots  of  the  spinal  nerves.  This  portion  of  medullary  matter  is  narrow  above 
where  the  pans  varoUi  overhangs  it.  It  expands  as  it  descends  ;  opposite  to  the  lower 
part  of  the  corpus  oli-vare  it  has  reached  its  utmost  convexity,  after  which  it  contracts  a 
iittle,  and  is  continued  down  the  lateral  parts  of  the  spinal  marrow." 

From  this  tract  of  medullary  matter  on  the  side  of  the  medulla  oblongata,  arise  in 
succession  from  above  downwards  the  portio  dura,  the  glosso-pharyngeus,  the  par  vagum t 
the  nervus  accessorius,  the  phrenic,  and  the  external  resfriratory.  These  superadded 
nerves  are  comparatively  but  little  sensible  ;  they  do  not  arise  by  double  roots,  as  the 
symmetrical  do  :  and  they  have  no  ganglia  on  their  origins,  and  while  the  other  volun- 
tary nerves  have  large,  free,  and  round  filaments,  they  have  a  close,  loose  texture,  re- 
sembling a  minute  plexus.  "  These  are  the  nerves  which  give  the  appearance  of  con- 
iusion  to  the  dissection,  because  they  cross  the  others,  and  go  to  parts  already  plenti- 
i'ully  supplied  from  the  symmetrical  system." 

From  these  anatomical  investigations,  and  from  experiments  made  in  order  to  ascer- 
tain the  exact  functions  of  this  order  of  nerves,  Mr.  C.  Bell  and  Mr.  Shaw  have  drawn 
some  important  inferences ; — 1st,  They  consider  that  the  portio  dura  of  the  seventh 
pair  "  produces  all  those  motions  of  the  nostrils,  lips,  or  face  generally,  which  accord 
•with  the  motions  of  the  chest  in  respiration.  When  cut,  the  face  is  deprived  of  its  con- 
sent with  the  lungs,  and  all  expression  of  emotion.  2d,  The  par  vagum  associates  the 
larynx,  the  lungs,  the  heart,  and  the  stomach  with  the  muscular  apparatus  of  respira- 
tion. 3d.  The  spinal  accessory  controls  and  directs  the  operations  of  the  muscles  of 
the  neck  and  shoulder,  in  the  offices  of  respiration.  4th,  The  phrenic  nerve  has  its 
functions  sufficiently  characterized  in  the  name  of  internal  respiratory,  which  Mr.  Bell 
has  assigned  it.  5th,  The  glossopharyngeal  nerve,  &c.  ;  and,  6th,  the  external  respira- 
tory nerve,  perform  the  functions  which  those  parts,  to  which  they  are  distributed, 
have  in  connexion  with  the  operations  of  respiration. 


act  in  the  manner  of  a  voltaic  pile,  and  to  transmit,  under  the  direction  of  the  brain, 
and  through  the  channel  of  the  spinal  cord  and  nerves,  the  moving  principle  to  the 
muscles.  Mr.  Flourens,  as  we  have  shown,  views  this  organ  as  the  regulator  and  ba- 
lancer of  the  muscular  contractions.  M.  Magendie  regards  it  as  requisite  to  the  pro- 
iluction  of  motion  forwards  :  and  Mr.  C.  Bell,  Messrs.  Fodera,  Foville,  and  Pin  el- Grand - 
champ  are  of  opinion,  that  it  is  the  seat  of  sensibility. 

K 


APPENDIX. 


Of  the  Faculties  of  the  Mind,  as  evinced  through  the  instrumentality  of  a  perfect 

Nervous  System. 

Note  EE. 

This  very  extensive  subject  can  only  receive  a  very  cursory  notice  from  us  at  this 
place.  We  shall  merely  offer  an  arrangement  of  the  powers  of  the  mind,  commencing- 
with  its  lowest  manifestations,  or  those  most  extensively  disseminated  throughout  the 
animal  kingdom,  and  proceeding  to  the  highest  or  most  perfect  faculties. 

CLASS  I.  INSTINCTIVE  POWERS. — (Strong  and  immediate  incentives  to  Action.) 
ORDJER  I.     Instinctive  Powers  -which  tend  to  preserve  the  Individual. 

1,  The  appetite  for  food  and  drink.     2.  The  desire  of  pre. 
serving  the  animal  warmth.     3,   The  desire  of  repose. 
4,  Desire  of  place. 
ORDER  II.     Instinctive  Powers  -which  tend  to  perpetuate  the  species. 

1,  The  appetite  for  procreation.  2,  Parental  and  filial  af- 
fection. 3,  Desire  of  society.  4,  Social  affection,  giv- 
ing rise  to  mutual  support.  *  5,  Sympathy. 

CLASS  II.  INTELLECTUAL  POWERS. 

ORDER  I.     Powers  of  consciousness,  or  the  simpler  Manifestations  of  Mind. 

1,  Perception.     2,  Attention.    3,  Memory.    4,  Conception, 
OIIBER  II.     Powers  of  Intellection,  or  the  more  Active  Powers  of  Mind. 

1,  Association  of  Ideas.     2,  Abstraction.     3,  Imagination. 

4,  Judgment  or  Reasoning. 
OBDEB  III.     Ideas  of  Reflection,  springing  from  the  Exercise  of  the  former 

Orders  of  Powers.     (Rational  incentives  to  Action. ) 
1,  Personality.     2,    Time.     3,  Power.    4,   Truth,  Causa* 
tion.    5,  Existence  of  a  Deity.     6,  Duty,  Moral  and 
Religious  obligations,  Rectitude,  Merit  and  Demerit,  &c. 

It  will  be  perceived  that  the  third  order  of  ideas,  into  which  we  have  arranged  here 
the  intellectual  powers,  are  chiefly  derived  from  reflection,  or  from  the  mind  itself. — Se? 
on  this  subject  the  writings  of  Duff  aid  Steward ;  of  Doctor  Brown  ;  Dr.  Barclay,  on  Life 
and  Organization ,-  Dr.  Pritchard  on  the  Nervous  System ,-  and  the  London  Medical  Re*. 
positorii,  volumes  xvii.  and  xviii. 


Of  Dreaming. — Mr.  A.  Carmichael  has  lately  adopted  and  illustrated  the  theory  ot 
dreaming  proposed  by  Dr.  Spurzheim,  that  dreams  are  caused  by  certain  isolated  por- 
tions or  organs  of  the  brain  continuing  awake,  while  the  remainder  of  it  is  in  a  temporary 
paralysis  from  sleep.  "  According  to  this  view  the  particular  dream  will  be  fashioned 
by  the  part  or  parts  which  are  not  under  the  dominion  of  sleep ;  and  the  irrationality  of 
our  sleeping  thoughts  is  accounted  for  by  one  or  more  parts  or  organs,  thus  acting  with- 
out co-operation  or  correction  from  the  other  parts  of  the  encephalon." 

Mr.  C.  enumerates  no  less  than  seven  different  states  of  sleeping  and  waking  '.—  When 
the  entire  brain  and  nervous  system  are  buried  in  sleep,  then  there  is  a  total  exemption 
from  dreaming.  2,  When  some  of  the  mental  organs  are  awake,  and  all  the  senses  are 
asleep  ;  then  dreams  occur,  and  seem  to  be  realities.  3,  When  the  above  condition 
exists,  and  the  nerves  of  voluntary  motion  are  also  in  a  state  of  wakefulness  ;  then  may 
occur  the  rare  phenomenon  of  somnambulism.  4,  When  one  of  the  senses  is  awake, 
with  some  of  the  mental  organs ;  then  we  may  be  conscious,  during  our  dream,  of  its  illu- 
sory nature.  5,  When  some  of  the  mental  organs  are  asleep,  and  two  or  more  senses  awake  ; 
then  we  can  attend  to  external  impressions,  and  notice  the  gradual  departure  of  our 
slumbers.  6,  When  we  are  totally  awake,  and  in  full  possession  of  our  faculties  and 
powers.  7,  When,  under  these  circumstances,  we  are  so  occupied  with  mental  opera- 
tions, as  not  to  attend  to  the  impressions  of  external  objects  /  and  then  our  re  very  deludes 
us  like  a  dream. 


OF  THE  MUSCULAR  STRUCTURE.  75 

Of  the  Formation  and  development  of  the  Muscular  Structure,  and  of  the 
Source  of  Irritability. 

Note  F.F. 

In  the  very  lowest  orders  of  animals  a  muscular  structure  does  not  exist  in  a  distinct 
state.  Their  partial  movements  are  performed  by  means  of  the  cellular  tissue  of  wliich 
they  are  composed.  In  the  lowest  of  the  series  possessing-  a  muscular  texture,  it  moves 
only  the  integuments  to  which  it  is  attachedj  and  of  which  it  even  forms  a  part.  In  all 
animals  possessed  of  a  heart,  the  muscular  tissues  constitues  an  important  part.  In  all 
the  vertebrated  animals  a  small  number  only  of  the  muscles  are  attached  to  the  mucous 
surfaces,  to  the  skin  and  its  appendages  ;  whilst  the  greatest  proportion  is  connected 
with  the  skeleton  for  the  purposes  of  progression. 

According  to  the  researches  of  Dr.  Isenflamm,  of  Dorpat,  into  the  progressive  de- 
velopment of  the  muscular  structure  in  the  human  foetus,  this  tissue  is  formed  from  the 
mucous  and  gelatinous  fluid  of  which  the  embryo  is  at  first  composed; 

From  this  mucous  fluid  the  involutary  muscles  are  at  first  developed,  and  afterwards 
the  voluntary.  During  the  first  three  months  the  voluntary  muscles  present  the  ap- 
pearance of  viscous  layers,  with  a  slight  yellowish  tint.  At  the  end  of  the  third  month 
the  tendons  make  their  appearance.  During  the  fourth  and  fifth  months  the  muscles 
become  redder,  more  fibrous,  and  more  easily  to  be  distinguished  from  their  tendons. 
In  the  sixth  month,  although  very  soft,  they  are  still  more  perfect.  At  the  full  term 
of  utero-gestation  the  muscles  are  formed,  but  they  are  pale,  yet  vascular ;  they  are 
soft,  and  their  bulk  much  greater  in  proportion  to  the  tendinous  and  aponeurotic  sub- 
stances than  in  the  adult. 

As  age  advances,  the  voluntary  muscles  become  redder  and  more  fuUy  developed, 
and  towards  the  decline  of  life,  more  rigid,  less  capable  of  quick  and  extensive  contrac- 
tion, and  comparatively  of  less  bulk  than  their  aponeurotic  and  tendinous  connexions. 


The  microscopic  observations  of  M.  Bauer,  Sir  Everard  Home,  Messrs.  Prevost,  Du- 
mas, and  Beclard,  seem  to  prove  that  the  ultimate  muscular  fibre  is  composed  of  cor- 
puscles (arranged  like  a  string  of  beads)  in  every  respect  similar  to  those  in  the  cen- 
tre of  the  red  globules  of  the  blood.  However,  to  obtain  a  correct  idea  of  the  ultimate 
conformation  of  the  muscular  fibre,  researches  ought  to  be  made  with  this  view  on  the 
raw  and  unprepared  muscle :  for  the  action  of  heat,  of  alcohol  and  acids,  evidently 
produces  changes  in  the  fibre,  and  coagulates  the  albumen,  which  enters  into  its  com- 
position. 

The  voluntary  nerves  dip  into  the  texture  of  the  voluntary  muscles  at  different  points, 
and  divide  into  numerous  minute  fibrils,  which  abruptly  escape  demonstration.  This 
sudden  manner  of  disappearing  is  owing  to  the  extreme  fibrils  having  become  sol'. 
and  diaphanous,  and  deprived  of  their  proper  envelopes,  so  that  their  medullary  sub- 
stance is  diffused,  as  it  were,  into  the  mucous  tissue,  connecting  the  muscular  fibres. 

The  cerebro-spinal  nerves,  although  they  are  numerous  and  large  in  the  voluntary 
muscles,  disappear  in  the  manner  just  pointed  out,  long  before  their  divisions  be- 
come sufficiently  numerous  to  be  distributed  to  each  muscular  fibre.  This  being  the 
case,  how  can  the  action  of  these  nerves  on  all  the  fibres  be  explained  ?  They  cannot 
be  the  direct  cause  of  the  muscular  contraction,  but  must  act  in  producing  it  through 
the  medium  of  another  and  a  more  general  conformation*  What  this  formation  appear.! 
to  us  to  be,  we  will  now  endeavour  briefly  to  show. 

It  has  been  stated  that  all  the  involuntary  muscles  are  supplied  with  the  ganglu-.l  o: 
soft  nerves  only  ; — that  they  surround  the  arteries  throughout  their  ramifications,  an  ' 
consequently  are  thus  present  in  the  voluntary  muscles  and  in  all  vascular  parts  ; — tl:a 
the  voluntary  nerves  themselves,  whether  we  trace  the  process  of  their  formation  in  the 
human  embryo,  or  observe  them  in  the  lower  orders  of  animals,  seem  to  originate  from 
the  ganglial,  the  cerebro-spinal  masses  being  the  perfectien  of  the  nervous  conforma- 
tion, and  the  last  part  of  it  which  becomes  completely  developed, — and  that  the  cere- 
bro-spinal nerves  are  destined  to  the  performance  of  functions  distinct  from  those  to 
which  the  other  and  more  generally  diffused  class  is  alloted.  As  irritability  is  present 
in  parts  which  do  not  receive  voluntary  nerves,  and  in  animals  which  do  not  possess 


this  part  of  the  nervous  sytem,  this  property  cannot  be  attributed  to  it.     To  wha't  other 
species  of  organization  can  we  refer  this  property  ?  We  find  it,  in  the  r 


the  more  perfect  an!- 


70  APPENDIX. 

mals,  chiefly  displayed  by  the  muscular  structure.  Is  it  from  this  circumstance,  an  at' 
tribute  of  muscular  parts,  and  the  pure  result  of  their  confirmation  ?  One  class  of  physio^ 
legists  answer  this  question  in  the  affirmative.  But  irritability  has  been  displayed  by 
the  lowest  orders  of  the  animal  creation,  wherein  a  muscular  structure  could  not  be  de- 
tected, even  in  the  parts  themselves  which  furnished  the  phenomenon,  therefore,  al- 
though a  property  of  the  muscular  fibre  it  is  neither  altogether  restricted  to  it,  nor  is  it 
strictly  the  result  of  the  organization  of  the  fibre  itself.  We  must,  consequently,  refer 
this  property  to  a  conformation  still  more  general  than  the  muscular  tissue,  both  as  re- 
spects the  whole  scale  of  the  animal  creation  and  the  organization  of  individual  spe- 
cies; allowing  at  the  same  time,  that  a  particular  structure  is  requisite  to  the  full  and: 
perfect  development  of  this  property,  but  that  this  structure  depends  upon  a  different 
source  from  itself  for  the  property  which  it  displays. 

Having  arrived  at  the  conclusion  that  irritability,  although  a  property  of  muscular 
parts,  is  not  the  result  of  muscular  organization,  but  is  derived  from  a" different,  and 
more  general  system,  supplying  the  muscular  structure  as  well  as  other  structures,  we 
must  next  inquire  what  this  system  is.  It  has  been  already  inferred,  from  various  con- 
siderations, that  the  ganglial  class  of  nerves  is  distributed  in  different  proportions,  to 
the  various  textures  and  organs  of  the  body  ;  that  these  nerves  are  similarly  distributed 
throughout  all  the  individuals  composing  the  animal  kingdom  ;  that  in  some  of  its  or- 
ders they  constitute  the  only  nervous  system  which  the  animal  possesses :  it  has  also  been 
demonstrated  that  this  class  of  nerves,  in  a  more  or  less  perfect  state  of  organization,  is 
present  wherever  irritability  is  manifested ;  that  these  nerves  are  the  most  generally 
diffused  of  any  the  animal  tissues  ;  that  no  other  structure  exists  but  this  which  can  be 
shown  to  be  present  in  every  species  of  irritable  parts,  in  all  orders  of  animals ;  and, 
consequently,  that  to  no  other  source  but  this  cun  the  property  of  irritability  be  as- 
signed. 

Having  inferred  that  the  muscular  fibre  is  only  the  instrument  of  contraction,  in  its 
more  perfect  condition, — that  it  performs  this  function,  in  consequence  of  a  certain  con- 
formation, und  owing  to  that  conformation  being  endowed  by  means  of  another  still 
more  generally  diffused  than  itself, — and  that  this  property  is  derived  from  the  ganglial 
or  soft  nerves  which  proceeds  either  directly  or  as  an  envelope  to  the  arteries,  to  all  the 
tissues  of  the  body — we  are  led  farther  to  infer  that  the  cerebro-spinal  nerves  are  dis- 
tributed to  muscular  parts  for  specific  purposes,  but  that  these  parts  do  not  derive  their 
innate  properties  from  these  latter  nerves — these  nerves  merely  excite  them,  or  rather 
are  conductors  of  a  stimulus  acting  on  properties  which  proceed  from  a  different  source. 
We  have  contended  that  these  properties  are  not  innate,  or  the  consequence  of  the 
conformation  of  the  muscular  fibre  itself;  but  are  derived  from  a  confirmation  still  more 
general,  which  surrounds^  or  is  otherwise  connected  with,  the  muscular  fibrils,    and 
that  this  more  general  conformation-  is  the  ramifications  of  the  ganglial  class  of  nerves. 
Conceiving,  therefore,  that  these  nerves  in  their  state  of  ultimate  distribution  and  dis- 
semination in  the  texture  of  the  muscle,  whether  in  the  form  of  unarranged  globules, 
or  of  minute  and  variously  arranged  fibrils  resulting  from  the  regular  distribution  of 
these  globules,  are  the  chief  source  of  the  property  evinced  by  muscular  parts  of  every 
denomination,  we  further  conclude  that  the  voluntary  or  cerebro-spinal  nerves  do  not 
produce  their  specific  effects  on  the  muscular  fibres, 'owing  to  a  nervous  fibril  being 
ramified  to  each  muscular  fibril,  for  this  does  not  take  place ;  nor.  do  these  effects 
proceed  from  the  direct  influence  ef  these  nerves  upon  the  muscular  fibril,  for  the 
muscular  fibre  derives  its  property  or  faculty  of  contraction  from  a  source  different  from 
itself,  and  from  the  voluntary  nerves  which  occasionally  excite  its  contractions ;  but 
that  these  nerves  seem  to  act  directly  upon  the  ultimate  distribution  of  the  ganglial 
nerves  of  the  muscle,  which  latter  nerves  bestow  on  it  the  faculty  of,  or  the  disposition 
to  active  contraction,  on  the  application  of  a  stimulus,  which  faculty  all  muscular  parts 
possess — the  former  class  of  nerves  conveying  to  some  of  these  parts  only  the  natural 
stimulus  which  induces  contraction,  or  which  excites  the  active  exertion  of  this  faculty 
bestowed  on  these  parts  from  a  different  source,  namely,  from  the  glangial  system.  The 
mode  of  termination  which  the  voluntary  nerves  observe  in  muscular  parts,  also  favours 
the  opinion  which  we  have  now  given.     These  nerves  terminate,  as  we  have  already 
noticed,  in  such  a  manner  as  kads  us  to  inter,  that  they  become,  in  a  manner  gradually 
indentified  or  amalgamated,  in  the  textures  which  they  supply,  with  the  ultimate  distri- 
butions of  the  ganglial  nerves  :  and  the  history  of  the  embryo,  and  the  progressive  ner- 
vous development  of  the  lower  animals,  would  dispose  us  to  believe  that  the  voluntary 
nerves  originate  in  the  textures  to  which  they  are  ramified,  from  the  ganglial  system, 
and  that  the  larger  branches  of  these  nerves,  the  spinal  marrow,  and  encephalon  are 
succc  '^s:  \v j Y  formed. 


oF  GALVANIC  ELECTRICITY  77 

Of  Galvanic  Electricity. 
Note  GG. 

The  phenomena  of  electricity  have  been  long-  known  to  philosophers  :  but  science 
has  been  chiefly  indebted,  in  our  own  times,  to  the  researches  oi  Davy,  Wollaston, 
IJiot,  Coulomb,  Poisson,  Oersted,  and  Becquerel,  for  a  knowledge  of  the  laws  by  which  it 
is  characterized.  The  observations  and  experiments  of  these  successful  inquirers  ap- 
pear fully  to  warrant  the  conclusion,  that  this  very  active  agent  of  nature  results  from 
two  distinct  fluids  universally  diffused  through  every  species  of  matter.  During  their 
circulation,  in  their  electro-motive  capacity,  through  the  corpuscles  of  matter  forming 
the  crust  of  this  planet,  they  accumulate  in  their  free  and  uncombined  state  upon  its 
external  surface,  in  consequence  of  the  imperfectly  conducting  property  of  the  enve- 
loping- atmosphere. 

The  electricities  "  are  thus  confined  on  the  superficies  of  the  globe,  and  indeed  of 
all  bodies  placed  on  its  exterior,  not  merely  be  the  non-conducting  faculty  of  the  air, 


and 

ae'rial  particles  rendered  fewer  in  number,  and  in  other  favourable  circumstances  of  the 
atmosphere,  as  in  its  humid  state,  the  electric  power  emanates  with  rapidity  from  the 
the  electrized  ball. 

Such  is  the  mode  of  existence  of  this  fluid  upon  the  surface  of  the  earth.  But  there 
also  exists  a  continual  condensation  of  the  electrical  agencies  in  the  substance  of  the 
different  matters  composing  the  crust  of  this  planet ;  and  the  galvanic,  chemical,  and 
other  phenomena,  clearly  show  that  although  such  condension  of  the  electricities  takes 
place  under  particular  circumstances  of  matter  yet,  a  continuous  circulation  of  it  is  also 
evident  under  other  relations.  This,  indeed,  is  observed  to  occur  during  every  manifes- 
tation of  the  galvanic  influence. 

Such  then  being  the  case,  and  as  it  is  now  generally  believed  that  the  circulation  of 
the  electricities  through  the  atoms  of  matter,  or  the  electro-motive  state,  as  it  has  with 
propriety  been  called,  gives  rise  to  the  phenomena  of  galvanism,*  which,  within  these 
few  years,  has  lead  to  the  most  splendid  discoveries  in  the  physical  world,  is  it  not  rea- 
sonable to  suppose  that  similar  operations  to  those  with  which  galvanic  experiments 
make  us  acquainted,  are  continually  taking  place  in  the  elements  of  nature  ?  As  it  has 
been  shown  that  every  species  of  matter  possesses  a  certain  proportion  of  the  electri- 
cities, may  it  not  be  allowed  that  under  circumstances  similar  to  those  with  which  ex- 
periment and  observation  make  us  acquainted,  a  continuous  current  of  the  different 
electricities  are  produced,  the  rapidity  and  sensible  effects  of  which  vary  according  to 
the  accidental  disposition  and  situation  of  the  different  material  bodies,  and  their  natu- 
ral states  of  electricity.  This  opinion  is  calculated  to  account  for  many  of  the  changes 
which  are  continually  taking  place  on  the  face  of  our  globe,  and  although  many  may 
not  feel  inclined  to  consider  these  fluids  as  the  chief  agents,  no  one  can  deny  them  a 
share  in  producing  the  effects  which  are  so  frequently  observed  upon  its  surface. 

The  laws  of  electricity,  whether  they  have  been  observed  in  connexion  with  its  free 
and  uncombined  state,  or  in  its  form  of  continouous  circulation,  as  displayed  in  the 


*  The  galvanic,  or  electro-motive  apparatus  may  be  considered,  ««  as  producing,  by 
the  mutual  contact  of  the  heterogeneous  bodies  w'hich  composed  it,  a  development  of 
electricity,  which  is  propagated  and  distributed  through  its  interior,  by  means  of  the 
conductors  interposed  between  its  metallic  elements  (plates.)  If  we  form  a  communi- 
cation between  its  two  poles,  the  discharge  xvhich  follows, overturning  the  state  of  elec- 
trical equilibrium,  in  the  series  of  bodies  super-imposed  on  each  other,"  (and  forming 
the  voltaic  pile,)  "causes  them  to  be  recharged,  according  to  the  conditions  of  this 
equilibrium,  either  at  the  expence  of  the  ground,  or  by  the  decomposition  of  their  na- 
"iiral  electricities.  The  repetition  then  of  such  discharges,  or  rather  their  continuation, 
must  occasion  in  the  apparatus  a  continued  electric  current,  the  energy  and  the  quan- 
tity of  which  depend  as  well  on  the  magnitude  and  the  nature  of  the  metallic  element^ 
in  contact  with  each  other,  as  on  the  greater  or  less  facility,  which  the  conducting  parts 
of  the  apparatus  present  to  the  transmission  of  electricity." — HIQT. 


78  APPENDIX. 

various  galvanic  processes,  have  been  lately,  very  closely  marked  and  reduced  even  ta 
precise  calculation.  From  among  these  we  may  adopt  the  following  general  law,  which 
has  been  clearly  established  by  M.  Biot,  namely ;  tiiat  «  each  of  the  two  electrical  princi- 
ples is  a  fluid,  -whose  particles,  perfectly  moveable,  mutually  repel  each  other,  and  attract  those 
of  the  other  principle,  -with  forces  reciprocal  as  the  square  of  the  distance.  JHso  at  equal  dis- 
tances the  attractive  power  is  equal  to  the  repulsive." 

This,  therefore,  being  an  established  law  which  characterizes  the  actions  of  these  fluids, 
is  it  not  reasonable  to  explain  the  material  phenomena  of  the  universe  by  its  assistance, 
especially  when  sucli  an  explanation  may  be  conducted  in  accordance  with  the  known 
laws  of  matter,  and  supported  by  the  conviction  that  the  atoms  of  every  material  sub- 
stance possess  certain  electrical  states  ? 

Another  very  important  law  which  regards  the  electric  fluids,  chiefly  with  respect  to 
the  atoms  of  matter  with  which  they  are  associated,  must  not  be  overlooked :  viz.  "  that 
a  mutual  attraction  exists  between  tixe  electric  fluid  and  all  material  substances,  when 
they  are  in  their  natural  state  of  electricity."  Hut  this  is  a  mere  extension  of  the  for- 
mer law  as  regards  the  connexion  of  these  fluids,  with  the  atoms  of  matter,  and  is  en- 
tirely the  result  of  the  electrical  influence  with  which  these  atoms  are  endowed,  as  we 
can  have  no  idea  of  matter  devoid  of  its  natural  electricity. 

Proceeding,  therefore,  upon  the  established  laws  of  electricity,  and  upon  these  which 
it  is  presumed,  the  particles  of  matter  obey,  it  may  be  concluded  that  the  cohesion 
which  exists  between  the  atoms  of  unorganized  substances,  results  from  the  attraction 
existing  between  the  opposite  electricities.  Whether  we  conceive  the  particles  of 
matter  to  exist  innately  endowed  with  certain  electrical  states,  or  surrounded  with  one 
or  other  of  these  fluids,  according  to  their  reciprocal  affinity,  still  the  attraction  be- 
tween the  atoms  of  matter  must  be  equally  the  result  of  opposite  states  of  this  univer- 
sally diffused  agent. 

But  it  may  be  contended,  that  as  the  particles  of  matter  mutually  repel  each  other, 
they,  therefore,  are  either  altogether  devoid  of  any  kind  of  electrical  influence,  or  are 
endowed  with  the  property  of  mutual  repulsion,  which  they  exert  notwithstanding  the 
electrical  agency.  But  this  objection  is  by  no  means  valid,  for  it  may  be  shown  that, 
even  granting  them  to  possess  the  property  of  mutual  repulsion,  the  supposition  is  fa- 
vourable to  the  theory,  and  serves,  moreover,  to  account  for  the  varied  phenomena  to 
which  the  different  particles  of  matter  and  the  electrical  fluids  give  rise. 

As,  however,  we  have  just  supposed  that  the  attraction  of  matter  results  from  the 
atoms  being  endowed  with  the  opposite  suite  of  electricity,  it  is  as  reasonable  to  sup- 
pose, that  an  opposite  condition  to  attraction  must  take  place  when  homogeneous  par- 
ticles, or  those  possessing  the  same  kind  of  electrical  energy,  are  brought  within  the 
sphere  of  action. 

From  this  consideration  we  are  led  to  the  conclusion  that  attraction  and  repulsion  be- 
tween the  particles  of  matter  arise  as  a  necessary  consequence  of  the  electrical  states 
of  these  particles.  The  various  anomalies  or  peculiar  conditions  of  material  substan- 
ces can  be  easily  supposed  to  result  from  certain  degrees  of  electrical  saturation,  or 
neutralization  to  which  these  substances  are  subjected. 

From  the  consideration  of  corpuscular  attraction  and  repulsion,  the  transition  to  che- 
mical affinity  becomes  evident. 

It  may  be  shown  by  direct  experiment,  that  repulsion,  can  be  produced  between  two 
bodies,  by  giving  one  of  them  an  electrical  state  different  from  that  which  it  naturally 
possesses;  t:--at  is,  by  bringing  it  artificially  into  a  condition  similar  to  the  other;  so 
chemical  attraction  between  two  bodies  may  be  increased  by  exalting  the  energy  of 
the  electrical  states  which  they  naturally  possess. 

As  chemical  affinities  are  the  result  of  attraction  or  repulsion  between  the  particles 
of  matter,  owing  to  their  electrical  conditions,  so  these  affinities  will  be  simple  or  com- 
pound, according  to  the  electric  states  of  the  different  materials  which  are  brought  into 
mutual  action,  and  according  to  the  various  energies  of  these  states. 

Having  endeavoured  to  establish  the  proposition  of  different  material  atoms  possess- 
ing different  electrical  states,  both  as  regards  its  negative  or  positive  modes  of  exist- 
ence, and  as  respects  the  energy  of  each,  and  having  considered  such  relations  suffici- 
ent to  account  for  the  phenomena  of  repulsion  and  gravitation,  it  becomes  unnecessary 
to  point  the  application  of  the  cicctrine  to  the  various  chemical  changes  which  take 
place.  However,  that  such  changes  actually  do  occur,  after  the  manner  which  a  priori 
reasoning  would  lead  us  to  expect,  is  a  general  inference  which  presents  but  very  few 
exceptions.  But  our  knowledge  respecting  the  abstract  state  of  these  substances 
which  present  the  presumed  exceptions  are>  as  yet  so  very  imperfect,  that  no  con- 
clusive argument  can  be  adduced  that  their  chemical  combination  is  not  the  result  of 


OF  GALVANIC  ELECTUICTV. 

the  electrical  states  of  their  atoms,  or  of  these  fluids  during"  their  continuous  circulation 
through  them. 

The  excitement  of  electricity  by  means  of  friction,  by  compression,  by  the  fusion  of 
inflammable  bodies,  by  evaporation,  by  the  disengagement  of  gas,  by  the  disruption  of 
a  solid  body,  by  the  contact  of  dissimilar  substances,  and  lastly  by  chemical  decomposi- 
tion— all  combine  in  establishing-  the  intimate  connexion  for  which  we  contend. 

Whenever  bodies,  brought  by  artificial  means  into  high  states  of  opposite  electricit;-, 
are  allowed  to  restore  the  electricity ;  heat  and  light  are  the  consequences.  [Davy.] 

These  effects  takes  place  in  the  same  manner  if  performed  in  a  vacuum.  The  light 
produced  in  this  manner  appears  from  the  experiments  which  have  been  related,  to  be  of 
the  same  nature  with  the  solar  beam,  and  to  be  divisible  into  the  prismatic  colours.  The 
light  exhibited  by  phosphorescent  bodies,  and  by  matter  under  its  various  conditions, 
gives  similar  results.  Therefore,  from  taking  a  survey  of  the  electrical  phenomena,  of 
those  displayed  by  chemical  combinations,  and  of  other  manifestations  of  nature,  v/e 
are  inclined'to  adopt  the  belief  that  light  and  caloric  (as  they  exist  in  the  solar  rays,  and 
as  they  are  otherwise  produced)  are  the  result  of  the  combination  and  neutralization  of 
the  opposite  electricities,  whether  taking  place  in  a  direct  manner,  and  in  their  free 
state  of  existence,  or  through  the  medium  of  the  particles  of  matter  which  they  endow; 
light  being  more  or  less  perfect  according  as  the  netralization  is  more  or  less  complete, 
and  the  caloric  resulting  from  the  intensity  of  their  action. 

Before  leaving  the  consideration  of  the  action  of  the  electric  fluids  upon  each  other, 
and  upon  the  molecules  of  matter,  it  is  necessary  to  remark  respecting  a  property  which 
the  molecules  of  matter  appear  to  possess  under  certain  circumstances,  of  arranging1 
themselves  in  definite  directions ; — this  has  generally  been  called  the  polarization  of 
matter — a  phenomenon  observed  in  the  crystallization  of  numerous  substances,  and  in 
different  chemical  actions.  The  polarization  of  the  atoms  of  matter  seems  to  result 
from  the  electrical  states  which  they  acquire  from  the  electricities  circulating  around 
them,  and  to  arise  from  a  property  with  which  the  electricities  are  themselves  endowed, 
or  from  their  mutual  action  independently  of  their  connexion  with  the  molecules  of 
matter.  According  to  this  view  of  the  subject,  we  should  be  led  to  expect,  that  the 
electricities,  as  they  exist  in  the  solar  beam,  unconnected  with  matter,  would  give  rise 
to  the  phenomenon  of  polarization,  in  a  similar  manner  as  when  their  action  is  ex- 


igencies and  the  mag- 
netical  attractions,  is  a  subject  which  has  lately  interested  scientific  inquirers  through- 
out Europe.  It  would  almost  seem,  from  their  observations,  that  manifestations  of  ths- 
magnetic  power  result  from  the  electrized  state  of  the  atoms  of  the  magnet,  and  their 
cpnsequent  polarization;  and,  from  the  continuous  circulation  of  the  electric  fluids 
either  through  its  substance  or  upon  its  surface*. 

Since  the  discoveiy  of  Galvarii,  several  physiologists  have  attempted  to  explain  the 
phenomena  of  the  animal  world,  by  imputing  the  functions  of  the  nervous  system  to 
the  electro-motive  energy,  generated  or  developed  by  the  cerebro-spinal  masses, 
Amongst  those  who  have  espoused  this  opinion  we  may  mention  Sprengel,  Reil,  Pro- 
chaska,  Wilson,  Philip,  Lenhossek,  &c.  There  can  be  no  doubt  that  the  electricities 
circulate  through  animal  bodies  in  different  conditions,  and  give  rise  to  subordinate  of' 
fices  in  the  animal  economy,  under  the  superior  dominion  of  a  vital  influence  ;  and 
moreover,  that  they  (or  one  of  them  at  least)  are  of  a  stimulus  to  to  this  influence. 
The  experiments  of  the  physiologists  just  named,  especially  those  of  Dr.  Philip  show 
this,  but  nothing  more  than  this.  They  refer  to  the  electrical  apparatus  which  certain 
fishes  possess,  and  the  power  they  have  of  giving  electrical  shocks  in  farther  proof  of 
the  justness  of  their  inference  ;  but  it  may  be  asked,  if  the  nervous  influence  be  the 
same  as  electricity,  why  should  these  animals  possess  an  apparatus  distinct  from  the 
nervous  system,  and  under  its  control,  for  the  production  otthe  electrical  phenomena  ? 
The  existence  of  this  apparatus  confirms  the  proposition  we  have  just  now  stated ; 


*  In  the  annual  oration  delivered  to  the  Medical  Society  of  London  in  1822,  we  en- 
deavoured to  show  that  the  phenomena  of  attraction  or  gravitation,  chemical  affinity, 
combustion,  chrystillization,  magnetism,  light  and  heat,  (both  as  they  exist  in  the  solar 
rays,  and  as  they  are  otherwise  produced,)  in  short,  that  all  the  phenomena  of  the  in- 
organized  world  and  of  the  solar  systems  may  be  explained  by  means  of  the  agency  of 
two  universally  diffused  electricities. 


$0  APPENDIX. 

snd  its  office  is  evidently  that  of  accumulating1  within  itself,  in  consequence  of  the 
vital  function  with  which  it  is  endowed,  the  electricities  circulating-  in  the  body,  so  that 
they  may  be  discharged  according-  to  the  wants  of  the  animal ;  but  the  electricities 
vhich.  the  anim.il  thus  accumulates  and  discharges  cannot  be  said,  from  the  evidence 
which  we  as  yet  possess  on  the  subject,  to  be  identical  with  its  nervous  influence,  noir 
•\yith  the  vitality  of  its  system  more  than  oxygen,  nitrogen,  hydrogen,  or  any  other 
fluid  constantly  present  in,  circulating  through,  and  con.i/ming  with  the  constituents 
of  the  body,  may  he  considered  to  be  the  source  of  its  numerous  manifestations.  The 
one  fluid  may  accumulate  in  the  system  as  well  as  the  other,  by  means  of  the  vital 
operations  of  the  organ  in  which  the  accumulation  takes  place,  and  it  may  be  again 
discharged  in  consequence  either  of  an  operation  determined  by  the  nervous  influence, 
or  of  some  other  process,  and  in  fact,  we  find  such  a  phenomenon  actually  taking  place  ; 
but,  are  we  to  infer,  on  that  account,  that  either  the  one  or  the  other  of  these  fluids 
constitute  the  vitality  of  the  system,  or  even  that  they  are  the  source  of  vitality,  when 
it  can  only  be  shown  to  be  a  single  function  from  amongst  the  many  which  the  animal 
exhibits  ?  We  find  that  electricity  is  accumulated  in,  and  discharged  from,  the  electri- 
cal apparatus  of  some  fishes  ;  and  we  also  perceive  that  oxygen  and  nitrogen  are,  in 
like  manner,  accumulated  in,  and  diacharged  from  the  swimming  bladders  of  other 
iishes  ;  but  these  circumstances  do  not  warrant  us  to  infer  that  electricity  is  the  nervous 
influence  of  the  former,  more  than  that  oxygen  is  the  nervous  influence  of  the  latter; 
or,  that  the  vitality  of  the  one  is  electricity,  of  the  other  it  is  oxygen. 

But,  although  the  agency  of  the  electricities  have  been  extended,  farther  as  respects 
the  animal  kingdom,  by  some  physiologists,  than  well  ascertained  facts  can  wan-ant, 
it  must  be  allowed,  from  the  evidence  which  has  been  adduced,  that  they  give  rise  to 
very  important  phenomena  when  they  are  brought  to  operate  on  some  of  the  animal 
textures.  It  is  these  effects,  or  rather  the  stimulus  which  electricity  imparts  to  the 
sensible  and  contractile  parts  of  the  body,  that  constitute  the  chief  physiological  rela- 
tions of  electricity,  and  give  a  degree  of  plausibility  to  the  doctrines  of  those  who  con- 
sider that  all  the  animal  functions  are  discharged  by  the  electricities  in  their  electro- 
motive condition.  These  circumstances  require  that  we  should  notice  at  farther 
length  the  effects  of  this  agent  on  the  animal  system*. 

"  According  to  Ritter,  the  electricity  of  the  positive  pole  augments  while  the  nega- 
tive diminishes  the  actions  of  life.  Tumefaction  of  parts  is  produced  by  the  former, 
depression  by  the  latter.  The  pulse  of  the  hand,  he  says,  held  a  few  minutes  in  con- 
tact with  the  positive  pole,  is  strengthened ;  that  of  the  one  in  contact  with  the  nega- 
tive is  enfeebled  ;  the  former  is  accompanied  with  a  sense  of  heat,  the  latter  with  a  feel- 
Ing  of  coldness.  Objects  appear  to  a  positively  electrified  eye,  larger,  brighter,  and 
red;  while  to  one  negatively  electrified  they  seem  smaller,  less  distinct,  and  bluish, — 
colours  indicating  opposite  extremes  of  the  prismatic  spectrum." 

An  electrical  practitioner  referred  to  by  Dr.  Ure,  from  whom  the  above  paragraph 
33  quoted,  considers  that  his  experience  in  the  application  of  this  agent  in  disease  war- 
rants him  in  referring  its  operation  to  three  distinct  heads  :  "  first,  the  form  of  radii, 
,-vvhen  projected  from  a  point  positively  electrified  ;  secondly,  that  of  a  star,  or  the  ne- 
gative fire  concentrated  on  a  brass  ball ;  thirdly,  the  Leyden'explosion." 

The  first  acts,  he  considers,  as  a  sedative  ;  the  second  as  a  stimulant ;  and  the  last 
has  a  deobstruent  operation.  Dr.  Ure  has  found  that  the  negative  pole  of  a  voltaic  bat- 
tery, gives  more  poignant  sensations  than  the  positive. 

•The  experiments  of  Dr.  Philip  with  voltaic  electricity  have  led  him  to  infer  that  the 
nervous  influence  is  nothing  else  than  this  agent.  This  proposition  has  already  been 


*  Amongst  the  living  tissues,  the  nervous  is  the  best  conductor  of  electricity ;  there- 
fore, when  an  electrical  current  is  established  through  the  body,  it  is  transmitted  by 
this  texture.  If  the  electrical  current  consists  only  of  one  of  the  electricities,  the 
molecules  composing  the  nervous  texture  tend  to  propel  each  other,  or  to  disunite  ; 
and  if  the  electrical  action  is  very  intense,  they  are  actually  decomposed,  and  con;f 
founded  with  the  fatty  matter  which  isolate  the  nervous  fibres ;  all  the  functions  of  the 
nerves  are  instantly  d'estroyed,  the  irritability  of  the  muscles  dissipated,  and  life  is  im- 
mediately terminated.  These  effects  are  frequently  witnessed  from  lightning.  They 
are  not  confined,  however,  to  the  nervous  and  muscular  systems,  all  the  soft  parts  are 
more  or  less  affected ;  the  blood  does  not  coagulate,  owing  to  the  dissipation  of  the 
rital  influence  giving  rise  to  the  phenomenon  of  coagulation  and  all  the  tissues 
quickly  into  a  state  of  putrefaction, 


OF  GALVANIC  ELECTRICITY.  81 

noticed,  and  it  will  be  again  referred  to ;  we  shall  only  observe  at  this  place,  that  his 
experiments  appear  to  show  the  extent  to  which  the  electro-motive  agency,  transmitted 
through  their  voluntary  nerves,  may  prove  a  stimulus  to  particular  organs,  and  enable 
them  to  perform  their  functions  when  these  functions  have  been  impeded  by  the  re- 
moval of  a  natural  and  requisite  stimulus.  We  have  at  another  place  endeavoured  to 
Show  that  the  functions  which  Dr.  Philip  has  imputed  to  the  cerebro-spinal  nerves  are 
actually  derived  from  another  source ;  that  the  operations  of  these  nerves  (with  the 
exception  of  the  nerves  of  sense)  are  chiefly  confined  to  the  transmission  of  the  cere- 
bro-spinal influence,  which  is  the  natural  stimulus  to  the  vital  endowment  that  the  or- 
gans receive  from  a  different  system — the  ganglial ;  but  that  this  stimulus  cannot  be 
considered  to  be  galvanism,  merely  because  galvanism  is  a  stimulus,  and  acts  in  a  man- 
ner which  we  have  every  reason  to  suppose  other  stimuli  would  act,  if  they  were  capa- 
ble of  being  transmitted  through,  and  be  present  in,  every  part  of  the  body,  on  which 
they  are  disposed  to  operate.  It  is  the  particular  constitution  of  this  agent,  its  pro- 
perties, and  its  relations  with  the  solids  and  fluids  of  the  body,  that  give  rise  to  its  ac- 
tive operation,  and  to  phenomena  liable  to  be  confounded  with  those  of  the  nervous 
system,  or  even  with  those  of  life  itself. 

What  we  have  just  new  adduced  has  a  stricter  reference  to  the  opinions  of  those 
who  consider  that  the  nervous  influence  and  galvanism  are  the  same,  we  shall  now  re- 
fer more  particularly  to  the  notion  of  the  identity  of  this  agent  and  life  itself ;  and 
here  we  cannot  do  better  than  quote  the  very  acute,  conclusive,  and  unanswerable  ob- 
servations of  Dr.  Pring*  (Principles  of  Pathoiogii^  on  this  subject.  *'  We  observe  that 
electricity  is  related  with  life,  and  acts  upon  it  T  this  is  no  proof  of  identity.  We  ob- 
serve also  that  electricity  will  substitute  in  some  instances  the  properties  derived  from 
a  nervous  centre  ;  in  this  respect  there  is  an  identical  property  common  to  it  and  life, 
which  is  also  possessed  by  many  other  substances.  We  observe,  also  that  the  forma- 
tion of  heat,  and  the  faculty  of  generating  electricity,  belong1  to  animals,  and  are  de- 
pendent upon  their  life.  The  faculty  of  generating  electricity,  in  animals,  does  not 
prove  that  electricity  is  even  a  constituent  part  of  their  life  :  it  proves  that  it  is  a  phe- 
nomenon of  their  life  ;  but  that  it  is  a  part  of  it,  is  no  more  to  be  concluded  on  this 
account,  than  that  urine,  or  mucusj  &,c.  is  a  part  of  life,  because  these  are  also  products 
of  it. 

"  We  have  made  out  then  only  one  point  of  resemblance  between  life  and  electri- 
city, which  is,  that  electricity  will  in  some  cases  substitute  a  property  otherwise  de- 
rived from  a  nervous  centre  ;  which  property,  applied  to  the  stomach,  will  aid  diges- 
tion, in  which  respect,  it  has  not  yet  been  "found  that  more  common  stimuli  resemble 
it :  applied  to  the  voluntary  muscles,  it  will  produce  their  contraction,  and  in  this  re- 
spect the  property  is  a  common  one  to  many  other  substances,  which  no  one  ever 
thought  of  identifying  with  life.  But  even  the  properties  which  are  said  to  depend 
upon  a  nervous  centre,  are  not  all  of  them  substituted  by  electricity,  which  will  stimu- 
late muscular  contraction,  like  many  other  substances,  but  like  those  substances  also, 
it  is  incapable  of  conferring  sensibility ;  or  if  electrical  influence  ever  excites  sensation 
in  paralytic  limbs,  it  is  only  because  their  sensibility  is  not  totally  extinct,  and  will 
therefore  admit  of  sensation  under  the  application  of  this,  or  of  any  other  stimulus,  of 
a  powerful  kind. 

"  We  have  seen  that  electricity  can  do  a  very  little  which  is  also  done  by  life ;  there 
is  then  analogy  in  one  property,  but  to  be  the  same  identity,  there  must  be  analogy  in 
all ;  or  to  approach  to  such  identity  there  must  be  at  least  a  general  analogy.  The  liv- 
ing principle  maintains  itself  by  assimilation  from  exposure  to  its  elements ;  electricity 
is  not  capable  of  maintaining  itself  from  its  elements,  but  must  be  produced  from  them. 
Muscular  power  in  the  animal  system  is  related  with  mind,  and  directed  by  volition ; 
we  have  no  evidence  that  mind,  or  volition,  independently  of  the  properties  which  dis- 
tinguish t'ue  living  state,  can  so  ally  itself  with  electricity.'  Animal  life  confers  sensibi- 
lity on  structures  ;  electricity  can  merely  excite  sensation  in  common  v  ith  chemical  and 
mechanical  stimuli.  The  organic  life  produces  from  a  common  material,  arranges  and 
renovates,  in  the  muscular  system,  the  particles  which  compose  muscle ;  in  the  tendons, 
those  of  tendon  ;  in  the  membranes,  those  of  membrane  :  in  the  bones,  the  constituents 
of  these  structures  ;  and  of  all  otlu  "s,  with  all  their  circumstances,  however  diversified, 
Now  if  electricity  were  capable  of  doing  all  this,  there  would  then  be  established  only  a 
general  resemblance  with  life ;  analogies  would  afterwards  be  sought  for,  corresponding 

*  We  recommend  the  physiologist  to  study  closely  the  physiological  and  pathologi- 
cal writings  of  this  most  acute  and  philosophical  writer. 

Li 


82  APPENDIX. 

with  these  powers  exhibited  by  the  relation  of  properties  of  life  in  different  seats,  and 
more  especially  among  the  phenomena  of  disease.  But  until  the  pretensions  of  elec- 
tricity to  an  identity  with  life  shall  be  established  by  rather  a  more  extensive  analogy, 
it  is  superfluous  to  inquire  how  far  the  phenomena  of  electricity  resemble  those  of  dys- 
pepsia, diarrhoea,  consumption,  abscess,  or  gout.  If,  perchance,  electricity  should  be 
endowed  with  the  properties  engaged  in  these  phenomena,  it  will  be  greatly  indebted 
to  its  friends,  for  bestowing  upon  it  attributes  which  it  has  never  displayed.  In  the 
mean  time,  it  is  to  be  wished  that  experimentalists  will  go  on  multiplying  their  facts, 
and  that  they  will  abstain  from  reasoning  upon,  them  :  they  will  not,  however,  err  to 
to  any  great  extent  in  this  way,  if  they  will  take  the  trouble  to  remember  that  so  far  as 
things  are  proved  to  be  alike,  they  are  alike  ;  and  where  they  are  not  proved  to  be 
alike,  it  is  possible  that  they  may  be  different. 

"The  identity  of  life  and  electricity,  or  galvanism,  has  been  inferred,  as  appears 
from  the  preceding  account,  from  very  slender  premises:  but  the  arguments  just  con- 
sidered are  among  the  best  that  have  been,  proposed  in  favour  of  the  sameness  of  the 
two  principles,  or  substances,  if  they  are  substances," 


Of  Ossification, 
Note  HIT. 

The  bones  are  at  first  of  a  mucous  or  gelatinous  consistence  in  the  embryo.  TtV; 
r.ext  become  cartilaginous,  and  some  of  them  fibro-cartilaginous ;  they  are  lastly  per- 
fectly ossified.  At  the  early  period  of  the  embryal  state  the  bones  gradually  increase,, 
without  any  apparent  division,  into  separate  parts.  The  cartilaginous  bones,  or  the 
temporary  cartilages,  do  xot  appear  before  two  months  have  elapsed  from  the  period 
of  conception,  and  then  this  process  towards  ossification  only  commences  in  those 
bones,  or  in  the  parts  of  bones  which  are  ossified  at  a  later  period.  It  appears  doubt- 
ful whether  or  no  those  bones  which  ossify  the  first,  or  those  parts  of  bones  in  which 
the  process  takes  place  at  an  early  period,  pass  through  an  intermediate  or  cartilagi- 
nious  state.  It  seems  most  probable  from  the  observations  of  Messrs.  Beclard  and  Ser- 
res,  that  in  them  the  ossific  deposit  is  made  in  the  first  or  mucous  state  of  their  exist- 
ence ;  whilst,  in  those  bones  which  are  perfected  at  a  remoter  period,  the  cartilaginious 
or  intermediate  state  which  they  assume  is  rather  a  provisional  function,  than  a  stage  ot 
ossification— a  temporary  condition  of  structure  forthe  purpose  of  performing  the  offices 
of  bone,  and  not  a  requisite  antecedent  to  the  ossific  process. 

Ossification  commences  successively  in  the  different  bones,  from  about  a  month  after 
impregnation,  in  those  which  are  the  first  formed,  until  ten  or  twelve  years  after  birth, 
in  those  which  ossify  at  a  later  period  ;  and  in  certain  subordinate  parts  of  bones,  the 
ossific  process  does  not  commence  until  the  fifteenth  or  eighteenth  year.  The  clavicle 
MK!  maxillary  bones  are  amongst  the  first  developed  ;  the  sternum,  the  bones  of  the 
pelvis,  and  those  of  the  extremities  are  the  latest.  It  may  be  considered  as  a  general 
proposition  that  those  bones  which  are  nearest  the  nervous  and  sanguineous  centres 
are  the  first  to  be  formed,  as  if  their  more  immediate  developement  were  required  to 
protect  these  important  systems  ;  hence  we  perceive  that  the  vertebrae  and  ribs  ossify 
at  an  early  period. 

At  the  end  of  the  first  month  ossification  commences  in  the  clavicle,  and  successively 
in  the  inferior  maxilla,  in  the  femur,  tibia,  humerus,  superior  maxilla,  and  bones  of  the 
fore-arm,  where  it  begins  about  the  thirty-fifth  day.  About  the  fortieth  day  this  pro- 
cess commences  In  the  fibula,  scapulum,  the  palatine  bones ;  and  during  the  following- 
('.ays,  in  the  occipital  and  frontal  bones,  in  the  arches  of  the  first  vertebra:,  and  in  their 
sides,  in  the  sphenoid,  the  zygomatic  apophysis,  the  phalanges  of  the  fingers,  the  bodies 
of  the  vertebrae,  the  nasal  and  zygomatic  bones,  the  ilium,  the  metacarpal  bones,  the 
condyles  of  the  occipital  bones,  in  the  squamous  portion  of  the  temporal  bone,  the  pa- 
rietal, and  in  the  vomer  ;  in  all  these  ossification  begins  about  the  middle  of  the  seventh 
week.  In  the  course  of  the  same  week  it  commences  also  in  the  orbitar  process  of  the 
sphenoid  ;  and,  about  the  end  of  the  week,  in  the  metatarsal  bones  and  phalanges  of 
the  fingers  and  toes.  During  the  ten  following  days  it  begins  in  the  first  sacral  verte- 
bra:, and  around  the  tympanum.  During  the  subsequent  weeks  and  months  it  com- 
mences in  the  bones  or  the  ear,  in  the  pubis,  in  the  processes  of  many  of  the  already 
mentioned  bcnes,  in  the  small  bones  of  the  extremities,  8cc.  (Beclard.) 


OF  VOICE.  83 

Ossification  docs  not  result,  as  we  have  already  noticed,  from  the  transformation  of 
cartilage  into  bone.  The  diaphysis  of  the  long" bones,  and  the  centre  of  the  large 
bones,  which  are  amongst  those  first  formed,  pass  immediately  from  a  mucous  to  an  os- 
seous state.  The  other  parts  of  this  structure  have  an  intermediate  cartilaginous  con- 
dition ;  and  it  is  in  these  parts  that  the  successive  stages  of  ossification  may  be  best  ob- 
served. 

The  cartilage  which,  for  a  longer  or  shorter  period,  supplies  the  place  of  bone,  be- 
comes at  first  hollowed  into  irregular  cavities,  afterwards  into  canals  lined  with  a  vascu- 
lar membrane  and  filled  by  a  mucilaginous  and  viscid  liquid  ;  these  canals  become  red, 
the  cartilage  now  assumes  an  opaque  appearance,  and  ossification  commences  towards 
its  centre.  The  first  point  of  ossification  is  always  in  the  centre  of  the  cartilage,  and 
never  at  its  surface.  This  point  is  surrounded  by  a  reddish  cartilage,  and  that  part 
which  is  nearest  it  is  opaque  and  pierced  with  canals  still  farther  than  opacity  reaches. 

The  osseous  point  augments  progressively  by  means  of  additions  on  its  surface,  as 
well  as  by  an  interstitial  deposit  in  its  substance.  The  cartilage  gradually  becomes 
hollowed  by  cavities  and  canals,  lined  by  a  vascular  sheath,  diminishes  as  the  ossifica- 
tion extends,  and  disappears  altogether  when  the  process  is  completed. 

With  respect  to  the  state  in  which  the  osseous  matter  is  formed,  we  are  inclined  to 
agree  with  Mr.  Beclard,  in  the  opinion  that  the  earthy  matter  is  deposited,  in  a  fluid 
condition,  and  at  the  same  time  with  animal  matter,  jn  the  organized  tissue  which  se- 
cretes it.  Its  subsequent  solidification  arises  either  from  the  deposition  of  a  larger  pro- 
portion of  earthy  matter,  or  from  the  absorption  of  the  vehicle  which  gives  it  the  fluid 
condition ;  or  from  the  joint  operation  of  both  these  causes. 


Of  Voice. 
Note  HH*. 


The  cricoid  cartilage,  which  supports  the  two  arytenoid  cartilages,  is  not  immovea- 
ble  at  the  inferior  part  of  the  larynx.  The  trachea  to  which  it  is  attached  by  its  inferior 
margin,  yields  and  elongates  itself  in  order  to  allow  it  motion.  The  muscles  of  the 
Sarynx  do  not  contribute  to  the  production  of  the  voice  solely  by  means  of  the  action 
which  they  exercise  on  the  sides  of  the  glottis  ;  several  of  them,  and  particularly  the 
thyro-arytenoids,  may  be  considered  as  forming  part  of  the  parietes  of  this  opening. 
These  small  muscles  give  rise  to  acute  sounds  by  drawing  closer  the  two  arytenoid  car- 
tilages, and  when  in  a  state  of  contraction  they  also  seem  susceptible  of  a  vibratory  uio- 
tion,  varying  iu  degree  according  to  the  degree  of  contraction  :  by  the  assistance,  there- 
fore, of  the  muscular  fibres  covering  its  sides,  the  glottis  is  susceptible  of  vibrations 
snalagous  to  that  of  the  lips  applied  to  the  opening  of  a  French-horn.  The  production 
of  sound  is  owing  to  the  action  of  the  muscles  of  the  larynx  on  its  cartilages,  during  ex- 
piration ;  and  whatever  impeds  the  functions  of  the  nerves  actuating  these  muscles, 
puts  a  stop  to  the  utterance  of  sound. 


Of  Ventriloquism. — Various  attempts  have  been  made  to  explain  the  manner  in  which 
the  ventriloquist  is  enabled  to  modify  his  articulations  into  the  semblance  of  distinct 
voices.  Dr.  Good  considers  ventriloquism  "  to  be  an  imitative  art,  founded  in  a  close 
attention  to  the  almost  infinite  variety  of  tones,  articulations,  and  inflexions,  which  the 
glottis  is  capable  of  producing  in  its  own  region  alone,  when  long  and  dexterously 
practised  upon  ;  and  a  skilful  modification  of  these  vocal  sounds,  thus  limited  to  the 
glottis,  into  mimic  speech,  passed  for  the  most  part,  and  whenever  necessary,  through 
the  cavity  of  the  nostrils,  instead  of  through  the  mouth."  He  farther  supposes  that 
"  some  peculiarity  in  the  structure  of  the  glottis,  and  particularly  in  respect  to  its  mus- 
cles and  cartilages,"  is  requisite  to  carry  this  art  to  perfection.  The  explanation  -/rhich 
Magendie  otters  on  this  subject,  appears  to  us  to  be  more  correct,  although  perhaps  not 
sufficiently  so.  This  physiologist  asserts,  that  ventriloquism  consists  in  certain  modifi- 
cations of  sounds  or  speech,  produced  by  a  larynx  of  the  common  formation,  with  a 
strict  attention  to  the  different  effects  of  sound  thrown  at  different  distances,  and 
through  different  modes  of  conveyance.  We  cannot  agree  with  Dr.  Good  that  the 
ventriloquist  performs  articulation  by  means  of  the  larynx  only,  although  we  may  con- 


84  APPENDIX. 

cede  some  share  in  the  process  to  this  organ  j  nor  can  it  be  granted  that  any  "  addition 
to  the  muscular  organism  of  the  glottis"  is  enjoyed  by  those  who  have  perfectly  ac- 
quired this  imitative  art. 


Of  the  Generative  Organs  and  their  Functions. 
Note  I.I. 

I.  Of  the  Male  Organs  of  Generation — -The  cellular  structure  of  the  corpora  caver- 
nosa  penis,  according  to  the  microscopic  examinations  of  Mr.  Bauer,  appears  to  be  made 
up  of  an  infinite  number  of  thin  membraneous  plates,  exceedingly  elastic,  so  connected 
together  as  to  form  a  trellis  work,  the  edge  of  which  is  firmly  attached  to  the  strong1 
elastic  ligamentoiis  substance  which  surrounds  the  whole,  and  also  forms  the  septum  pec* 
tint-forme.    This  substance  has  an  admixture  of  muscular  fibres    The  cells  are  generally 
larger,  or  rather  the  trellis  work  is  more  loose  in  the  middle  portion  of  each  corpus  ca,- 
vernosum.  - 

Arterial  ramifications  are  supported  by  this  reticular  structure,  and  they  are  distribut- 
ed every  where  througout  the  cavernous  part  of  this  organ.  In  the  usual  state  of  the 
penis,  the  blood  is  not  poured  into  the  cells,  but  returns  by  the  veins,  and  it  remains 
flaccid;  but  when  a  person  is  under  the  influence  of  particular  impressions,  the  minute  ar- 
terial branches  which  before  had  their  orifices  closed,  now  have  their  actions  suddenly 
increased,  and  pour  from  their  open  mouths  the  blood  into  these  cells  so  as  to  overcome 
the  elastic  power  that  under  ordinary  circumstances  keeps  them  collapsed. 

The  corpus  spongiosum  penis  appears,  from  the  observations  of  the  same  physiolo- 
gist, to  consist  of  the  same  kind  of  structure  as  that  observed  in  the  corpora  cavernosa, 
but  on  a  less  scale.  Its  structure  iso  als  more  regular  throughout ;  without,  however, 
having  any  muscular  fibres  mixed  with  the  trellis  work,  these  being  confined  to  the 
outer  surface  of  the  inner  membrane  of  the  urethra.  The  erection  of  this  part  is  sup- 
posed to^take  place  after  the  same  manner  as  that  of  the  corpora  cavernosa,  namely, 
from  a  vital  expansion  taking  place  in  the  extremeties  of  the  arterial  capillaries,  and 
thus  allowing  the  blood  to  flow  from  them  into  the  cells  of  both  structures. 

We  may  state,  moreover,  that  the  arteries  of  the  penis  are  surrounded  by  a  larger  pro- 
portion of  nerves  than  in  most  of  the  other  tissues  of  the  body.  The  veins  form  very 
numerous  anastomoses.  It  is  the  division,  on  dissection,  of  these  numerous  veins,  and  of 
their  numerous  roots,  anastomoses,  and  plexuses,  which  in  the  opinion  of  M.  Beclard, 
gives  the  appearance  of  cells,  the  existince  of  which  he  denies.  Erection  of  this  tex- 
ture is  the  result  of  the  influence  of  the  nerves  upon  the  arteries  and  veins  belonging  to 
it.  By  this  influence  the  action  of  the  arteries  is  increased,  whilst  the  diamter  of  the 
veins  returning,  the  blood  is  diminished  by  the  tonic  contractility  which  these  nerves 
exert  on  the  coats  of  the  veins. 

Messrs.  Prevost  and  Dumas  have  both  examined  the  spermatic  animalcule.  They 
seem  to  vary  in  form  in  different  animals,  and  to  be  the  product  of  a  real  secretion, 
These  physiologists  conclude,  "  1st,  that  spermatic  animalculae  have  nothing  in  com- 
mon with  infusory  ones,  except  in  their  microscopic  size ;  2d,  that  they  are  produced  in 
the  testes  alone,  but  do  not  appear  in  these  organs  till  the  age  of  puberty ;  and  3d,  that 
they  seem  to  be  the  active  principle  or  agent  of  the  semen." 

The  vesiculx  seminales  may,  under  particular  circumstances,  more  likely  to  occur  in 
the  human  species  than  in  'the  lower  animals,  be  employed  as  reservoirs ;  although 
their  ordinary  use  may  be  to  secrete  a  fluid  which,  mixing  with  the  semen  in  coitu,  may 
render  the  act  more  perfect,  and  more  likely,  therefore,  to  produce  fecundation. 

II.  Of  the  Female  Organs  of  Generation, — The  uterus,  the  ovaria,   and  the  fallopian 
tubes  receive  their  nerves  from  the  abdominal  portion  of  the  trisplanchnic  nerves,  bran- 
ches of  which  unite  variously  with  each  other,  and  form  six  plexuses.     The  first,  which 
M.  Tiedemann  calls  spermatic,  or  the  ptexus  common  to  the  ovaria  and  tubes,  is  situat- 
ed on  the  anterior  surface  of  the  abdominal  aorta,and  on  the  origin  of  the  internal  sper- 
matic artery.  It  is  formed  of  a  number  of  branches,  which  come  from  the  renal  ganglia. 
Its  iilaments  descend,  surrounding  the  arteries  of  the  ovaria,  between  the  membranes 
which  form  the  broad  ligaments  of  the  uterus,  and  arrive  at  the  ovaria  and  tubes,  in 
•which  they  are  ramified  :  a  few  filaments  reaches  the  fundus  of  the  uterus. 

The  second  plexus,  which  is  the  largest,  Mr.  Tiedemann  calls  the  superior  lumbar  plex- 


OF  THE  GENERATIVE  ORGANS,  ETC.  85 

y.v,  or  common  uterine.  It  is  formed  of  branches,  which  proceed  from  the  superior  lum- 
bar and  renal  ganglions  ;  and  is  placed  on  the  body  of  the  fifth  lumbar  vertebra,  and  011 
the  promontory  of  the  sacrum,  between  the  iliac  arteries.  On  its  entrance  into  the  pel- 
vic basin,  it  divides  itself  into  two  considerable  plexuses,  which  M.  T.  calls  the  hypo- 
gastric  or  lateral  uterine  plexuses.  These  are  placed  on  the  trunks  of  the  iliuc  arteries, 
and  anastomose  with  the  first  and  second  sacral  ganglions.  A  great  many  filaments  pro- 
ceed from  these  plexuses,  forming  a  reticulum  around  the  arteries  of  the  uterus,  with 
the  ramifications  of  which  they  penetrate  into  the  texture  of  the  organ,  ckiefly  its  pos- 
terior and  lateral  aspects. 

Several  branches  proceed  from  the  superior  lateral  or  hypogastric  plexus  to  the  vagina, 
at  the  point  of  its  union  with  the  neck  of  the  uterus,  and  there  unite  with  the  anterior 
branches  of  the  third  and  fourth  sacral  nerves,  and  form  a  large  plexus,  which  M.  Tie- 
demann  calls  the  inferior  lateral  hijpogastric,  and  which  interweaves  with  and  embraces 
small  ganglia.  The  gangliform  plexus  gives  origin  to  a  great  many  branches,  chiefly  to 
the  vagina,  to  the  uterus,  and  also  to  the  bladder  and  rectum.  These  nerves,  as  well 
as  those  belonging  to  the  other  plexuses,  always  closely  embrace  the  arteries  in  the 
form  of  a  net  work. 

It  appears,  therefore,  that  the  womb  and  its  appendages  are  surrounded  by  important 
nervous  plexuses.  These  nerves  are  soft,  small,  reddish-gray,  and  in  every  respect  si- 
milar to  the  other  portions  of  the  great  sympathetic  nerves.  Of  their  appearance  and 
character  we  have  had  several  opportunities  of  satisfying  ourselves,  when  making  re- 
searches respecting  this  grand  organic  system,  and  we  can  bear  testimony  to  the  cor- 
rectness of  the  observations  of  M.  Tiedemann. 

M.  Tiedemann  states  that  the  number  and  size  of  the  uterine  nerves  vary  according 
to  the  age  of  the  female  ;  that  they  are  small  and  apparently  few  in  girls — large  and 
numerous  in  adults — and  very  small  in  old  women.  He  has  observed  another  fact,  con* 
firmatory  of  their  functions  which  indeed  was  previously  noticed  by  Dr.  W.  Hunter  and 
Professor  Chaussier,  that  these  nerves  become  larger  and  more  numerous  during  ges- 
tation. 


III.  Of  Impregnation. — Several  opinions  have  been  entertanined  respecting  the  im- 
pregnating process.  Some  physiologists  suppose  that  the  actual  contact  of  the  ovum 
and  semen  are  requisite ;  others  that  the  aura  seminalis  is  all  that  is  requisite.  Of  the 
former  cfass  of  physiologists  some  suppose  that  the  semen  is  absorbed  into  the  uterus, 
where  the  ovum,  having  descended  through  the  fallopian  tubes,  meets  it ;  others  con- 
sider that  the  semen  is  conveyed  by  a  paristaltic-like  action  of  the  vagina,  uterus,  and 
tubes,  to  the  ovarum  ;  and  the}'  adduce,  in  support  of  their  opinion,  the  occurrence  of 
extra  uterine  fcctation ;  a  third  party,  belonging  to  this  class,  conceives  that  the  semen 
is  conveyed  to  the  ovum  itself,  in  its  situation  in  the  ovarium,  by  means  of  absorption 
through  a  set  of  vessels  allotted  to  this  specific  purpose.  Dr.  Dewees,  of  Philadelphia, 
has  argued  strenuously  for  this  last  doctrine  :  it  has  also  been  adopted  by  other  physio- 
logists, and  it  seems  to  have  received  support  from  the  labours  of  Dr.  Gartner,  of  Co- 
penhagen, who  has  discovered  in  some  animals  a  duct  leading  from  the  ovary  to  the  va- 
gina. The  occurrence  of  ovarian  foctation,  wherein  the  foetus  is  lodged  within  the  en- 
veloping membrane  of  the  ovarium,  can  be  most  satisfactorily  explained  by  means  of 
this  doctrine.  Two  cases  of  this  description  have  lately  been  detailed  by  Dr.  Gran- 
ville  and  Mr.  Painter.  It  must,  however,  be  allowed  that  the  latter  class  of  physiolo- 
gists, or  those  who  contend  for  the  impregnation  influence  of  the  aura  seminalis,  have 
it  in  their  power  to  adduce  strong  arguments  in  behalf  of  their  opinion.  It  has  even 
been  asserted  very  recently,  by  some  continental  physiologists,  that  the  impregnating 
power  of  the  aura  seminalis  may  be  proved  by  experiment  performed  on  rabbits,  in  the 
following  manner  :  Let  the  semen  be  received  in  a  cup,  over  which  is  to  be  immedi- 
ately placed  an  inverted  funnel ;  and  let  the  apex  of  this  funnel  be  introduced  into  the 
vagina.  If  this  experiment  be  performed  immediately  after  the  seminal  emission,  they 
say  that  impregnation  will  be  the  result. 

It  has  been  argued  that  the  venereal  desire  is  present  in  neither  sex  before  the  de- 
velopment of  the  testes  and  ovaria.  This,  however,  is  not  the  case.  The  venereal 
appetite  makes  its  appearance  in  both  girls  and  boys  long  before  the  generative  organs 
are  developed.  It  has  been  frequently  observed  in  them  both,  in  temperate  cb'mates, 
as  early  as  the  sixth  or  seventh  year.  It  has  also  been  supposed  that  the  venereal  ap- 
petite disappears  soon  after  the  menses  have  ceased  to  flow  :  this  also  is  not  the  case. 
With  respect  to  the  assertion  that  the  venereal  orgasm  on  the  part  of  the  female  is 
necessary  to  impregnation,  we  may  observe  that  although  it  may  be  requisite  in 


8G  APPENDIX. 

some  females,  it  is  by  no  means  so  in  others ;  for  many  women  conceive,  who  are  indif- 
ferent during- the  venereal  congress;  there  are  others  who  conceive,  notwithstanding  their 
successful  endeavours  to  suppress  their  orgasm ;  and  some  are  impregnated,  when  owing 
to  disease,  as  procidentia  uteri,  &c.  they  cannot  be  supposed  to  enjoy  much  pleasure 
from  the  act.* 

Dr.  Blundell  found  in  his  experiments  that  when  only  one  of  the  uteri  of  a  rabbit  was 
divided*  or  rendered  impervious  at  its  neck,  or  when  the  passage  to  both  was  obstruct- 
ed by  tying  the  vagina,  and  iifterwards  freely  admitted  to  the  male,  that  the  obstruct- 
ed uterus,  or  uteri,  did  not  become  impregnated  ;  but  he  found,  in  those  whose  vagina 
was  tied,  that,  notwithstanding,  the  ovaries,  fallopian  tubes,  and  womb  were  excited  by 
coition;  and  in  those  who  admitted  the  male  frequently,  the  abdomen  acquired  a  large 
size,  and  in  some  cases  exceeded  the  bulk  of  mature  gestation.  These  enlargements 
arose  from  an  accumulation  of  a  humour  in  the  womb,  which,  at  a  temperature  below 
boiling,  formed  albuminous  concretions.  In  its  appearance  it  was  various,  but  general- 
ly fluid,  pale  and  turbid.  In  those  who  had  only  one  uterus  obstructed,  the  sound  one 
became  filled  with  foetuses,  and  the  barren  one  with  the  humour  described.  The  for- 
mation of  the  lutea,  the  development  of  the  womb,  and  the  repeated  accumulations  of 
fluid  in  consequence  of  coition,  in  these  experiments  seem  to  indicate  the  descent  of 
the  rudimental  material. 

Thus  although  the  passage  to  the  uterus  was  completely  interrupted,  the  tubes  were 
excited  by  the  venereal  org'asm,  they  really  conveyed  the'rudiments  to  the  womb,  and 
these  rudiments  engendered  the  watery  accumulations  there  in  the  abortive  attempts 
at  generation.  This  appears  to  confirm  the  supposition,  and  indeed  to  establish  it,  that 
even  in  viviparous  animals,  generation  may  be  carried  to  a  certain  extent,  although  the 
access  of  the  semen  to  the  rudiments  is  interrupted ;  under  these  circumstances  the 
young  animal  cannot  be  formed,  it  is  true,  but  corpora  lutea  may  be  generated,  the 
womb  may  be  developed;  and  the  rudiments  may  be  transferred  to  the  uterine 
cavity  by  the  play  of  the  fallopian  tubes.  This  opinion  receives  countenance  from  the 
generation  of  oviparous  animals,  in  most  of  whom  the  rudiments  may  be  discharged 
independently  of  preeceeding  impregnation. — (J\Ied.  Chirug.  Trans.  Vol.  10. ) 

Dr.  Blunde'll  supposes  that  the  vagina  and  womb  perform  a  peristatic  motion  from 
the  stimulus  of  the  semen,  both  in  the  haman  subject  and  lower  animals  ;  and  that  this 
motion  conveys  the  semen  to  the  rudiments. 

i'rom  these  experiments  it  would  appear  that  the  presence  of  corpora  lutea  can- 
not be  relied  upon  as  a  proof  that  impregnation  had  taken  place.  There  is  .even  evi- 
dence that  they  may  be  produced  even  independently  of  the  sexual  intercourse,  from 
the  mere  excitement  of  desire  in  a  high  degree.  Dr.  Blundell  has  in  his  possession  a 
preparation  of  the  ovaria  of  a  young  woman  who  died  of  chorea  under  seventeen  years 
of  age,  in  which  the  hymen  was  unbroken,  and  nearly  closed  the  entrance  of  the  va- 
gina. In  these  ovaries  the  corpora  lutea  are  no  fewer  than  four — two  rather  obscure, 
the  other  two  perfectly  distinct. 

As  Dr.  BlundelPs  experiments  goto  prove  that  impregnation  cannot  take  place  with- 
out the  semen  coming  in  contact  with  the  rudiments,  he  therefore  supposes,  that  when 
the  ovary  lodges  either  in  the  tubes,  the  peritoneal  cavity,  or  in  the  ovary  itself,  anil 
there  impregnated,  that  the  semen  must  be  conveyed  to  those  situations.  Or,  that  the 


*  Sir  Everard  Home  (PMksoph.  Tram.  1818)  states  that  corpora  lutea  are  never  met 
with  before  puberty.  They  are  formed  is  the  loose  structure  of  the  ovarium  previous  to 
and  independent  of,  sexual  intercourse ;  and  when  they  have  fulfilled  their  office  of 
forming  ova,  they  are  afterwards  removed  by  absorption,  whether  the  ova  be  impregnat- 
ed or  not.  It  seems  that  the  ovum  too,  with  its  amnion  and  chorion,  is  formed  in  the 
virgin  after  puberty.  This  was  found  to  be  the  case  in  a  woman  of  20  years  of  age, 
who  had  a  perfect  hymen.  "The  fallopian  tube  of  that  side  was  fuller  than  the  oppo- 
site. The  fimbriae  were  spread  out,  and  unusually  vascular."  We  know  that  animals 
part  with  their  eggs  whether  there  be  sexual  intercourse  or  not ;  and  this  is  done  with 
such  force  during  coition  that  the  cavity  of  the  corpus  luteum  is  absolutely  inverted,  so 
that  the  ovum  is  exposed  completely  to  the  emission  of  the  male.  Extravasation  of 
blood  follows  the  rupture  of  the  ovum  frequently  to  so  great  a  degree  that  blood  occa- 
sionally passes  out  through  the  vagina.  In  nine  months  after  impregnation,  the  cor- 
pus luteum  is  nearly  absorbed,  but  a  new  one  is  usually  found  in  a  state  of  forwardness 
in  the  other  ovarium.  All  preparations  of  corpora  lutea,  which  are  made  from  women 
who  have  died  in  child-bed,  belong,  in  Sir  E.'s  opinion,  to  ova  which  were  to  suo 
not  to  the  ovum  of  the  child  which  had  been  born. 


OF  THE  DEVELOPMENT  OF  THE  FOETUS,     (     37 

rudiment  in  its  descent  meet  the  semen  in  its  ascent,  and  that  the  transfer  of  the  semen 
beyond  the  womb  may  be  the  cause  of  extra  uterine  pregnancy. 


IV.  Of  Superfatati'm. — M.  de  Bouillon  (Kullet.  de  la  FaaiL  et  dfi  la  Soci&e  de 
cine,  JVb.  3.)  has  adduced  an  instance  of  superfoetation  in  a  Negress.  At  the  end  of  her 
pregnancy  she  was  delivered  of  two  male  children,  full-grown,  and  of  the  same  propor- 
tions, but  the  one  a  Negro  and  the  other  a  Mulatto.  The  mother,  after  a  long  resistance, 
confessed  that  she  had  connexion  the  same  evening  with  a  white  and  a  negro.  Similar 
instances  have  lately  been  detailed  in  the  American  journals,  of  which  we  shall  only  in- 
stance the  following  : — A  white  woman,  near  Philadelphia,  is  said  by  Dr.  Dewees,  to 
to  have  been  delivered  of  twins,  one  of  whom  was  perfectly  white,  the  other  black. 
The  latter  of  these  had  all  the  characteristics  of  the  African,  whilst  the  former  was  de- 
licate, fair-skinned,  light-haired,  and  blue-eyed.  Similar  cases  have  been  detailed  by 
Dr.  Elliotson,  and  Drs.  Norton  and  Stearns,"  of  New-York. 

Superfcetation,  in  our  opinion,  can  only  take  place  under  circumstances  similar  to 
those  which  produced  it  in  the  foregoing  instances  : — in  them,  it  would  seem,  that  there 
had  been  connexion  with  different  individuals  within  a  short  space  of  time.  We  con- 
ceive that,  when  the  decidua  is  thrown  out  and  the  ovium  has  formed  its  connexions, 
superfostation  is  then  impossible,  unless  in  the  case  of  a  double  uterus. 


Of  the  Development  of  the  Textures  and  Organs  of  the  Foetus. 
Note  KK*  -^ 

It  was  our  intention  to  have  illustrated  this  subject  at  considerable  length ;  but  we 
have  so  far  exceeded  our  limits  that  we  must  no^  be  brief. 

At  first  the  embryo  appears  to  be  only  a  semi-liquid  vesicle,  and  to  consist  of  minute 
globules  disseminated  through  a  more  fluid  medium,  which  presents  an  oval  or  spheroid 
form.*  As  the  embryo  advances,  the  proportion  of  solid  matter  increases,  and  continues 
to  increase  to  the  termination  o.f  the  life  of  the  individual.  The  h'rsjt  stage  of  its  exist- 
ence resembles  that  oi'  the  polypus ;  and  the  globules  which  may  be  observed  in  its 
otherwise  homogeneous  texture,  closely  resembles  those  which  are  observed  in  the 
nervous  system.  At  first  the  embryo  is  colourless ;  it  afterwards  presents  a  gradual  de- 
velopment of  colour,  and  at  last,  a  coloured  fluid  may  be  discerned.  From  a  state  of  or- 
ganization, consisting  merely  of -disseminated  globules,  fibres,  membranes,  and  vessels, 
come  Successively  into  existence.  The  organs,  as  we  have  already  said,  are  not  formed 
at  once  :  they  are  gradually  developed.  Even  particular  systems  do  not  assume  at  once 
their  form  of  organization,  but  are  developed  by  degrees,  and  run  through  the  same 
stages  of  organization  as  may  b$  remarked  in  the  animal  scale.  This  is  particularly  re- 
markable, ss  respects  the  development  of  the  nervaussystem.f  (&ee  the  note  on  this 
subject. ) 

The  exterior  form  of  the  fetus  seems  to  be  assumed  before  its  tissues  attain  any  conside- 
rable degree  of  consistence.  The  glandular  viscera  are  at  first  formed  in  isolated  parts.  The 
globules  of  the  nervous  system  first  appear ;  these  become  united  into  cords  and  gan- 
glia, t  The  vessels  commence  in  isolated  vesicles,  which  become  elongate^  and  connected 


*  Mr.  Bauer  says  that  he  has  detected  the  human  ovum  on  the  eighth  day  from  co- 
ition. It  consisted  of  two  membranes ;  the  external  one  open  throughout  its  length, 
but  with  its  edges  turned  inwards,  like  the  shells  of  the  g-enus  voFuta  ,•  the  internal 
membrane  pointed  at  one  end  and  obtuse  at  the  other,  slightly  contracted  in  the  mid- 
dle, and  containing  a  slimy  fluid  and  two  vesicles. 

f  It  would  appear  that  in  the  process  of  the  growth  of  the  embryo,  even  of  man? 
that,  during  the  first  days  of  its  existence,,  the  nervous  system  can  only  be  traced  as  it 
exists  in  the  polypi ;  its  globules  seem  dispersed  through  the  embryal  structure  :  as 
the  ovum  advances  the  ganglial  branches,  and  the  ganglia  themselves  make  their  ap- 
pearance. 

-t  Viewing  the  nervous  system  throughout  the  numerous  classes  of  animals,  and 
tracing  the  process  of  its  formation  from  the  embryo  up  to  the  period  of  perfect  fatal 


88  APPENDIX. 

uf  regular  series.  Tlte  intestinal  tube  seems  to  be  the  viscus,  which  first  presents  a  defihitfi 
conformation.  It  is  at  first  straight,  and  afterwards  it  curves  forwards,  and  is  embraced  by 
the  umbilical  chord  :  it  thus  forms  an  angle  and  descends  into  the  abdominal  cavity,  which 
is  open  at  its  anterior  aspect,  and  apparently  continuous  with  the  short  and  imperfectly  de- 
veloped chord.  This  turn  of  the  intestinal  canal,  and  its  retention  in  the  chord,  seems  to 
form  the  umbilical  vesicle,  and  the  subsequent  strangulation  of  the  intestine  by  the  constric- 
tion and  elongation  of  the  chord  first  gives  rise  to  an  insulated  appearence  of  this  vesicle  sub- 
sequently, to  its  entire  disappearAce,  and  lastly,  to  the  separation  of  the  intestines;  tlie 
vermiform  appendix  remaining  as  a  type  of  the  original  conformation. 

About  the  same  time  that  the  intestinal  tube  curves  into  the  umbilical  chord,  the  urina- 
ry bladder  seems  to  be  also  prolonged  into  the  chord,  between  the  chorion  and  amnion, 
forming  the  allantois  and  urachus,  the  former  of  which  disappears  as  the  fa-tus  is  developed 
and  the  chord  lengthened,  the  urachus  only  remaining  at  the  time  of  birth,  showing  the 
nature  and  type  of  the  original  conformation  and  the  communication  formerly  existing  be- 
tween the  allantois  and  bladder. 

We  have  already  said  that  all  the  phases,  through  which  the  human  embryo  passes  until 
its  conformation  is  perfected,  correspond  with  the  different  stages  of  permanent  organiza- 
tion which  characterize  the  animal  scale.  Since  these  observations  were  made,  we  perceive 
that  a  similar  opinion  has  been  lately  entertained  by  J.  F.  Meckel,  and  adopted  by  M.  Be- 
clard,  in  his  recent  and  excellent  work  on  General  Anatonvy.  Many  proofs  may  be  addu- 
ced in  support  of  this  doctrine:  so  evident  indeed  is  the  analogy  that  a  very  close  parallel 
may  be  drawn  between  the  stages  of  development  through  which  the  human  foetus  passes, 
and  the  degrees  of  animal  organization. 

The  human  embryo  is  at  first  an  imperfectly  formed  vesicle  ;  such  are  the  polypi  and 
others  of  the  Zoophytes.  At  a  remoter  period  it  consists  of  a  small  vermiform  body 
without  a  distinct  head,  ov  limbs  ;  sftch  are  the  Echinodermata,  and  the  Annelides.  At  a 
still  later  period  its  limbs  ;  are  equally  developed,  and  its  tail  is  prominent:  such  are  the 
Quadrupeds. 

As  respects  the  nervous  system,  the  ganglial  or  vital  nerves  first  appear  with  their  gan- 
glions :  such  is  the  nervous  structure  of  the  invertebrated  animals.  As  the  embryo  advan- 
ces, the  ganglial  nerves  give  rise  to  two  thin  strips  of  medullary  matter  in  the  situation  of 
the  spinal  canal,  these  increase,  coalesce,  form  the  spinal  and  cervical  marrow,  (medulla 
oblongata)  and  the  tubercles  of  the  latter,  whence  are  produced  the  brain  and  cerebellum; 
we  observe  the  same  conformation  in  reptiles,  fishes,  &c. 

The  human  foetus  is  remarkable  for  the  rapidity  with  which  it  runs  through  the  early 
grades  of  the  scale  of  organization.  It  is  this  circumstance  that  renders  the  early  changes 
which  it  experiences  so  difficult  to  be  recognised. 


II.  Of  the  circulation  of  the  Fcetus.— There  are  abundant  facts  to  prove  that  the  circu- 
lation of  the  foetus  is  independent  of  that  of  the  mother;  that  the  blood  of  the  former  flows 
from  the  umbilical  arteries  into  the  vein  of  the  same  name,  and  not  from  the  uterine  arteries 
into  that  vein;  that  the  foetal  blood  is  fabricated  by  the  foetus  itself,  from  the  juices  furnish- 
ed by  the  mother  to  the  placenta,  and,  consequently,  that  the  foetus  (toes  not  receive  one 
drop  ready  formed  from  this  organ  by  the  umbilical  vein.* 


existence  in  the  perfect  animals^  especially  in  man,  we  are  led  to  infer  that  this  system 
is  not  originally  formed  from  the  centre  towards  the  circumference,  but  that  the  origin 
of  its  ramifications  commences  in  the  mucous  or  cellular  tissue,  when  the  embryo  is 
yet  but  in  an  apparently  homogenious  state ;  and  that  as  the  textures  become,  in  the 
process  of  foetal  growth,  more  and  more  developed,  so  the  globules  composing  the 
nervous  system,  and  chiefly  those  of  the  g'anglial  System  of  nerves  are  arranged  into 
cords  of  communication,  chiefly  in  the  course  of  the  vessels,  for  the  purpose  Of  pre- 
serving communication  between  the  organs,  and  reinforcing  each  of  the  textures  with 
the  influence  which  they  generate  in  their  perfect  state  of  development.  As  the  pro- 
cess of  foetal  growth  proceeds,  the  nervous  ramifications  advance  towards  centres, 
which  vary  in  their  characters,  according  to  the  species  of  the  animal ;  in  those  which 
are  more  perfect  those  centres  are  numerous,  and  almost  each  differs  in  a  more  or  less 
sensible  manner  from  the  other,  both  as  to  appearance  and  function. 

*  D.  F.  Lavagna  concludes  that  the  menstrual  blood  differs  from  common  blood,  only 
in  containing  no  fibrin  ;  also,  that  the  blood  in  the  uiribilical  arteries  of  the  funis  contains 
scarcely  any  fibrin,  whilst  that  in  the  umbilical  vein  forms  a  tenacious  jelly;  hence,  he  in- 
fers, that  the  blood  acquires  fibrin  in  the  ciculation  in  the  placenta,  which  it  parts  with  in 
its  passage  through  the  foetus — Annali  di  Medicina  di  Milwio,  JVo.  17. 


ON  THE  DEVELOPMENT  OF  THE  FCETL'S.  £9 

la  proof  of  the  correctness  of  this  opinion,  we  may  refer  to  the  experiments  performed  by 
M.  Gaspard,  (Jourtt.  de  Physiul.  Experiment,  No.  3,)  in  order  to  ascertain  this  point,  and 
to  the  formation  of  blood  in  the  impregnated  egg  on  the  second  or  third  day  after  incuba- 
tion, and  to  the  fact  that,  in  the  numerous  tribe  of  oviparous  animals,  the  foetuses  are  insu- 
lated from  the  mother,  and  are  the  real  manufacturers  of  their  own  blood. 

At  an  early  period  of  fcctal  life  the  ganglial  ramifications  and  centres  are  first  formed, 
and  afterwards  the  ramifications  and  centres  of  the  voluntary  nerves.  In  the  more  perfect 
animals,  even  that  part  of  the  nervous  system  which  is  general  throughout  the  animal  crea- 
tion, and  which  the  lowest  orders  of  it  possess,  is  the  first  formed,  and  that  part  which  is 
destined  to  perform  the  highest  functions,  and  which  the  perfect  animals  only  possess,  is 
produced  the  last. 

Other  peculiarities  of  the  fcetus  are  adduced  in  the  subjoined  notes: — 


Of  the  Development  of  the  Heart  and  Ltaigs. — J.  F.  Meckel  has  concluded  from  his  ob- 
servations, 1st,  The  heart  is  relatively  larger  the  younger  the  embryo.  For  in  his  observa- 
tions he  found,  at  the  first  period,  at  which  the  heart  could  be  distinguished,  that  it  filled 
completely  the  thoracic  cavity. 

2d,  The  heart  is  more  symmetrical  with  respect  to  situation  and  form,  soon  after  its  for- 
mation, than  at  a  more  remote  period. 

3d,  The  form  of  the  heart  undergoes  various  changes  during  the  growth  of  the  ftetus. 

Jl.  The  proportion  between  the  arterial  and  venous  portions  of  the  heart  is  not  always 
the  same.  The  auricles  surpass  the  ventricles  in  capacity,  in  proportion  as  the  embryo  is 
younger. 

.B.  The  relative  volume  of  the  two  sides  of  the  heart  is  not  always  the  same  at  all  pe- 
riods. In  the  adult  the  right  side  always  more  or  less  exceeds  the  left;  but  in  very  young 
embryos  the  two  ventricles  are  equally  capacious,  but  that  of  the  right  side  increases  ra- 
pidly. The  right  auricle  surpasses  the  left  in  size  in  the  foetus,  and  it  is  only  by  degrees 
that  the  left  becomes  equal  to  the  right. 

C.  The  right  ventricle  is  unquestionably  smaller  than  the  left  at  first. 

D.  The  thickness  of  the  parietes  of  the  heart  is  much  more  considerable  at  first.     The 
two  halves  of  the  heart  equally  present  this  difference,  but  the  right  ventricle  always  ap- 
pears a  little  thicker  than  the  left.     This  is,  however  less,  the  younger  the  foetus. 

-B.  The  two  ventricles  communicate  with  each  other  at  an  early  period,  and,  according 
to  all  appearances,  continue  to  do  so  until  the  end  of  the  second  month,  by  means  of  an 
opening  in  their  interior  aspects,  situated  at  their  base,  and  immediately  beneath  the  origin 
of  the  great  vessels. 

F.  The  interior  disposition  of  the  auricles  with  respect  to  their  communication,  either 
with  one  another,  or  with  the  venous  trunks,  undergoes  considerable  changes.  These  turn 
chiefly  on  the  form  and  size  of  the  oval  hole,  the  situation  of  the  orifice  of  the  vena  cava 
inferior,  the  situation,  the  form,  the  extent  and  relations  of  the  valve  of  Eustachius  and 
thit  of  the  foramen  ovale.  Here  M.  Meckel's  researches  confirm  those  of  Sabatier  and 
Wolff. 

1th,  The  disposition  of  the  aorta  and  of  the  pulmonary  artery  offers  several  considerable 
changes,  in  succession,  of  which  the  following  are  the  chief. 

A.  At  first  there  exists  only  an  aorta.     A  pulmonary  artery  is  formed  at  a  remoter  pe- 
riod.    It  is  not  until  after  the  seventh  week  that  the  pulmonary  artery  begins  to  appear, 
and  then  it  is  only  a  second  aortic  trunk,  as  yet  without  branches — a  right  aorta,  proceeding 
in  the  direction  of  the  lungs,  which  are  very  distant,  and  extremely  small. 

The  disposition  of  tLe  large  arteries  at  this  period  (seventh  week)  nearly  resembles  what 
it  Continues  to  be,  in  reptiles,  during  the  \vhole  life  of  the  animal. 

B.  It  is  in  the  course  of  the  eighth  week  only,  in  which  the  branches  of  the  pulmonary 
artery  can  be  discovered.     They  are  then  much  smaller,  when  compared  to  the  trunk  of 
the  artery  and  to  the  arterial  canal,  the  younger  the  embryo.     At  five  months  they  become 
equal  to  this  canal,  and  afterwards  they  surpass  it,  frequently  so  far  that  when  the  fcetus 
has  completed  the  ninth  month,  each  principal  branch  of  the  pulmonary  artery  is  as  large 
as  it  is,  or  even  larger. 

The  venous  canal  presents  similar  appearances.  It  is  during  the  first  periods  of  the  ex- 
istence of  the  fetus  when  it  offers,  proportionally,  the  greatest  amplitude.  All  the  obser- 
vations which  M.  Meckel  has  made,  confirm  this  law,  which  is  the  more  important  as  it 
throws  considerabie  light  on  the  functions  of  this  canal.  Indeed,  it  is  probable  that  this 
conformation  is  only  the  remains  of  a  disposition  which  may  be  seen  at  the  epoch  when  the 
liver  has  not  come  into  existence,  when  the  vena  porta  and  the  vena  cava  inferior  form  but 
one  trunk,  as  the  pulmonary  artery  forms,  at  the  early  stage  of  its  existence,  only  one  with 
rta.  This  conjecture  respecting  the  origin  of  the  venous  canal  is  confirmed  by  the  or- 


i^j  APPENMX 

ganization  of  the  acephalous  class  of  animals,  in  which  the  veins  of  the  intestinal  cana'i, 
and  Consequently  the  vena  porta,  also,  open  immediately  into  the  vena  cava  inferior. 
5th,  The  lungs  are  not  formed  until  a  more  advanced  period. 

In  man,  manifest  traces  of  them  cannot  be  seen  before  the  sixth  or  seventh  week.  Then 
they  advance  beneath  the  heart,  at  the  two  sides  of  the  inferior  extremity  of  the  pectoral 
portion  of  the  aorta.  At  the  period  of  their  appearance,  and  even  for  some  time  afterwards, 
they  are  so  small,  in  proportion  to  the  heart  and  the  other  organs,  that  it  requires  the  great- 
est attention  in  following  their  progressive  development,  to  be  convinced  that  they  are  ia 
reality  the  rudiments  of  the  respiratory  organ. 

At  first  the  lungs  closely  approach  one  another:  they  are  flat  and  of  a  whitish  colour. 
Their  surface  is  perfectly  united  ;  but,  on  their  external  border,  may  be  observed,  at  an 
early  period,  indentations,  which  are  the  traces  of  the  approaching  separation  of  the  lobes, 
notwithstanding  that  these  lobes  are  not  yet  in  existence.  At  a  farther  advanced  period 
the  lobes  appear  to  be  composed  of  lobules.  These  latter  are  at  first  larger  and  much  less 
numerous,  in  proportion,  than  at  subsequent  periods,  but  they  separate  by  degrees  into 
others  much  smaller.  At  the  period  when  they  are  first  observed,  they  are  as  much  more 
apparent,  and  as  much  less  intimately  united,  by  cellular  tissue,  as  the  embryo  itself  is 
younger. 

6th,  As  the  lungs  become  developed,  in  the  reptiles  and  leeches,  in  the  form  of  an  empty 
sack,  it  is  natural  to  suppose  that  their  production,  in  animals  of  a  higher  order,  takes  place 
according  to  the  same  manner  and  law.  M.  Meckel  endeavoured  to  ascertain  whether  or 
no  this  was  actually  the  case.  But,  under  whatever  aspect  he  viewed  the  lungs  at  the  ear- 
ly stages  of  their  formation,  even  with  the  assistance  of  the  microscope,  he  always  found 
the  slices  which  were  removed  from  them  completely  solid;  if  they  are  really  so  during  this 
epoch,  it  would  seem  as  if  they  had  some  analogy  of  structure  with  the  Branchiae  of  fishes. 
7th,  The  branches  of  the  pulmonary  artery,  which  proceed  from  the  right  or  pulmonary 
aorta,  are  at  first  certainly  wanting.  It  must  therefore  be  admitted  that  at  this  epoch, 
their  places  are  supplied  by  the  bronchial  arteries,  especially  by  the  inferior,  since  the  lungs 
are  at  first  placed  low  in  the  inferior  part  of  the  chest.  Moreover,  this  depending  situation 
of  the  respiratory  organ,  at  the  •commencement  of  its  development,  is  remarkable  under  two 
points  of  view: 

Jl.  Since,  amongst  reptiles,  and  many  of  the  mammiferi,  the  lungs  are  placed  much  lower 
than  in  man,  and  below  the  heart,  in  every  respect  like  the  fishes,  the  swimming  bladder 
is  placed  below  this  organ. 

B.  Because  it  seems  that  the  lungs  and  the  thymus  gland  correspond  in  their  functions, 
the  development  of  the  one  being  in  direct  proportion  to  the  decrease  of  the  other. 

L  F.  Meckel  concludes  from  the  researches  of  which  we  have  given  an  abridged  outline, 
that  the  general  results  confirm  it  to  be  a  grand  law  of  the  animal  economy,  that  the  em- 
bryo, from  the  instant  of  its  formation  until  that  of  its  maturity,  rises  successively  through 
many  inferior  grades  of  organization,  and  that  the  principal  monstrosities  of  the  heart  and 
large  blood-vessels  depend  upon  these  organs  being  arrested  at  some  one  grade  or  degree  of 
organization,  instead  of  following  the  progress  of  the  others  towards  perfection. 

Respiration  of  the  Foetus. — The  thymus  gland  appears  to  assist  the  placenta,  the  liver, 
and  the  secretion  cf  fat,  in  the  respiration  of  the  foetus,  or  rather  in  purifying  the  blood  of 
the  foetus.  It  seems  to  form  a  nidus  for  the  reception  of  those  elements  of  the  blood— ^-car- 
bon and  hydrogen,  which  are  secreted  in  a  state  approaching  to  fat,  and  which  if  too  abun- 
dant in  this  fluid,  would  endanger  the  existence  of  the  foetus.  These  materials  on  the  com- 
mencement of  active  respiration  are  again  absorped,  to  be  discharged  from  the  economy  by 
the  lungs,  liver,  or  intestinal  canal.  The  thymus  gland  in  the  human  foetus,  in  the  ninth 
month,  generally  weighs  from  160  to  180  grains;  at  28  years  of  age  only  90  grains. 
In  the  calf  it  weighs  16  ounces,  in  the  cow  9  ounces. 

*'  Etenim  placenta,  hepar,  adipis  aucta  secretio  respirationi,  sed  aliud  aliomodo,  inser- 
viunt.  Quoe  naturre  institutio,  ut  in  foetu  organon  alterum  alterius  vices  obtinere  possit, 
pulcherrima  et  prsestantissima;  quo  fit,  ut  foetus  vita  nondum  autonomica,  a  noxiis  qtiibus- 
cunque  momentis,  quae  vim  in  ipsum  habere  possunt,  tueatur  conserveturque,  donee  ex 
asylo  matris  in  lucem  aeremque  editus  vim  innatam  exerceat. 

Vena  umbilicalis  illo  principio  (oxygenio)  gravida  partim  in  hepar,  partim  in  venam  ca- 
vam  inferiorem  sanguinem  reducit  a  partibus  phlogisticis  liberatum.  Itaque  vepa  cava  in- 
ferior, postquam  sangninis  partem  ex  vena  umbilicali  et  venis  hepaticis  excepit,  prater  san- 
guinem oxydatum,  venosum  quoque  sanguinem  ex  corporis  partibus  reducem  continet,  cujus 
tamen  pars  satis  magna,  sanguis  lienalis  ac  meseraicns,  in  hepate  jam  carbone  relicto,  mera 
existit.  Quoniam  vero  vena'  cava  inferior  prima  vitae  foetalis  parte  magis  in  sinistrum  quam 
in  dextrum  cordis  atrium  aperitur,  sanguis  autem  venre  cavae  superioris,  nil  minus  quam 
oxygenium  ducens  ex  dextro  cordis  atrio  per  arteriam  pulmonalera,  hinc  per  ductum  Botal- 
licura,  demum,  postquam  jam  arteriac  superiorum  partlum  ex  aorta  oxcreverun1-,  in  ipsaia 
perfunditur;— -sequitur  caput  atque  extremitates  superiores  sanguinem  magis  oxydaturn, 
sen,  si  mavis,  dephlogisticatum,  in  atrio  sinistro  ventriculcque  congestum,  accipere: — aor- 


,iE  MORTALITY  OF  KKMAL1IS. 


Of  the  Varieties  of  the  Human  Specif  ^ 
Note  L.  L. 

BufFon,  Blumenbach,  Prichard.  Gavoty  and  Touluzan,  Cuvier,  and  others,  have  propos- 
ed classifications  of  the  varieties  of  the  human  species:  of  these  we  prefer  that  of  Cuvior. 
The  following  is  an  outline  of  it: — 

1st,  The  fair,  or  Caucasian  variety;  2d,  the  yellow,  or  Mongolian;  3d,  the  negro,  or 
Ethiopian. 

1st,  CAUCASIAN.  Characters.  The  beautiful  form  of  the  head,  the  variable  shades  of 
complexion,  and  colour  of  the  hair.x 

Principal  Branches.  1,  The  Syrian,  whence  have  proceeded  the  Assyrians,  the  Chal- 
deans, the  Arabs,  Phoenicians,  Jews,  the  Abyssinians,  Arabian  colonies,  and  ancient  Egyp- 
tians. 2,  The  Indian,  German,  or  Pelasgic  branch  was  early  subdivided  into  the  Sanscrit, 
the  Pelasgi,  the  Teutonic,  and  Sclavonian.  3,  The  Scythian,  or  Tartarian  branch. 

2d,  MONGOLIAN.  Characters.  Prominent  cheek-bones;  flat  visage;  narrow  and  oblique 
eyes;  straight  and  black  hair;  scanty  beard,  and  olive  complexion.  Its  civilization  has  al- 
ways remained  stationary. 

3d,  The  NEGRO.  Characters.  Black  complexion;  woolly  hair;  compressed  cranium,  and 
flattish  nose. 

"  It  is  very  difficult  to  refer  the  Malays,  or  the  Papuas,  to  any  one  of  the  three  great  va- 
rieties of  mankind  already  described.  It'is  a  question";  however,  whether  the  former  people 
can  be  accurately  distinguished  from  their  neighbours  on  either  side:  the  Caucasian  Hin- 
doos on  the  one,  and  the  Mongolian  Chinese  on  the  other. 

"  The  Americans  themselves  have  not  yet  been  properly  referred  to  either  of  the  other 
races,  nor  have  they  characters  precise  and  constant  enough  to  constitute  a  fourth  variety. 
Their  copper-coloured  complexion  is  not  sufficient.  The  black  lank  hair,  and  scanty  beard, 
•would  seem  to  approximate  them  to  the  Mongoles,  if  their  well  defined  features,  and  pro- 
minent noses,  did  not  oppose  such  a  classification;  their  languages  are  likewise  as  innume- 
rable as  their  tribes,  and  no  mutual  analogy  has  yet  been  ascertained  between  them,  nor 
any  affinity  with  the  dialects  of  the  ancient  world.''  (Griffith.'' s  Tran-s.  of  the  Regne  Jlni- 
male.) 

We  are  inclined  to  infer  that  America  was  peopled  by  the  Mongoles  from  Asia;  and  that, 
subsequently,  it  had  been  visited  by  Phoenician  navigators:  the  greater  part  of  whom  set- 
tled in  it,  particularly  in  Mexico;  and  that  the  imperfect  navigation  of  that  era  prevented 
many  of  the  adventurers,  if  not  all  of  them,  from  returning. 


Of  the  Mortality  of  Females  at  the  Change  of  Lift 

,    From  the  bills  of  mortality  of  both  sexes,  collected  in  Provence,  Switzerland,  Pans,  Ber- 
lin, Sweden,  and  Petersburgh,  it  would  seem,  1st,  that  from  30  to  70,  no  other  increase  takes 


tam  vero  descendentemsanguinem  ex  vena  cava  superiori  phlogisticnm  nee  oxydatum  in 
abdomen  atque  extremitates  inferiores  perducere,  quo  fit,  ut  superiores  corporis  partes,  ex- 
ceptis  pulmonibus,  qui  sanguinem  ex  vena  cava  superiori  venientem  venosum  accipiunt, 
primo  graviditatis  tempore  magis  vigeant  polleantque.  p.  215. 

"  Placenta  oxygenium  afferente,  hepate  carbonium  submovente,  quae  functiones  in  adulto 
in  unopulmone  conjunctae  sunt."  p.  216.  (Joannis  Mueller  de  Re spiratione  Foetus  Commcn- 
tatio  Physiologica,  inAcademia  L^russica  Rhen,ana  Prccmio  Ornata.  Lipsic.  1828.  p.  159. 

M.  GeorTory-Saint-Hiolaire,  proceeding  on  the  principle,  that  there  cannot  be  organiza- 
tion without  the  combination  of  a  nutritious  fluid,  nor  yet  assimilation  without  oxygenation 
or  previous  respiration,  endeavours  to  show: — 1st,  That  a  respirable  gas  is  present  in  the 
amniotic  fluid,  as  shown  by  the  experiments  of  MM.  Chevreuil  and  Lassaigne:  2d,  That 
the  foetus,  by  means  of  its  pores,  as  by  so  many  tracheas,  in  the  same  manner  as  aquatic 
insects,  is  enabled  to  consume  the  air  contained  in  the  surrounding  fluid,  owing  to  the  air 
being  thus  brought  in  contact  with  the  venous  blood  which  fills  the  capillaries  of  the  skin  ; 
3d,  That  the  contraction  of  the  womb  and  of  the  abdominal  muscles  keeps  up  a  certain  de- 
gree of  pressure,  which  is  as  requisite  to  the  perfect  perforjnan"'1  of  this  process  ?.s  to  th^ 
ordinary  a^t  of  respiration  -- 7?r'».  Me?.  Her.  1R23, 


W  APPENDIX. 

place  in  the  mortality  oi  females,  than  what  naturally  results  from  the  progress  of  age;  2u, 
that  at  all  periods  of  the  life  of  man,  from  30  to  70,  a  greater  mortality  occurs  than  in  wo- 
men, but  especially  40  to  50.  (M.  Bcnoiston  de  Vhateauneuf  on  the  Mortality  of  Females 
from  10  to  50  Years  of  Age.  Paris,  1822.) 


Of  the  Signs  of  Death. 
Note  M.  M. 

This  subject  has  been  so  fully  and  ably  discussed  in  the  very  excellent  works  of  Dr.  Beck, 
of  Dr.  Gordon  Smith,  and  of  Dr.  Paris  and  Mr.  Foublanque,  on  Medical  Jurisprudence,  that 
•we  prefer  recommending  the  reader  to  consult  them  on  this  subject,  to  entering  imperfectly 
upon  the  topic  at  this  place,  our  limits  not  allowing  the  satisfactory  discussion  of  it 


93 


CHAPTER.  II. 

Chemical  constitution  of  the  Solids  and  Fluids  of  the  Human  Body. 

I.  Simple  substances  entering  into  the  Constitution  of  the  different  Animal  Principles 
or  Constituents  of  the  Human  Body. 

The  following  simple  substances  are  variously  combined,  in  order  to  produce  the  consti- 
tuent parts  of  the  body  : 

1.  Azote,  6.  Lime,  11.  Magnesia,  (Magnesium,} 

2.  Carbon,  7.  Sulphur,  12.  Silica, 
li.  Hydrogen,                      8.  Soda,  (Sodium,)          13.  Iron, 

4.  Oxygen,  !>.  Potass,  (Potassium,)  14.  Magnanese, 

5.  Phosphorus,  10.  Muriatic  Acid. 

Of  these,  magnesia  and  silica  may  be  considered  as  foreign  bodies  ;  they  being  seldom 
found,  and  in  exceeding  small  quantities.  The  principal  elementary  ingredients  are  the 
first  six:  animal  substances  may  be  considered  as  chiefly  composed  of  them.  The  first  four 
constitute  almost  entirely  the  soft  parts;  and  the  other  two  form  the  basis  of  the  hard  parts. 

II.  Animal  Constituents  or  Principles. 

I.  GELATIN  consists  of  Carbon,  47.88  ;  Hydrogen,  27.20;  Oxygen,  27.20;  Azote,  17.00; 
or  of  15,  14,  6,  2,  atoms  respectively.     Contained  in  skin,  bone,  tendons,  &c.     Test, 
Tannin. 

II.  ALBUMEN, — Corrosive  sublimate  detects  gViTo  Part  tlie  weight  of  the  water  contain- 
ed in  it.     COMP.— Carbon,  52.883  ;  oxygen,  23.872  ;  hydrogen,  7.540  ;  azote,  15.705,  in 
100  parts.     Dr.  Prout  found  it  to  consist  of  15  atoms  of  carbon,  6  of  oxygen,  14  hydrogen, 
2  azote,  according  to  the  analysis  quoted. 

III.  FIBRINE  varies  in  its  species  in  the  different  classes  of  animals.     COMP. — Carbon, 
53.360;  oxygen,  19.685;  hydrogen,  7.021;  azote,  19.934.    Consists  of  carb.  18  atoms,  oxyg. 
5,  hydrog.  14,  azote  3. 

IV.  COLOURING  MATTER  OF  THE  BLOOD. — Berzelius  found  it  possessed  of  nearly  the 
same  properties  as  fibrin.     It  is  soluble  in  water  at  a  low  temperature;  and  in  all  the  acids, 
except  the -muriatic,  contains  iron.     (Berzelius,  vol.  3.  Med.  Chirurg.  Trans.) 

V.  UREA,  or  NEPHRIN,  soluble  in  water  and  in  alcohol.    Precipitated  in  pearly  crystals 
by  nitric  acid  and  oxalic  acid.     Dissolved  by  a  solution  of  potass  or  soda. 

Oxygen,-  -  -  39.5)  2  atoms  Hydrogen,  -  -0.25-  -  -     6.66 

Azote,      -  -  -  32.5  I  1 Carbon,      -  -  0.75  -  -  -  20.00 

Carbon,    -  -  -14.7(1 Oxygen,     -  -1.00-  -  -26.66 

Hydrogen,  -  -  13.3  j  1 Azote,       -  -  1.75  -  -  -  46.66 

100.  3.75  100. 

(Dr.  Prout.') 

Gelatin  is  insoluble  in  cold  water,  albumen  is  insoluble  in  hot,  and  fibrine  is  insoluble  in 
both  cold  and  hot. 

The  constituents  of  these  three  bodies,  and  of  nephrin,  according  to  the  best  analysis  of 
them  hitherto  made,  are  as  follow  : 

Carbon.        Oxygen.         Hydrogen.         Azote. 
Gelatin,     atoms  15  -     -     -     -  6  -    -    -     -  14  -    -     -    -  2 

Albumen, 17  -     -    -     -  6  -     -    -     -  13  -     -     -    -  2 

Fibrine, 18  -     -     -     -  5  -     -    -     -  14  -     -     -     -  3 

Nephrin,  1--          -1-  -2----1 

The  colouring  matter  of  the  blood  approaches  albumen  in  many  of  its  properties  ;  but  it 
seems  entirely  destitute  of  azote. 

VI.  Mucus. — Insoluble  in  water,  transparent  when  evaporated  to  dryness,  and,  like 
gum,  soluble  in  the  acids.     Not  soluble  in  alcohol  or  ether — does  not  coagulate  by  heat — 
nor  is  precipitated  by  corrosive  sublimate,  or  by  galls.     Is  precipitated  by  the  acetates  of 
lead,  and  by  nit.  argenti.     Found  in  the  epidermis,  in  nails,  feathers,  &c.   (Bostock,  in  Ni- 
cholson's Journ.  XL  251.) 

VII.  OSMAZOMK  is,  probably,  only  an  altered  state  of  fibrine.     Soluble  in  water  and  al- 
cohol—does not  gelatinize.     Precipitated  by  nit.  argenti.  nit.  hydrarg.  and  acet.  and  nit.  of 
lead. 

VIII.  PIGROMEL — found  principally  in  bile  ;  resembles  inspissated  bile  in  its  appear- 
ance ;  soluble  in  water  and  in  alcohol  : 


APPENDIX, 


5  atoms  Carbon,    -     - 

1 Hydrogen,    - 

3 Oxygen,   •     - 


3.75  -    -    -     54.5S 
1.25  -    -    -      1.82 
3.000  -     -    -     43.65 

(Dr.  Thomson,  An.  Ph.  14.  69.) 
IX.  SUGAR  OF  MILK,  according  to  Berzelius,  consists  of  oxygen,  53.359  ;  carbon , 
39.474  ;  hydrogen,  7.167.     (Annals  of  Philos.  5.  266.) 

Dr.  Thomson  gives  the  table  of  the  atomic  analysis  as  follows  : 
4  atoms  Oxygen,     -     -  4         -     -     -  48.4 

5 Carbon,     -    -  3.75    -    -     -  45.4 

4 Hydrogen,     -  0.50   ...    6.2 


8.25  100.0 

X.  OILS  are  fixed. — Fat — Cholesterine. — The  former  is  composed  of  oxygen,  hydrogen, 
and  carbon.    The  latter,  according  to  Saussure,  consists  of  84.068  of  carbon  ;  12.672  of  hy- 
drogen ;  and  3.914  of  oxygen  ;  and  differs  little  from  the  other  fixed  animal  oils,  excepting 
that  it  contains  more  carbon  and  less  oxygen  than  they. 

XI.  ACIDS. — The  acids  found  constituting;  and  ready  formed  in  animal  bodies  are  the 
following  : 

1.  Phosphoric,  6.  Uric,  11.  Acetic. 

2.  Sulphuric,  *7.  Rosacic,  12.  Malic, 

3.  Muriatic,  8.  Amniotic,  13.  Lactic, 

4.  Carbonic,  9.  Oxalic,  14.  Silica. 

5.  Bcnzoic,  10.  Formic, 

It  may  be  remarked  that  the  whole  of  the  soft  parts  of  animals  consist  chiefly  of  albu- 
men, fibrine,  and  oils  ;  and  the  hard  parts  of  phosphate  of  lime.  The  other  animal  princi- 
ples are  only  in  small  quantities,  and  in  particular  textures.  The  oils  seldom  enter  into  the 
structure  of  the  organs  of  animals,  they  serve  rather  to  lubricate  the  different  parts,  and  to 
fill  up  interstices. 

III.  Individual  Textures  and  Fluids  of  the  Human  Body  (formed  of  two  or  more  oj 
the  foregoing  Constituents.) 

The  Constituents  of  the  BONES  and  TEETH  of  some  of  the  Mammalia,  according  to  the 
Analyses  0/"  BERZELIUS  and  other  Chemists. 


f  •  

SB«O 

"**  " 

o 

~ 

'     * 

*?    \ 

»  5'??  ^ 

n  o. 

3* 

2 

c 

8 

p  a  *  F 

1"^ 

g 

f 

re 

H^ 

Substances  analyzed. 

fffj 

SP 
2,5= 

o 
"-•J 

1 
o 

s, 

s 

|l 

3  "  »  ~ 

»  o 

1 

r: 
P 

c' 
§ 

1 

Human  bones  recently  dried, 

33.3 

1.2 

11.3 

51.4 

2.0 

1.16  j 

Bullock's  bones  recently  dried, 

33.3 

2.45 

3.85 

55.45 

2.9 

2.05 

Osseous  parts  of  human  teeth, 

28.0 

1.4 

5.3 

61.95 

2.1 

1.25 

Osseous  parts  of  bullock's  teeth 

31.0 

2.4 

1.38 

57.46 

5.69 

2.07 

The  enamel  of  human  teeth, 

2.0 

— 

8.0 

85.3 

3.2 

1.5    j 

The  enamel  of  bullock's  teeth, 

3.56 

1.4 

7.1 

81.0 

4.2 

3.0    j 

The  compact  and  cellular  substances  of  human  bones  are,  according  to  Berzelius,  of  the 
same  composition. 


Forms  the  lateritious  sediment  in  fevers,  &c. 


OF  BONES  AND  TEETH,  & 


Substances  submitted  to 

analysis. 

0 

I 

1  Phosphate  of  mag- 
nesia. 

= 

2, 

a 

1. 
j  Phosphate  of  lime. 

1! 

o 

S 

2, 

to 

r 

Recent  bullock's  bones, 

51.0 

1.3 

— 

37.7 

10.0 

— 

Vauque- 
lin&Four- 
croy. 

A  child's  first  teeth, 

20.0 

— 

— 

62.0 

6.0 

12 

(6 

i  Teeth  of  an  adult, 

20.0 

— 

— 

64.0 

6.0 

10 

!  The  roots  of  the  teeth, 

28.0 

— 

— 

5S.O 

4.0 

10 

|  The  enamel  of  teeth, 

— 

— 

— 

78.0 

6.0 

16 

j  The  spine,  softened  by  disease, 

79.75 

0.82 

4.7 

13.6 

1.13 

— 

Bostock  j 

Fourcroy  and  Vauquelin  could  not  discover  the  fluate  of  calcium  either  in  the  enamel  of 
the  teetli  or  in  recent  ivory. 

Boiling  water  extracts  slowly  the  cartilage  of  bone  in  the  form  of  gelatine.  Cold  hydro- 
chloric acid  dissolves  the  salts  which  have  lime  for  their  base,  leaving  nearly  altogether 
untouched  the  whole  of  the  cartilage.  Ammonia  precipitates  the  phosphate  of  lime  from 
its  solution  in  warm  hydrochloric  acid  :  the  phosphate  of  lime,  however,  thus  obtained,  is 
accompanied  with  a  considerable  proportion  of  gelatine.  Bones,  submitted  to  dry  distilla- 
tion, give  gelatine,  and,  as  a  residue  the  carbon  of  bones,  which  is  a  compound  of  animal 
charcoal  and  the  salts,  with  potash  for  their  base:  exposed  to  the  air,  the  charcoal  of  bones 
passes  into  the  state  of  ashes. 

Tophus,  found  in  the  articulations  of  the  arm,  consists  of  animal  matter,  with  traces  of 
adipocire,  56.2  ;  carbonate,  phosphate,  and  hydrochlorate  of  potash,  3.2  :  carbonate  of 
lime,  with  traces  of  the  carbonate  of  magnesia,  12.5  ;  phosphate  of  lime,  28.1.  Another 
specimen  contained  animal  matter,  with  unctuous  and  fatty  matter,  and  a  little  soda,  73.0  ; 
carbonate  of  lime,  10  ;  phosphate  of  lime,  17.  (John  Ecrits  Chim.  v.  104.) 

The  concretions  found  in  persons  subject  to  the  gout  are  composed  of  the  urate  of  am- 
monia. (Wallaston.) 

The  marrow  of  bones.  The  medulla  of  the  cylindrical  bones  of  the  bullock  contain 
membranes  and  vessels,  1  ;  fat,  96  ;  a  reddish  serum,  3. 

The  medulla  of  the  lower  part  of  the  radius,  and  of  the  tibia,  contains  a  very  liquid  fat, 
and  neither  coloured  vessels  nor  membranes. 

The  diploe  of  the  extremities  of  the  long  bones  contain  fatty  matter  and  a  reddish  se- 
fum,  in  very  variable  proportions. 

The  rertebras  of  the  dorsal  column  contain  a  deep  brown  serum,  partly  concrete,  soluble 
in  water,  and  rarely  a  trace  of  fat.  (Bcrzelius,  JVbuv.  Journ.  de  Gehl.  ii.  287.) 

The.  cartilages  dissolve  in  water  kept  for  a  considerable  time  at  the  boiling  point,  and 
form  a  gelly. 

The  SYNOVIA  of  the  human  subject  consists  of,  a  yellowish  fat,  albumen,  which  consti- 
tutes its  chief  ingredient,  an  uncoagulable  animal  matter,  soda,  chlorate  of  potassium  and 
of  sodium  ;  and  the  ashes  furnish  carbonate  and  phosphate  of  lime.  (Lassaigne  and  Bois- 
sel,  Journ.  de  Pharm.  viii.  306.) 

The  synovia  of  the  articulations  of  the  knees  of  a  man  was  found  to  consist  of  a  floccu- 
lent  substance,  which  coagulated  at  the  temperature  of  boiling  water,  and  was  precipitated 
by  the  chlorate  of  mercury.  (Bostock.} 

Qout  appears  to  change,  in  some  degree,  the  secretion  in  the  joints  affected.  Dr.  Wol- 
laston,  Dr.  Pearson,  and  Mr.  Tennant,  found  the  chalk  stones  formed  in  this  disease  com- 
posed of  urate  of  soda.  Fourcroy  has  confirmed  this  analysis  ;  he  therefore  conjectures 
that  synovia  contains  uric  acid.  (Four.  ix.  224.) 

Synovia  of  a  horse. — A.  From  an  articulation  which  was  in  a  healthy  state  :  soluble  al- 
bumen 6.4  ;  animal  matter,  which  did  not  become  concreate,  with  the  carbonate  and  the 
hydrochlorate  of  soda,  O.G  ;  phosphate  of  lime,  0.15  ;  traces  of  an  ammonial  salt,  and  of 
phosphate  of  soda  ;  water  9.23. — B.  From  a  joint  ar.chylosed  in  consequence  of  a  wound  \ 


^5  APPENDIX. 

insoluble,  fibrous  albumen  ;  soluble  albumen  ;  free  phosphoric  acid  ;  the  same  salts  as  men* 
tioned  above.  (John  Ecrits  Chim.  vi.  146.) 

Synovia  of  an  elephant:  reddish,  filmentous,  of  a  slightly  saline  and  insipid  taste  ;  when 
warmed  or  heated  by  mineral  acids  it  coagulated.  It  contained  a  soluble  albumen  of  ani- 
mal matter  precipitated  by  tannin,  and  which  did  not  become  concrete,  in  a  small  quanti- 
ty ;  soda  and  hydrochlorate  of  potash.  ( Vauquclin,  Ann.  de  Chim.  et  de  Phys.  vi.  399.) 

The  periosteum  approaches  the  chemical  properties  of  cartilage,  and  yields  a  small  pro- 
portion of  gelatine. 

The  ligaments  resist  for  a  very  long  time  the  action  of  boiling  water,  but  dissolve  at 
last,  in  part,  fike  gelatine; 

The  membranes,  as  the  serous  (the  pia^mater,  arachnoid,  pericardium,  pleura,  peritone- 
um, &c.)  and  the  skin,  dissolve  in  boiling  water,  and  pass  to  the  state  of  gelatine. 

INTEGUMENT,  Cutis  vera — formed  of  fibres  interwoven  like  a  felt.  It  yields  little  gela- 
tin, on  maceration  in  cold  water  :  by  long  boiling  in  water  it  becomes  gelatinous,  and  dis- 
solves completely,  and  by  evaporation  it  becomes  glue.  Hence  it  appears  to  be  a  peculiar 
modification  of  gelatin.  By  tannin,  and  the  extractive  of  oak  bark  combining  with  it,  lea- 
ther is  formed. 

Rete  mucosum — "  is  a  mucous  membrane,  situated  between  the  cutis  vera  and  the  epi- 
dermis. The  black  colour  of  negroes  is  said  to  depend  upon  a  black  pigment  situated  in 
this  substance  ;  but  it  seems  to  us  to  be  situated  in  the  inner  or  flocculent  surface  of  the 
epidermis.  Chlorine  deprives  it  of  its  black  colour,  and  renders  it  yellow.  A  negro,  by 
keeping  his  foot  for  some  time  in  water  impregnated  with  that  gas,  deprived  it  of  its  colour, 
and  rendered  it  nearly  white  ;  but  in  a  few  days  the  black  colour  returned  again  with  its 
former  intensity.  (Fonrcroy,  ix.  p.  259.)  This  experiment  was  first  made  by  Dr.  Beddoes 
on  the  fingers  of  a  negro."  (Beddoes  on  Factitious  Airs,  p.  45.) 

The  epidermis  possesses  the  same  properties  as  horn.  The  internal  surface  of  the  epi- 
ilermis  seems- to  be  the  seat  of  the  black  colour  of  the  negro,  and  not  the  rete  mucosum. 
The  human  epidermis  consists  of — fatty  matter,  0.5  ;  animal  matter  soluble  in  water,  5.0  ; 
concrete  albumen,  93  to  95  ;  lactic  acid,  lactate,  phosphate,  and  hydrochlorate  of  potash, 
sulphate,  and  phosphate  of  lime,  an  ammonical  salt,  and  traces  of  iron,  1.  (John  Ecrits 
Chim.  vi.  92.)  The  nails  of  the  fingers  and  toes  present  an  analogous  constitution. 

HUMAN  HAIR  may  be  regarded  as  fine  tubes  of  a  substance  similar  in  all  its  properties 
to  horn,  covered  by  a  white  adipocire,  (probably  furnished  by  the  sebaceous  glands  of  the 
scalp)  and  filled  with  an  oily  matter,  which  is  either  of  a  greenish  black  colour,  red,  yel- 
low, or  nearly  colourless,  according  as  the  hair  is  black,  red,  yellow,  or  white.  The  ashes 
of  human  hair  is  composed  of  the  hydrochlorate  of  soda  ;  of  the  carbonate,  sulphate,  and 
phosphate  of  lime,  (and  the  phosphate  of  magnesia  in  that  which  is  white)  a  considerable 
portion  of  silicia,  oxide  of  iron  in  a  very  marked  proportion  in  black  hair,  but  scarcely  to 
be  recognised  in  that  which  is  white;  and  a  very  small  quantity  of  the  oxide  of  manganese. 

The  sulphur,  which  is  undoubtedly  combined  in  the  organization  of  the  corneous  or  horny 
substance,  is  found  more  abundantly  in  the  red  and  light  coloured  hair,  than  in  the  black. 

The  MUSCULAR  FLESH.  The  muscular  substance  is  probably  composed  of  very  little 
more  than  fibrine,  traversed  by  cellular  tissue  containing  fat,  by  the  aponeuroses  and  ten- 
dons, by  vessels  containing  blood,  by  lymphatics  containing  lymph,  and  by  nerves.  It  is, 
however,  very  probable  that  osmazome,  lactic  acid,  the  hydrochlorate  and  phosphate  of 
soda,  and  the  phosphate  of  lime,  particularly  belong  to  muscular  flesh,  although  they  are 
also  found  in  the  blood.  Cold  water  extracts  of  the  muscular  substances  the  red  colouring 
matter  of  the  blood,  the  albumen,  the  osmazome,  and  the  salts  of  the  blood  :  boiling  water 
takes  up  the  cellular  tissue  reduced  to  gelatine,  and  the  fat  which  swims  on  its  surface;  the 
residuum  consists  of  fibrine,  a  little  altered  by  the  boiling,  and  which  yields  the  phosphate 
of  lime  by  incineration.  The  muscular  substance  of  beef  gives,  by  incineration,  more  lime 
than  that  of  veal.  (  Hatchett. ) 

According  to  Berzelius,  the  muscular  texture  contains:  fibrine,  vessels,  and  nerves,  15.S; 
cellular  substance,  1.9  ;  albumen,  2.2  ;  osmazome,  with  the  lactate  and  hydrochlorate  of 
soda,  1.8  ;  mucous  matter,  0.15  ;  phosphate  of  soda,  0.9 ;  phosphate  of  lime,  containing  a 
portion  of  albumen,  0.08  ;  water  and  loss,  77.17. 

Bullock's  heart.  Osmazome,  7.57;  albumen  and  cruor,  2.76;  fibrine  with  vessels,  nerves, 
cellular  tissue,  fat,  and  phosphate  of  lime,  18.19  ;  an  ammonical  salt  and  a  free  acid  in  an 
indeterminate  quantity  ;  lactate  of  potash,  0.19  ;  phosphate  of  potash,  0.15  ;  c.hloruret  of 
potassium,  0.12  ;  water,  77.04.  (Bracounot  Jinn  de  Chim.  et  de  Phys.  xvii.  388.) 

An  ossification  found  in  the  human  heart.  It  contained  a  cartilaginous  matter  and  phos- 
phate of  lime  in  nearly  equal  proportions,  with  a  little  carbonate  of  lime.  (John  Ecrits 
Chim.  5.  159.) 

An  ossification  found  in  the  veins  of  the  human  uterus:  membranous  substance  and  phos- 
phate of  lime,  in  nearly  equal  quantities,  with  a  little  of  the  carbonate  of  lime  and  traces 
of  the  hydrochlorates.  (John,  ibid.  v.  126.) 


OF  BONES  AND  TEETH,  fcc.  ^7 

BRAIN  and  NERVES.  The  hemispheres  of  the  human  brain  :  a  reddish-brown  liquid  fat, 
leaving  phosphoric  acid  by  combination,  0.7  ;  a  white  fat  becoming  blacker  by  fusion,  and 
giving  rise  to  much  phosphoric  acid  by  combustion,  4.53  ;  phosphorus  contained  in  these 
fatty  substances,  1.5  ;  osmazome,  1.12  ;  albumen,  7.0  ;  phosphate  of  potash,  muriate  of 
soda,  phosphate  of  lime  and  phosphate  of  magnesia,  5.15  ;  water,  80. 

The  human  cerebellum  gave  the  same  results. 

Medulla  oblongata  and  spinal  cord  have  the  same  constituent  principles,  but  they  con- 
tain more  of  the  fatty  matter,  and  less  albumen,  osmazome,  and  water. 

The  nerves  of  the  human  subject  contain  less  of  the  liquid  and  chrystallizable  kinds  of 
fatty  matter,  but  more  of  the  fatty  substances  which  resembles  adipocire,  and  much  more 
albumen  than  the  brain.  (Vauquelin,  Ann  de  Chim.  Ixxxi.  37.) 

The  grey  substance  of  the  brain  of  a  calf  :  albumen  insoHible  in  water,  10.0  ;  an  unctu- 
ous incrystallizable  fat,  osmazome,  phosphate  of  ammonia,  phosphate  of  soda,  phosphate 
of  lime,  phosphate  of  magnesia,  hydrochlorate  of  soda  and  traces  of  iron,  15.0  to  10.0  ;  wa- 
ter 75  to  80. 

The  white  substance  of  the  brain  of  a  calf  contained  more  fatty  matter  than  the  grey  ;  it 
presented  traces  of  silicia.  The  cerebellum  of  the  calf  gave  the  same  products  as  the  cineri- 
tious  substance. 

The  optic  thalami,  the  medulla  oblongata,  spinal  marrow,  and  the  nerves  of  the  calf, 
gave  results  similar  to  those  furnished  by  the  white  substance  of  the  brain,  excepting  that 
they  contained  more  albumen  and  less  water. 

*  The  brain  of  a  bullock  contained  also  phosphate  of  ammonia,  a  more  solid  albumen,  a 
reddish  coloured  fat,  and  a  chrystallizable  fat.  The  composition  of  the  brain  of  the  stag 
was  similar.  (John  Ecrits  Chim.  iv.  249.  v.  162.) 

The  lymph  found  in  the  ventricles  of  the  human  brain:  gelatine  (osmazome  ?)  0.9  ;  mu- 
cus (salivary  matter  ?)  0.3  ;  albumen,  0.6  ;  hydrochlorate  of  soda  and  a  little  of  the  phos- 
phate of  soda,  1.5  ;  water,  96.5  ;  loss,  0.2.  (Haldat,  Ann.  de  Chim.  ex.  176.)  . 

A  soft  concretion  found  incysted  in  the  cerebral  pulp  of  a  subject  who  was  afflicted  with 
mental  alienation  :  white  grease^6  ;  semiconcrete  albumen,  17.0  ;  cartilaginous  substance, 
insoluble  in  potash,  18.0  ;  salts  with  ammonia,  potash,  soda,  and  lime  for  their  base,  about 
2.0  ;  water,  57.  (John  Scrits  Chim.  v.  102.) 

See  the  note  at  p.  207  and  208,  for  the  composition  of  the  *  humours  and  textures  of  the 
eye.'  The  pigmentum  nigrum  is  mixed  with  mucus. 

Mucus.  The  nasal  mucus  of  the  human  subject  contains  : — mucus,  5.33  ;  albumen,  and 
salivary  matter  with  a  trace  of  phosphate  of  soda,  0.35  ;  osmazome,  with  lactate  of  soda, 
0.3  ;  soda,  0.09  ;  hydrochlorate  of  potash  and  of  soda,  0.56  ;  water,  93.37.  (Berzelius, 
Fourcroy  and  Vauquelin.)  The  mucus  of  the  trachea,  according  to  Berzelius,  is  similar 
in  its  consumption. 

SALIVA.  Has  a  strong  affinity  for  oxygen,  absorbs  it  readily  from  the  air,  and  gives  it 
out  again  to  other  bodies.  The  human  saliva  consists  of — salivary  matter,  0.29  ;  mucus, 
0.14  ;  osmazome  with  lactate  of  soda,  0.08  ;  soda,  0.02  ;  hydrochlorate  of  potash,  and  hy- 
drochlorate of  soda,  0  17  ;  water,  99.29.  (Berzelius,  Bostock,  Thomson,  John.) 

Salivary  calculi  are  formed  of  a  membranous  substance,  containing  phosphate  of  lime. 

The  tartar  of  the  teeth.  Mucus,  1.25  ;  salivary  matter,  1.0  ;  animal  matter,  soluble  in 
hydrochlorate  acid,  7.5  ;  phosphate  of  lime,  and  phosphate  of  magnesia,  7.90.  (Berzelius.) 

The  LACHRYMAL.  FLUID.  Animal  matter,  soda  hydrochlorate  and  phosphate  of  soda, 
and  phosphate  of  lime,  1.0  ;  water,  99.0.  The  calculi  of  the  lachrymal  gland  are  formed, 
of  the  phosphate  of  lime.  (  Vauf>u 

The  GASTRIC  JUICE.  The  gastric  juice  ejected  by  vomiting  after  fasting  for  some  time 
resembled,  according  to  Montegre,  in  appearance,  the  saliva  ;  it  contained  flocculi  of  mu- 
cus, and  underwent  putrefaction  as  rapidly  as  the  saliva  ;  but  sometimes  it  was  acid,  and 
then  it  did  not  undergo  putrefaction. 

LYMPH  :  the  liquor  found  in  the  thoracic  duct  of  animals  which  have  not  taken  nourish- 
ment for  24  hours,  is  as  limpid  as  water,  does  not  affect  the  vegetable  colours,  does  not  co- 
agulate either  by  heat  or  by  acids  ;  it  becomes  slightly  turbid  from  alcohol,  leaves  a  very 
small  residuum  when  submitted  to  evaporation,  and  consequently  appears  to  contain  but* 
very  little  matter,  and  only  a  small  quantity  of  the  hydrochlorate  of  soda. 

The  lymph  of  a  horse  taken  from  the  thoracic  duct  towards  the  inguinal  region  and  me- 
^ocolon,  was  of  a  greenish  yellow,  translucid,  and  concreted  in  12  minutes  into  a  clear  ge- 
latine ;  the  coagulum,  which  hardly  amounted  to  pj-g-,  was  similar  to  fibrine,  the  fluid  con- 
tained about  0.04  of  albumen,  muriate  of  soda,  with  a  little  soda  and  phosphate  of  soda. 
(Reuss  andEmmert,  Journ.  de  Scherer,  v.  681.) 

CHYLE.     The  chyle  taken  from  the  thoracic  duct  of  a  dog,  three  hours  after  a  vegetable 

diet,  resembled  clear  milk,  and  deposited  a  reddish-white  coagulum  :  this  coagulum,  which 

had  the  appearance  of  fibrine,  was  to  the  serum  at  first  in  the  proportion  of  48  to  100  ;  but 

^eing  left  longer  to  itself  it  increased  considerably.    The  specific  weight  of  the  serum 


98  APPENDIX. 

was  1.018  ;  it  did  not  coagulate  at  the  temperature  of  boiling  water,  but  became  turbid  \ 
after  some  weeks  it  became  a  little  sour,  without  undergoing  putrefaction  :  in  100  parts  it 
contained  from  4.8  to  7.3  of  solid  matter,  which  consisted  of  0.9  of  soluble  albumen  and 
salts  ;  it  contained  neither  gelatine,  nor  phosphate  of  lime,  nor  any  ammoniacal  salt. 

The  chyle  of  a  dog,  collected  three  hours  after  having  eaten  meat,  had  the  appearance 
of  cream  :  its  coagulum,  a  little  red,  was  to  the  serum  at  first  as  46.5  to  100,  but  this  quan- 
tity diminished  gradually:  the  serum  became  much  more  turbid  by  heat  and  by  the  addition 
of  acids  than  that  produced  from  vegetable  food  ;  it  underwent  putrefaction  in  three  days  ; 
it  deposited  when  allowed  to  stand,  a  white  and  greasy  cream,  and  furnished  from  7  to  9.5 
per  cent,  of  solid  matter  consisting  of  soluble  albumen,  without  any  gelatine.  Brande  ob- 
served a  substance  analogous  to  the  sugar  of  milk  in  the  serum.  (Marcet,  Vauquclin, 
Brande ,  $r.) 

Chyle,  "  when  drawn  from  the  thoracic  duct,  about  five  hours  after  the  animal  has  ta- 
ken food,  is  an  opaque  liquid  of  a  white  colour  ;  without  smell,  and  having  a  slightly  acid 
taste,  accompanied  by  a  perceptible  sweetness.  The  presence  of  a  free  alkali  is  indica- 
ted. About  ten  minutes  after  it  is  drawn  from  the  animal  it  coagulates  into  a  stiff  jelly, 
which  in  the  course  of  twenty-four  hours  gradually  separates  into  two  parts,  producing  a 
firm  contracted  coagulum,  surrounded  by  a  colourless  fluid." 

1st.  "  The  coagulum,  as  appears  from  the  experiments  of  Vauquelin,  (Ann.  de  Chim. 
81  ;  113,)  is  an  intermediate  substance  between  albumen  and  fibrine.  He  considers  it  al- 
bumen on  its  way  to  assume  the  nature  of  fibrine.  It  is  not  so  stiff,  nor  of  so  fibrous  a  tex- 
ture as  fibrine  ;  it  is  more  easily  acted  on  and  dissolved  by  'caustic  alkalies.  It  is  insoluble 
in  alcohol  and  ether,  readily  dissolved  by  diluted  sulphuric  acid,  very  dilute  ;  nitric  acid 
converts  it  into  adipocire.  When  burnt  it  leaves  a  charcoal,  containing  common  salt,  phos- 
phate of  lime,  and  gives  traces  of  iron."  (Thomson.) 

2d.  The  liquid  portion  separates  albumen  on  boiling,  and  contains  sugar  and  a  very  small 
portion  of  a  fatty  matter,  similar  to  that  found  in  the  brain.  The  same  salts  as  in  other  ani- 
mal fluids. 

BJ.OOD.  Taste  slightly  saline,  smell  peculiar,  specific  gravity  1.0527.  As  soon  as  the  vi- 
tal influence  of  the  vessels  ceases  to  act  on  the  blood,  it  separates  into  the  coagulum  or 
cruor,  and  serum.  The  common  proportion  is  one  part  of  cruor  to  three  of  serum.  The 
proportion,  however,  varies  from  1.2  and  1.4.  If  the  separation  of  fibrine,  giving  rise  to 
the  coagulation,  takes  place  in  repose,  the  fibrine  entangles  the  red  particles  of  the  blood  j 
but  if  the  blood  be  kept  in  motion,  the  red  particles  escape  into  the  serum,  and  the  fibrine 
is  separated  into  threads. 

1st.  Serum.     Possesses  the  taste  and  smell  of  the  blood,  specific  gravity  is  about  1.0287. 

Berzelius  found  that  the  serum  of  human  blood  was  composed  as  follows: — water,  905.00, 
albumen,  80.00  ;  muriates  of  potash  and  soda,  6.00  ;  lactate  of  soda,  with  animal  matter, 
4.00  ;  soda,  phosphate  of  soda,  with  animal  matter,  4.10  ;  loss,  0.90  ; — 1000.00.  (Annals 
of  Philosophy,  ii.  202.) 

"Dr.  Marcet  found  the  constituents  of  serum  as  follows  :— water,  900.00  ;  albumen 
86  80  ;  muriates  of  potash  and  soda,  6.60  ;  muco-extractive  matter,  4.J00  ;  sub-carbonate  of 
soda,  1.65  ;  sulphate  of  potash,  0.35  ;  earthy  phosphates,  0.60.— 1000.  (Medico.  Chirurg 
Soc.  Transact,  ii.  376.) 

"  The  muco-extractive  matter  was  doubtless  impure  lactate  of  soda."  "  Berzelius  is  ot 
opinion,  that  the  sulphate  of  potash,  and  the  earthy  phosphates  which  were  found  by  Dr. 
Marcet  in  the  ashes  of  serum,  were  formed  during  the  incineration.  For  phosphorus,  sul- 
phur, and  the  basis  of  lime  and  magnesia,  exist  according  to  him  as  constituents  of  albu- 
men." 

"  Gelatin  was  considered  as  a  constituent  of  serum,  until  Dr.  Bostock  and  Professor  Ber- 
zelius have  sho\vn,  that  the  opinion  of  its  existence  in  blood  is  not  well  founded." 

2.  The  cruor,  or  the  clot.  Specific  gravity  about  1.245.  Is  separated  into  two  portions 
by  ablution  in  water.  1st,  A  white,  solid,  elastic  substance,  which  has  all  the  properties 
of  fibrine.  2d,  The  portion  held  in  solution  by  the  water  is  the  colouring  matter,  with  a 
portion  of  serum. 

•  "Berzelius  and  Brande  have  shown,  that  this  clot  is  a  compound  of  fibrine,  albumen,, 
and  colouring  matter  of  blood.  According  to  the  analysis  of  Berzelius,  it  consists  of — co- 
louring matter,  64  ;  fibrine  and  albumen.  36  ; — 100. 

"  When  the  colouring  matter  is  incinerated,  about  one-third  of  a  per  cent,  of  oxide  of 
iron  may  be  extracted  from  its  ashes.  This  portion  of  iron  is  a  constituent  of  the  colouring 
matter,  and  perhaps  the  cause  of  its  red  colour.  (Thorn,  iv.  492.)  But  in  what  way  it  is 
united  to  the  albuminous  portion  of  the  colouring  matter  remains  unknown.  When  incine- 
rated, the  colouring  matter  leaves  7V^  of  its  weight  of  ashes,  consisting  according  to  the 
analysis  of  Berzelius,  (which  appears  to  be  the  most  to  be  depended  on,)  of  the  following 
ingredients  : — oxide  of  iron,  50.0  ;  sub-phosphate  of  iron,  7.5  ;  phosphate  of  lime  with  tra- 
ces o.f  magnesia,  frO  ;  pure  lime,  200  ;  carbonic  acid  and  loss.  16,5 — 100.0.  » 


OF  BONES  AND  TEETH,  kc. 

Berzelius  is  of  opinion  that  none  of  those  bodie^  existed  in  the  collouring  matter  ;  but. 
merely  their  basis,  iron,  phosphorus,  calcium,  &c.,  And  that  they  aie  formed  during  the 
incineration. 

"  The  albumen  of  blood  leaves  the  same  quantity  of  ashes  as  the  colouring  matter.  But 
these  ashes  contain  no  traces  of  iron." 

"  Dr.  Gordon  has  rendered  it  probable,  that  during  the  coagulation  of  blood  a  little  heat 
is  evolved."  (Annals  of  Philosophy,  iv.  139.) 

Rouelle  has  obtained  nearly  the  same  ingredients,  only  in  different  proportions,  from  the 
blood  of  a  great  variety  of  animals. 

F&tal  blood.  "  Fourcroy  made  some  experiments  on  the  blood  of  the  foetus.  He  found 
that  it  differed  from  the  blood  of  the  adult  in  three  things.  1st,  Its  colouring  matter  is 
darker,  and  seems  to  be  more  abundant.  2d,  It  contains  no  fibrine,  but  probably  a  greater 
proportion  of  gelatin  (?)  than  blood  of  adults.  3d,  It  contains  no  phosphoric  acid. — Four. 
Jinn,  de  Chim.  vii.  p.  162. 

Diseased  blood.  1st.  "  Deyeux  and,>  Parmentier  (Journ.  de  Phys.  xliv.  454,)  ascertained 
thtit  the  buffy  coat  consists  of  the  fibrine.  The  cruor,  deprived  of  this  substance,  is  much 
.sotteetbari  usual,  and  almost  totally  soluble  in  water. 

2.  "  The  blood  drawn  from  several  patients  labouring  under  sea  scurvy,  affording  scarce- 
ly any  remarkable  properties  to  these  chemists,  except  a  peculiar  smell,  and  an  albumen 
which  was  not  so  easily  coagulated  as  usual." 

3.  The  blood  of  patients  in  putrid  fevers  gave  no  sensible  alteration  in  its  properties  to 
the  examinations  of  these  chemists. 

4.  "  The  blood  of  diabetic  patients;  the  serum  of  the  blood,  according  to  the  experiments 
of  Dobson  and  Hollo,  assumes  the  appearance  of  whey.     Dr.  Wollaston  has  shown,  that  it 
contains  no  perceptible  quantity  of  sugar,  even  when  the  urine  is  loaded  with  it." 

MILK  separates  into  cream,  "curd  and  whey.  1st,  Cream  is  composed  of  a  peculiar  oil, 
curd,  and  serum.  Cream  of  the  specific  gravity  of  1.0244,  was  analysed  by  Berzelius,  who 
found  it  composed  of — butter,  4.5;  cheese,  3.5  ;  whey,  92.0. — 100.0. 

2d,  Curd  may  be  precipitated  by  rennet,  or  the  acids,  alkalies  dissolve  it  easily.  The 
constituents  of  curd,  according  to  the  analysis  of  Gay  Lusac  and  Theuard,  are  as  follows: — 

Carbon 59.781 

Oxygen 11.409 

Hydrogen 7.429 

Azote 21,381—100.000 

Dr.  Thomson's  application  of  this  analysis  to  the  atomic  theory. 
7  atoms  Carbon  5.25      .60.87  C      By  doubling  the  number  J  14  atoms  Carbon 

1  atom  Oxygen  1.00       11.60  j  of  atoms,  it  may  be  com-  f     5 Oxygen 

5 Hydro'   0.625      7.24  ")  pared  with  gelatin,   albu-  ("10 Hydrog. 

1 Azote     1.75      20.29  f  men,  and  fibrine.  3     2 Azote 


8.625  100.00  28  17.25 

Proust  has  found  in  cheese  an  acid,  which  he  calls  the  cascic  acid,  to  which  he  ascribes 
several  of  the  peculiar  properties  of  cheese.  (Journ.  de  Phys.  Ixiv.  107.) 

The  coagulation  of  curd  probably  depends  upon  the  same  cause  as  that  of  albumen. 

3.  Whey  still  possesses  some  curd  ;  on  evaporation  it  deposits  crystals  of  sugar  of  milk. 
Towards  the  end  of  the  evaporation,  some  crystals  of  muriate  of  potash,  and  of  /nuriate  of 
soda,  make  their  appearance.  (Parmentier  Journ.  de  Phys.  xxxviii.  417.)  According  to 
Scheele,  it  contains  also  a  little  phosphat  of  lime.  (Scheele,  ii.  61.)  Fourcroy  and  Vau- 
quelin,  Thenard,  Bouillon,  la  Grange,  and  Berzelius,  have  analyzed  whey.  The  latter 
chemist  gives  the  following  as  the  ingredients  of  milk  deprived  of  its  cream: — 

Water 928.75 

Curd  with  a  little  cream     ....      28.00 

Sugar  of  milk 85.00         * 

Muriate  of  potash 1.70 

Phosphate  of  potash 0.25      Milk  may  be  made  to  ailbrd  a  liquor  re- 
Lactic  acid,  acetate  of  potash,  with  )        g  0~  sembling  wine  or  beer,  from  which  alcohol 

a  trace  of  lactate  of  iron  )  mav  be  separated  by  distillation.  The  Tar- 
Earthy  phosphates -  0.30  tars  obtained  all  their  spirituous  liquors  from 

mare's  milk. 

1000.00 

It  has  been  ascertained,  that  milk  is  incapable  of  being  converted  into  wine,  till  it  has 
become  sour;  after  this,  nothing  is  necessary  but  to  place  it  in  the  proper  temperature;  the 
fermentatioft  begins  of  its  own  accord,  and  continues  till  the  formation  of  wine  be  comple- 
ted. (Parmentier,  Journ.  de  Phys.  38.  365.)  A  great  quantity  of  carbonic  acid  is  extrica- 
ted during  the  fermentation  of  milk.  (Scheele,  ii.  66.)  Milk  is  fermented  and  kept  for 
many  months,  or  even  years,  in  the  Orkney  and  Shetland  Islands;  but,  along  with  a  small 
portion  of  alcohol  which  i*  formed,  the  acidity  is  inconsiderable. 


100  APPENDIX. 

'The  ingredients  of  the  milk  of  most  animals  are  nearly  the  same,  the  proportion  only 
differs. 

The  human  milk  differs  from  cow's  milk  1st,  in  containing  a  much  smaller  quantity  of 
curd.  2d,  Its  oil  is  so  intimately  combined  with  its  curd,  that  it  does  not  yield  butter.  3d, 
It  contains  rather  more  sugar  of  milk. 

Parmentier  and  Deyeux  ascertained,  that  the  quantity  of  curd  in  woman's  milk  increases 
in  proportion  to  the  time  after  delivery.  (Journ.  de  Phys.  38.  422.) 

None  of  the  methods  by  which  cow's  milk  is  coagulated,  succeed  in  producing  the  coa- 
gulation of  the  human  milk.  (Clarke  Irish  Trans,  vol.  ii.  p.  175.) 

BiirE  (human.)  The  following  is  the  analysis  of  bile,  according  to  Berzelius: — water, 
908.4;  picromel,  80.0;  albumen,  3.0;  soda,  4.1;  phosphate  of  lime,  0.1;  common  salt,  3.4; 
phosphate  of  soda,  with  some  lime,  1.0. — 1000. 

Biliary  calculi  are  formed  either  entirely  of  cholesterine;  or  they  also  contain  a  yellow 
concrete  mucous,  picromel,  and  rarely  phosphate  of  lime  or  carbonate  of  lime.  These  lat- 
ter ingredients  frequently  almost  entirely  replace  the  cholesterine.  (  Gren.  Orfila  ) 

CERUMEN  OF  TH  •  EAR.  Vauquelin  considers  it  composed  of  the  following  substances. 
1st,  Albumen.  2d,  An  inspissated  oil.  3d,  A  colouring  matter.  4th,  Soda.  5th,  Phos- 
phate of  lime.  (Fourcroy,  ix.  373.) 

TEARS.  According  to  the  analysis  of  Fourcroy  and  Vauquelin  (Jourh.  de  Phys.  vol. 
xxxix.  p.  236,)  they  are  composed  of  the  following  ingredients: — 1st,  Water.  2d,  Mucus. 
3d,  Muriate  of  soda.  4th,  Soda.  5th,  Phosphate  of  lime.  6th,  Phosphate  of  soda. 

"  The  saline  parts  amount  only  to  about  0.01  of  the  whole.  The  mucus  contained  in  the 
tears  has  the  property  of  absorbing  oxygen  gradually  from  the  atmosphere,  and  of  becoming 
thick  and  viscid,  and  of  a  yellow  colour.  This  property  of  acquiring  new  qualities  from 
the  absorption  of  oxygen,  explains  the  changes  which  take  place  in  tears  in  some  diseases 
of  the  eye." 

SWEAT  contains  salivary  mucus;  osmazome;  lactic  acid;  lactate  of  soda;  and  hydro- 
chlorate  of  potass  and  soda.  (Berzelius.) 

Thenard  found  it  composed  of  an  animal  substance  analagous  to  gelatine  ;  acetic  acid  ; 
hydrochlorate  of  soda;  phosphate  of  lime;  phosphate  of  iron,  and  water. 

URINE.  The  human  urine,  in  a  state  of  health,  has  a  specific  gravity  of  1.02.  It  con- 
tains urea,  3.01;  a  matter  analagous  to  saliva,  osmazome,  lactic  acid,  lactate  of  ammonia, 
and  a  little  urea,  1.724;  mucus,  0.032;  uric  acid,  0.10;  phosphate  of  ammonia,  0.150;  sul- 
phate of  potassa,  0.371;  sulphate  of  soda,  0.316;  hydrochlorate  of  soda,  0.445;  phosphate  of 
soda,  0.294;  phosphate  of  lime,  with  a  little  phosphate  of  magnesia,  and  a  trace  of  the  fluate 
of  calcium,  0.1 ;  silica,  0.003;  water,  93.3.  (Berzelius.) 

Besides  the  constituents  of  healthy  urine,  as  determined  by  Berzelius,  the  following  have 
been  occasionally  detected  in  it;  albumen;  resin  with  ulmine;  acetic  acid;  benzoic  acid  (in 
infants;)  carbonic  acid;  sulphur;  chloruret  of  potassium;  and  iron. 

Urine  which  is  excreted  in  the  morning,  generally  contains  more  of  the  saline  and  solid 
ingredients.  Uric  acid  abounds  most  in  the  urine  of  individuals  who  live  on  animal  diet. 
Urine  absorbs  oxygen  from  the  atmosphere,  and  passes  into  a  state  of  putrid  fermentation. 
This  is  more  or  less  rapid  according  to  the  elevation  of  the  temperature;  and  the  quantity 
of  mucus  and  albumen  present  in  the  urine  is  considerable. 

The  urine  in  diabetes  niellitus  has  a  specific  gravity  of  from  1.026  to  1.05.  It  generally 
contains  no  urea — sometimes  a  minute  quantity  of  it.  It  is  remarkable  for  its  quantity,  and 
for  the  saccharine  matter  which  it  holds  in  solution;  the  saline  ingredients  are  generally  pre* 
sent,  but  in  smaller  proportions.  As  the  quantity  of  sugar  diminishes,  that  of  albumen  in- 
creases, and  this  latter  is  replaced,  as  the  disease  disappears,  by  urea  and  uric  acid.  The 
chief  difference  between  this  urine  and  that  secreted  in  diabetes  insipidus,  consists  in  the 
absence  of  saccharine  matter  from  the  latter. 

Icteric  urine  is  frequently  yellow  and  bitter,  and  contains  the  principles  of  bile. 
In  acute  dropsy  the  urine  is  generally  charged  with  albumen.    When  dropsy  results  from 
disease  of  the  liver,  the  urine  is  brown,  and  deposits  a  brown  sediment. 
•    SEMEN,  when  ejected,  is  the  product  of  two  different  glands,  the  one  fluid  and  milky, 
supposed  to  be  secreted  by  the  prostate  gland;  the  other  a  thick  mucilaginous  substance, 
considered  to  be  secreted  by  the  testes,  and  in  which  numerous  white  shining  filaments  may 
be  discovered:  it  has  a  slightly  disagreeable  odour,  an  acrid  irritating  taste,  and  is  of  a  great- 
er specific  gravity  than  water.     As  this  liquid  cools,  the  mucilaginous  parts  become  trans- 
parent, and  acquire  a  greater  consistency,  but  in  about,  twenty  minutes  after  its  emission, 
the  whole  becomes  perfectly  liquid. 

This  change  supervenes  without  any  absorption  of  moisture  from  the  air,  and  without  its 
action,  taking  place  equally  in  close  vessels.  Semen  is  insoluble  in  water  before  this  spon- 
taneous liquefaction,  but  readily  so  afterwards.  (Vauquelin,  Jinn,  de  Chim.  ix.  70.)  When 
semen  is  kept  in  a  moist  air,  at  about  77°,  it  acquires  a  yellow  colour,  like  the  yolk  of  an 
egg;  it  exhales  the  odour  of  putrid  fish,  and  its  surface  is  covered  by  the  byssus  septica. 


OF  BONKS  AND  TEETH,  &c. 

According  to  Vauquelin  semen  is  composed  of  water,  90;  mucilage,  6;  phosphate  of  lime, 

3;  soda,  l.=  100. 

The  OVA.  from  the  ovaria  of  the  human  subject :  gelatine,  albumen,  phosphate,  with  an 

alkaline  base  in  excess.     (John's  Chemical  Writings,  vi.  158.) 

AMNJOTIC  FLUID,  which  surrounds  the  foetus,  in  the  human  species  is  of  a  slightly  milky 
lour,  owing  to  a  curdy  matter  suspended  in  it,  of  a  weak  pleasant  odour,  and  saltish 
<te;  specific  gravity  1.005;  is  composed  of  about  water,  98.8;  albumen,  muriate  of  soda, 


colour 
tast 


<oda,  phosphate  of  lime,  lime,  1.2  =  100.0.  (Vauquelin  and  Buniva,  Jinn,  de  Chim. 
xxxiii.  270.  274.)  A  curdy-like  matter  is  deposited  on  the  surface  of  the  foetus,  evidently 
from  the  liquor  of  the  amnios.  Vauquelin  and  Buniva  have  shown  that  it  is  different  from 
any  thing  contained  in  this  fluid  ;  that  it  has  in  its  chemical  relations  a  great  resemblance 
to  fat.  They  conjecture  that  it  is  formed  from  the  albumen  of  this  liquid,  which  has  un- 
dergone some  unknown  changes.  It  appears  to  be  of  service  in  preserving  the  skin  of 
the  foetus  from  being  acted  of  by  the  liquor  of  the  amnios,  and  to  facilitate  its  passage  hi 
parturition. 

Pus.  Its  taste  is  insipid,  and  it  has  no  smell  when  cold.  Before  the  microscope  it  exhi- 
bits the  appearance  of  white  globules  swimming  in  a  transparent  fluid,  specific  gravity 
from  1.031  to  1.033.  When  incinerated,  the  ashes  give  traces  of  iron.  (Gren's  Hand- 
buck,  ii.  426.)  It  produces  no  change  on  vegetable  blues.  Alcohol  thickens  pus,  but  does 
not  dissolve  it ;  nor  does  it  unite  with  oils.  Soluble  in  sulphuric  acid,  but  separated  on  the 
addition  of  water.  The  same  is  the  case  with  nitric  acid.  Muriatic  acid  also  dissolves  it 
when  heated,  and  it  is  again  separated  by  water. 

The  fixed  alkaline  leys  form  with  it  a  whitish  ropy  fluid,  which  is  decomposed  by  water, 
the  pus  being  precipitated.  Corrosive  sublimate,  nitrate  of  mercury,  and  nitrate  of  silver, 
give  a  whitish  precipitate  from  its  solution,  indicating  an  analogy  with  albumen. 

Expectorated  matter  yields  traces  of  sulphur,  and  perhaps  also  of  phosphorus;  and  it  con- 
tains the  following  saline  substances: — 1st,  Muriate  of  soda,  varying  from  H  to  2^  in  the 
1000  of  expectorated  matter  2d,  Phosphate  of  lime,  half  a  part  in  the  1000.  3d,  Ammo- 
nia united  probably  to  phosphoric  acid.  4th,  A  phosphate  probably  of  magnesia.  5th,  Car- 
bonate of  lime.  6th,  A  sulphate.  7th,  Vitrifiable  matter,  probably  silica.  8th,  Oxide  of 
iron.  The  whole  of  these  last  six  substances  scarcely  amount  to  one  part  in  the  1000  of 
expectorated  matter. 

The  proportion  of  saline  matter  of  albumen  present  in  expectorated  matter  varies  much, 
in  different  circumstances.  The  thicker  it  is,  in  general  the  smaller  is  the  quantity  of  the 
«aHne  matter:  whereas,  when  very  thin,  it  is  often  impregnated  with  salts,  especially  with 
the  muriate  of  soda  to  a  great  degree,  and  tastes  distinctly  salt  and  hot. 

Liquor  of  the  pericardium.  Dr.  Bostock  (Nicholson's  Journ.  xiv.  147.)  considers  it  to 
be  composed  of — water,  92.0;  albumen,  5.5;  mucus,  2.0;  muriate  of  soda,  0.5 — 100.0. 

Liquor  of  dropsy.  Dr.  Bostock  found  the  liquid  formed  in  "  spina  bifida"  to  be  com- 
posed as  follows: — water,  97.8;  muriate  of  soda,  1.0;  albumen,  0.5;  mucus,  0.5.  gelatin, 
0  2;  lime,  a  trace.  (Nichol.  Journ.  xiv.  145.) 

The  same  kind  of  fluid  obtained  from  the  head  of  a  child  of  ten  years  was  examined  by 
Dr.  Prout.  It  faintly  reddened  litmus  paper.  Its  constituents  were  as  follow: — water,  987. 
18;  albumen,  precipitated  by  nitric  acid  and  heat,  1.66;  substances  soluble  in  alcohol  (fatty 
adipocirous  matter,  lactate  of  soda,)  1.65;  substances  soluble  in  water — 9.51.  viz.  muriates 
of  potash  and  soda,  6.80;  sulphate  of  soda  and  some  animal  matter  not  coagulated  by 
heat,  2.71— 1000.00.  (Ann.  of  Phil.  xvi.  151.) 

Liquor  of  blisters.  The  analysis  of  Macqueron  (Ann.  de  Chim.  xiv.  225.)  gives  it  nearly 
the  same  constituents  as  the  serum  of  the  blood :  from  200  parts  he  obtained — albumen, 
36  -,  muriate  of  soda,  4;  carbonate  of  soda,  2;  phosphate  of  lime,  2;  water,  156 — 200. 

HUMAN  FJECES.  Their  colour  seems  to  depend  upon  the  bile  mixed  with  the  food  in  the 
digestive  canal;  when  too  light  it  is  supposed  to  denote  a  deficiency  of  bile;  when  too  dark, 
there  is  supposed  to  be  a  redundancy  of  that  secretion.  The  following  table  shows  the  an- 
alysis of  BERZELIUS.  (Gehlin's  Journ.  vi.  536.) 

Water 73.3' 

Vegetable  and  animal  remains    -        -       7.0 

Bile 0.9 

Albumen 0.9 

Peculiar  and  extractive  matter  sup-  ^ 

posed  to  be  formed  from  picro->       2.7 
mel.  \ 

Salts*  2.3 

Slimy  matter,  consisting  of  picromel, 

peculiar  animal  matter,  and  inso- J     14.0 
luble  residue. 


100.0 


*  The  SALTS,  their  relative  proportions. 
Carbonate  of  soda     -        -        -        -        35 
Muriate  of  soda         ....          4 
Sulphate  of  soda        -  2 

Amm.  phosphate  of  magnesia,  -  2 

Phosphate  of  lime.    .        -        -  4 


102 


APPENDIX. 


GASES  EXISTING  IN  THE  IXTESTIVAL  c  AX  A.L.  These  may  be  ascribed  to  three  sources: 
—1st,  from  the  common  air  swallowed  with  the  food  ;  2d,  from  the  decomposition  of  the 
intestinal  contents;  and  3d,  from  the  occasional  secretion  of  gas  from  the  mucus  surface  of 
the  tube. 

The  gases  from  the  first  source  are  found  chiefly  in' the  superior  portions  of  the  canal; 
those  from  the  second  source  in  the  lower  part,  and  those  from  the  third,  are  by  no  means 
limited  in  their  situation.  It  is  reasonable  to  suppose  that  a  large  proportion  of  the  azote 
and  carbonic  acid  is  derived  from  this  last  source. 

From  the  experiment  of  Magendie  and  Chevrule,  who  examined  very  soon  after  death 
the  gaseous  contents  of  the  stomach  and  intestines  of  four  criminals  executed  at  Paris,  the 
following  appear  to  be  the  proportions  and  the  relative  quantities  in  the  different  portions 
of  the  canal. 


1.  Gases  in  the  Stomach. 
Oxygen*    .... 
Carbonic  acid     - 
Hydrogen  ... 

Azote        - 


11.00 

14.00 

3.55 

71.45 


100.00 


2.  Ga$£s  in  the  small  Intestines.^ 
Oxygen        w  00.00    -    -    00.00    -    -  00.0 
Carbonic  acid  24.39     -    -    40.00    -    -  25.0 
Hydrogen        55.53     -    -     51.15     -     -    8.4 
Azote  20,08     -    -      8.85    -    -  66.6 


100.00 


100.00 


100.0 


3.  Gases  in  the  large  Intestines. 

Carbonic  acid      -        -        -        -        -        43.50      - 

Hydrogen  and  carburetted  hydrogen  54.7 

Azote 

4.  Gases  in  the  Caecum. 
Carbonic  acid    -        -        -        ...    12.5 
Hydrogen    -               -        -    -   -          7.5 
Carburetted  hydrogen          -        -         12.5 
Azote 67.5 


100.0 


70.0 
11.6 

51.03=100.00   18.4=100.0 

5.  Gases  in  the  Rectum. 
Carbonic  acid       - 
Carburetted  hydrogen  • 
Azote     --- 


(4>m.  de  Chim.  et  Phys.  ii.  492.) 


42.86 
11.18 
45.96 

V 

100.00 


*  The  oxygen  seems  to  be  absorbed  by  the  blood  before  it  reaches  the  small  iniestiiies- 
t  Results  in  the  different  individuals. 


FINIS. 


ANALYTICAL   INDEX. 


PREFACE.— Preliminary  discourse.  Physiology—the  Science  of  Life, 
Definition  of  Life,  2,  3. 

§  I.  Of  Natural  Beings,  9. 

They  are  inorganic  or  organized. — The  former  are  simple  or  complex; 
the  latter  always  complex,  and  distinguished  into  vegetable  and  animal* 
Reciprocal  dependence  of  all  these  berhgs,  9. 

§11.   Of  the  Elements  of  Bodies,  9. 

The  Elements  of  Bodies.  Their  number  forty-four  5  but  it  is  probable 
that  several  appear  to  us  simple,  from  the  imperfection  of  our  means  of 
analysis,  10. 

§  III.  Differences  between  Organized  and  Inorganized  Bodies,   1 1. 

i 

Differences  between  organized  and  inorganized  bodies,  11.  Homoge- 
neousness  of  the  latter ;  complex  nature  of  the  former  ;  necessary  co-ex- 
istence of  fluids  and  solids  in  all  organized  and  living  beings,  simplicity 
of  inanimate  matter  :  complex  nature  and  tendency  to  decomposition  of 
organized  bodies,  12,  13,  14. 

§  IV.  Differences  Between  Vegetables  and  Animals,    14. 

Differences  between  animals  and  plants,  14.  The  great  distance  be- 
tween the  mineral  and  vegetable  kingdom.  A  considerable  approxi- 
mation, on  the  contrary,  between  animals  and  plants,  15.  Of  all  the 
characters  which  mark  the  differences  between  these  substances,  the 
most  remarkable  is  the  presence  of  an  alimentary  tube,  which  is  found  in 
every  animal  from  man  down  to  the  polypus,  15.  In  all  animals,  nutri- 
tion is  performed  by  two  surfaces,  especially  by  the  internal ;  the  alimen- 
tary canal  is  the  most  essential  part  of  their  body,  16.  It  retains  life 
longer  than  any  other  part— Experiments  disproving  Haller's  opinion  on 
this  subject,  16. 

§V.    Of  Life,   16. 

Consists  of  a  number  of  phenomena  proportioned  to  the  complication 
of  the  organization,  17,  Simple  in  plants,  in  xvhich  its  actions  are  limit- 


104 

ed  to  nutrition  and  reproduction,  17.  Of  Life  in  the  polypus;  this  ani- 
mal, consisting  merely  of  a  sentient  and  contractile  pulp,  shaped  iiito  an 
alimentary  cavity,  18.  Of  life  in  worms,  18— in  crustaceous  animals,  its 
apparatus  more  perfect,  19.  Of  life  in  cold-blooded  animals,  19.  In 
warm-blooded  animals  and  in  man,  20.  General  view  of  the  human  or- 
ganization, 20,  21.  Of  the  elementary  fibre,  23.  Dependence  of  life 
on  the  oxydation  of  the  blood  in  the  lungs,  and  on  the  distribution  of 
this  vivified  blood  throughout  the  organs,  23. 

§  VI.    Of  tils  Vital  Pro/icrfiee  ;   Sensibility  and  Contractility,  23. 

These  two  properties  not  possessed,  in  an  equal  degree,  by  all  living 
bodies,  23.  Modifications  of  sensibility  in  different  organs,  27.  Obser- 
vations on  the  contractility  of  serous  membranes,  27.  Caloricity,  29. 
Laws  of  sensibility,  30.  Influence  of  sieep,  of  climates,  of  the  seasons,, 
of  the  age,  &c.  on  the  vital  properties,  32,  33,  34. 

*  §  VII.    Of  Sympathies,  34. 

Of  sympathy,  34.  Diseases  arising  from  association  ;  Synergies,  355 
36,  37. 

§  VIII.    Of  Habit,  33. 

Of  habit,  38.  It  uniformly  Jessens  physical  sensibility — A  curious 
fact  showing  the  effects  of  habit,  39.  Habit  impairs  the  sensitive  power 
but  improves  the  judgment,  41. 

§  IX.     Of  the  Vital  Principle,  42. 

• 

The  vital  principle,  not  a  being  existing  by  itself,  and  independently 
of  the  actions  by  which  it  manifests  itself,  42.  'A  perpetual  struggle  in 
organized  bodies,  between  the  laws  of  the  vital  principle  and  those  of 
universal  nature,  43.  The  vital  principle  resists  the  laws  of  chemistry, 
of  physics  and  mechanics,  43.  There  takes  place,  however,  in  the  ani- 
mal economy,  chemical,  physical  and  mechanical  phenomena,  but  they 
are  always  modified  by  the  vital  principle,  44.  Influence  of  the  stature 
on  the  energy  of  the  vital  powers  and  even  on  longevity,  44.  Vis  Medi- 
catrix  naturae,  44.  Theory  of  inflammation,  46.  Analogy  between  the 
turgescence  of  an  inflamed  part,  and  of  one  in  a  state  of  erection,  as  the 
penis,  %c.  48.  Indirectly  tonic  influence  of  cold,  49. 

§  X.       Of  the  System  of  the  Great  Sympathetic  Nerve.  9. 

These  nerves  are  to  be  considered  as  connecting  the  organs  of  the 
functions  of  assimilation,  as  the  cerebral  nerves  unite  those  of  the  exter- 
nal functions,  49.  They  are  the  only  nerves  found  in  several  animals 
without  vertebra.  They  arise  from  all  the  vertebral  nerves,  from  which 
they  receive  filaments,  as  well  as  from  the  sixth  cerebral  pairs,  50.  Gan- 
glions of  the  sympathetic  nerves;  the  semi-lunar  ganglion,  the  principal, 
50.  The  great  sympathetics  render  the  internal  organs  independent  of 
the  will,  51. 


INDEX.  105 


§  XI.     Of  the  relations  to  Physiology  to  several  other  Sciences,  54, 

The  relation  of  physiology  to  physics',  chemistry,  and  mechanics,  54. 
Connexion  of  physiology  with  human  and  comparative  anatomy,  56.  Its 
connexion  with  medicine,  59. 

§  XII.      Classification  of  the  Vital  Functions,  60. 

The  best  divisions  of  the  vital  functions  is  that  which  was  first  pointed 
out  by  Aristotle,  adopted  by  Buffon,  and  completely  developed  by  Gri- 
inaud,  60.  Modifications  of  which  this  division  is  susceptible  ;  preser- 
vative functions  of  the  individual  or  of  the  species,  61.  These  two  great 
divisions  further  divided  into  two  orders,  61.  Why  man  is  subject  to 
more  diseases  than  animals,  63,  64. 

Of  the  arrangement  of  this  work,  66.  The  voice  is  a  natural  connex- 
ion between  the  preservative  functions  of  the  individual  and  those  of  the 
species,  67.  The  history  of  the  ages  and  temperaments,  and  of  the 
varieties  of  the  human  species  5  the  account  of  death  and  putrefaction 
forms  a  separate  appendix,  67. 


FIRST    CLASS. 

Functions  subservient  to  the  preservation  of  the  Individual, 
ORDER  FIRST. 

Functions  of  Assimilation. 
CHAPTER  I. 
On  Digestion,  71. 

Definition  of  this  function,  71.  General  considerations  on  the  digestive 
apparatus,  72.  Connexion  between  the  nature  of  the  aliment  and  the  ex- 
tent of  the  digestive  tube,  72.  Of  aliments,  73.  The  nutrient  principle  ob- 
tained from  the  aliment,  by  our  organs,  is  always  the  same,  73.  Of  the 
nature  of  the  alimentary  principle,  74.  Differences  of  Regimen,  ac- 
cording to  the  climate,  75.  Hunger  and  thirst,  76.  Mastication,  79. 
Action  of  the  lips,  of  the  cheeks,  of  the  tongue,  of  the  teeth,  of  the  jaws, 
78,  79,  80.  The  salivary  solution,  81,  82.  Deglutition,  its  mechanism, 
83,  84.  Deglutition  of  fluids  and  of  gaseous  substances,  85.  Of  the  ab- 
domen, 86.  Of  digestion  in  the  stomach,  87.  Different  systems  of  di- 
gestion ;  of  concoction,  fermentation,  88.  Of  putrefaction,  89.  Of  tri- 
turation;  of  digestion  in  granivorous  fowls,  90.  Of  maceration,  91. 
Phenomena  of  rumination,  91.  Of  the  gastric  juice,  92,  Its  source,  its 

O 


106  INDEX. 

quantity,  and  solvent  qualities,  94.  Digestion  chiefly  consists  in  the  so- 
lution of  the  aliment  in  this  fluid,  95.  Singular  cases  of  a  fistula  of  the 
stomach,  97.  Action  of  the  stomach,  97.  Functions  of  the  pylorus,  100. 
Of  vomiting,  101.  Digestion  in  the  duodenum,  102.  Of  the  bile  and  its 
secretory  organs,  103.  Circulation  of  the  blood  in  the  liver,  104.  Uses 
of  the  spleen,  105.  Of  the  pancreas  and  pancreatic  juice,  107.  Separa- 
tion of  the  alimentary  matter  in  two  substances,  the  one  chylous  the  other 
excrementitions,  108.  Of  the  action  in  the  small  intestines,  108.  The 
uses  of  their  curvatures  and  valvulae  conniventes  ;  of  the  peristaltic 
motion,  109.  Of  digestion  in  the  great  intestines,  110.  Uses  of  the  ap- 
pendicula  vermiformis  of  the  ccecum.  Of  the  evacuation  of  the  faeces, 
111.  Intestinal  gases,  112. 

Of  the  secretion  and  excursion  of  the  urine,  113.  Of  the  caliber  of 
the  renal  arteries,  structure  of  the  kidneys,  114.  Action  of  the  kidneys 
and  ureters,  115.  Accumulation  of  the  urine  within  the  bladder,  117. 
In  what  manner  itis  expelled,  1 18.  Physical  qualities  of  the  urine,  119. 
Chemical  analyses  of  this  fluid,  urea,  120.  Its  retention  produces  urir 
nous  fever,  121.  Experiments  on  the  effects  attending  retention  of  urine 
by  tying  the  ureters,  in  living  animals,  122.  Urinary  calculi,  why  most 
frequent  in  cold  and  damp  climates,  124—125. 


CHAPTER  II. 

Of  Msorfition,  125. 

Absorption  takes  place,  in  every  part  of  the  body,  both  on  its  surface 
and  in  its  internal  parts,  125.  Absorption  more  or  less  active  in  differ- 
ent circumstances,  125.  Its  activity  is  very  slight  on  the  external  sur- 
face, except  where  the  skin  is  thin  and  epidermis  moist,  126. 

Absorbing  mouths,  130.  Their  mode  of  action,  in  absorption,  130. 
Of  the  lymphatics,  131.  Their  innumerable  anastomoses,  from  the 
union  of  which  there  is  formed  a  mesh-work  enveloping  the  whole  body, 
132.  Pathological  inferences,  133. 

Of  the  conglobate  glands,  134.  Their  action,  104.  Circulation  of 
the  lymph,  134.  Observations  on  cancer,  135. 

Of  the  thoracic  duct,  136.  Of  the  physical  and  chemical  properties 
of  the  lymph,  137. 

CHAPTER  III. 
Of  the  Circulation,  139. 

Definition  and  general  idea  of  this  function,  139.  Of  the  action  of 
the  heart  ;  uses  of  the  pericardium,  140.  Connexion  between  the  bulk 
of  the  heart,  and  strength  and  courage,  140.  Singular  case  of  commu- 
nication between  the  two  ventricles,  141.  Structure  of  the  heart,  142. 
Action  of  the  heart,  in  circulation,  144.  Shortening  and  pulsation  of 
the  heart,  every  time  the  ventricles  contract,  145 — 146.  The  quantity 
of  blood  which  these  cavities  send  out,  along  the  arteries,  147. 

Action  of  the  arteries,  147;  their  arrangement  and  anastomoses,  148, 
Of  the  structure  of  the  arteries,  the  force  and  contractility  of  their  dif- 
ferent coats,  149.     Dilatation  of  the  arteries,  149.    Of  the  pulse  and.  it* 
"ties.  154.    Velocity  of  the  circulation  aJong  the  arteries.  \*~. 


INDEX.  107 

Of  the  capillary  vessels,  155.  Those  which  convey  a  colourless  fluid, 
136.  Of  the  manner  in  \vhich  the  blood  flows  along  these  vessels,  157. 
Terminations  of  the  arterial  systems,  159. 

Of  the  action  of  the  veins,  160.  Proportion  of  the  arterial  to  the^ve- 
nous  blood  5  difference  of  arrangement  and  structure  between  the  ar- 
teries and  veins,  160.  Of  the  use  of  the  valves  of  the  veins,  161.  Gra- 
dual increase  of  velocity  in  the  venous  circulation.  Of  the  use  of  the 
vena  azygos,  162.  Reflux  of  the  blood  in  the  great  venous  trunks,  163. 
Theory  of  the  circulation,  164.  Partial  circulations  in  the  midst  of  the 
general  circulation,  165.  Of  the  two  divisions,  venous  and  arterial,  of 
the  circle  of  circulation,  166.  Organs  situated  on  the  two  points  of  in- 
tersection of  this  great  circle,  166. 

CHAPTER  IV. 

Of  Respiration,  167. 

Of  all  the  changes,  which  the  blood  undergoes,  in  penetrating  through 
the  organs  placed  in  the  course  of  the  circulation,  the  most  remarkable 
are  those  it  receives  from  respiration,  167.  Differences  of  arterial  and 
venous  blood,  167.  Of  the  atmosphere,  167.  Action  by  which  respi- 
ration is  performed,  170.  Motions  of  the  ribs,  171.  Difficult  respiration, 
172.  Structure  of  the  lungs,  173.  Use  of  the  bronchial  arteries,  173. 
Pulmonary  inflammations,  176.  Changes  on  the  air  and  on  the  blood  by 
respiration,  177.  Vitality  of  the  lungs,  178.  Respiration  of  certain 
animals,  179.  Division  or  ligature  of  the  eighth  pair  of  nerves,  182. 

Of  animal  heat,  183.  Animal  heat  is  independent  of  the  media  in 
•which  animated  beings  live,  183.  The  heat  of  the  animal  body  ninety- 
eight  degrees,  184.  The  lungs  not  the  only  parts  in  which  caloric  is 
disengaged,  184.  Caloric  evolved,  to  a  certain  degree,  in  all  organs  re- 
ceiving arterial  blood,  184.  Cutaneous  evaporation,  the  most  powerful 
means  of  lowering  the  temperature,  186.  It  does  not  explain,  however, 
•why  the  animal  temperature  remains  the  same,  in  a  medium  hotter  than 
the  body;  case  of  a  man  said  to  be  incombustible,  186.  Effects  of  cold, 
188. 

Phenonenon  of  the  circulation  of  the  blood  through  the  lungs,  189. 
Pulmonary  exhalation,  190.  Of  asphyxia,  from  drowning  and  from 
strangulation,  191.  From  noxious  gases  and  from  intoxication,  193. 
From  obstruction  of  the  glottis;  of  the  asphyxia  of  new  born  children, 
194. 

Of  several  phenomena  of  respiration,  as  sighing,  yawning,  sneezing, 
coughing,  hiccup,  and  laughter,  195.  Cutaneous  perspiration,  196. 
Its  connexion  with  the  other  functions,  196.  Its  quantity,  198.  Of  the 
sweat ;  of  the  formation  of  carbonic  acid  gas  on  the  surface  of  the  skin, 
200.  Of  the  uses  of  the  cutaneous  perspiration,  200. 

CHAPTER  V. 

Of  the  Secretions,  20 1. 

Classification  of  the  animal  fluids,  201.  Chemical  classification  of  the 
fluids  by  Fourcroy,  the  best,  202.  Of  the  blood.  Of  its  physical,  che- 
mical, and  vital  properties,  203.  Of  sanguification,  204.  Of  the  ef- 
fects of  regimen  on  the  blood,  205.  The  transfusion  of  blood,  208. 


108  INDEX. 

Of  the  secretory  apparatus,  210.  Serous  transudation,  210.  Secretion 
in  the  mucus  follicles,  212.  In  the  conglomerate  glands,  212.  Of  acci- 
dental secretions,  212.  Influence  of  the  nervous  energy  on  the  secretions, 
214.  Influence  of  the  imagination  on  the  secretions,  217.  Quantity  of 
of  fluids  secreted,  218. 

Secretion  of  adeps  within  the  cellular  tissue,  219.  Difference  of  quan- 
tity and  quality  of  this  fluid,  in  the  different  parts  of  the  body,  220.  Of 
the  uses  of  the  adeps,  220.  Circumstances  which  increase  or  lessen  its 
secretion,  221.  Analogy  of  the  marrow  of  the  bones  to  adeps,  22 1.  Of 
the  insensibility  of  the  medullary  membrane,  222. 

CHAPTER  VI. 

Of  Nutrition^  223. 

Nutrition  is  the  completement  of  assimilation,  223.  Period  of  the 
complete  renovation  of  the  body,  223.  Mechanism  of  nutrition ;  from 
arterial  blood  only,  224.  Difference  of  vegetable  and  animal  substances, 
225.  New  products,  225.  Of  the  emunctories,  227.  General  view  of 
the  functions  of  nutrition,  228. 

CHAPTER  VII. 

Of  Sensation,  231. 

Functions  that  are  subservient  to  the  preservation  of  the  individual, 
by  connecting  him  with  surrounding  beings.  Of  sensations,  231.  Na- 
tural succession  to  the  phenomena  of  sense,  231—232. 

Of  light  and  of  colours,  233.  Organ  of  sight — formed  of  three  dis- 
tinct parts,  236.  Use  of  the  eye-lids,  eye-lashes,  and  lachrymal  ducts, 

240.  Eye-ball,  its  structure,  241.  Mechanism  and  phenomena  of  vision, 

241.  Motions  of  the  iris,  242.     Refraction  of  the  rays  of  light  by  the 
membrane,  243,  and  by  the  fluids  of  the  eye  ;  inversion  of  objects  on  the 
retina ;  point  of  distinct  vision,  244.    Defects  of  vision,  245.    Develop- 
ment of  the  eyes  and  their  motions,  246.     Errors  of  vision,  247.     Its  dif- 
ference in  different  animals,  248. 

Organ  of  hearing;  of  sound,  249.  Structure  of  the  ear,  and  mechan- 
ism of  hearing,  249.  Difference  in  animals,  252.  Defects  of  hearing,  252. 

Of  odours,  252.     Organ  of  smell,  253.     Sensation  of  smell,  254. 

Of  taste,  255.  Of  the  tastes  of  different  substances,  organ  of  taste, 
255 — 256.  In  different  animals,  256.  Uses  of  the  nerves  of  the  tongue, 
256.  Galvanic  experiments,  on  this  subject,  257. 

Of  touch,  258.  Its  certainty  and  error,  258.  Of  the  integuments,  258. 
Of  the  nails,  258.  Of  the  hair,  262.  Of  the  hand,  263.  Touch  in  dif- 
ferent animals,  265. 

Of  the  nerves,  267.  Of  their  origin  in  sensible  parts,  267.  Of  their 
structure,  268.  Opinion  of  Reil  on  this  subject,  268.  Of  the  manner  they 
arise  from  each  other,  269.  Of  their  termination  in  the  brain,  269.  Of 
their  comparative  size,  in  different  animals,  and  in  man  at  different 
ages,  270. 

Of  the  coverings  of  the  brain,  272.  Mechanism  of  the  bones  of  the 
skull  and  face,  272.  Use  of  the  sphenoid,  273.  Rounded  form  of  the 
skull,  276.  Uses  of  the  dura  mater,  of  the  arrachnoid,  and  the  pia  mater, 
276.  Size  of  the  brain,  277.  Form  of  the  head,  277.  Connexion  with 


INDEX.  109 

the  intellectual  powers,  278.     Nerves  crossing,  272.     Divergent  and  con- 
vergent fibres,  280.     Cerebral  circulation,  28 1 .     Arterial  blood  retarded, 

281.  Jugular  veins,  282.   Connexion  of  the  action  of  the  brain  and  heart, 

282.  Theory  of  syncope,  284.   Motions  of  the  brain,  286.     Experiments, 
290.     Action  of  the  nerves  and  brain,  293.    Principle  of  motion  and  sen- 
sation, 294.  Different  intellectual  functions  of  different  parts  of  the  brain, 
295.     Not  yet  perfectly  understood,  295. 

Analysis  of  the  understanding,  295.  Perception,  296.  Reasoning  and 
instinct,  297.  Generation  of  the  faculties,  298.  Sensation,  perception, 
attention,  memory,  imagination,  association  of  ideas,  comparisons,  judg- 
ment, reasoning,  299.  Influence  of  signs  on  the  faculties  of  thought,  300. 
Analysis  of  ideas,  by  M.  Destutt  Tracy,  302.  Derangement  of  the  mind, 
302.  Mania,  303.  Idiotcy,  303. 

Of  the  passions,  303-T-304.  State  of  the  intellectual  powers  connected 
with  them,  305.  Effects  on  the  animal  enconomy,  306.  Of  sleep  and 
waking,  307.  Repose  of  the  functions  which  connect  us  with  surround- 
objects  ;  condition  of  the  functions  of  assimilation,  during  sleep,  308. 
Proximate  cause  of  sleep,  310 — 311.  Of  dreams  and  somnambulism, 
313.  Animals  are  also  subject  to  dreams,  313. 

CHAPTER  VIII. 

On  Motions^  3 1 4. 

This  chapter  treats  only  of  voluntary  motions,  whose  organs  may  be 
distinguished  into  active  and  passive  (the  bones  and  muscles,)  3 1 4.  Struc- 
ture and  properties  of  muscular  fibres,  315.  Of  the  tendons  and  aponeu- 
roses,  316.  Phenomena  of  muscular  contraction  determined  by  an  act 
of  the  will,  317.  A  sound  state  of  the  nerves,  arteries,  and  veins  belong- 
ing to  a  muscle  is  necessary  to  its  action,  317.  Theory  of  this  action, 
318.  Preponderance  of  the  flexor  muscles  over  the  extensors,  318. 
The  preponderance  varies,  according  to  the  age,  in  the  state  of  health 
or  disease,  319.  Of  the  power  of  the  muscles  ;  it  bears  a  proportion  to 
the  number  of  their  fibres,  32 1 .  The  degree  of  shortening  of  which  they 
are  capable  is  proportioned  to  the  length  of  their  fibres,  323.  Direction 
of  the  motions  performed  by  the  action  of  the  muscles,  323.  Of  muscu- 
lar flesh,  324.  Galvanism,  326.  Volta's  apparatus,  or  Galvanic  pile,  326. 
Effects  of  Galvanism,  in  the  treatment  of  disease,  330.  General  view  of 
the  osseous  system,  332.  Of  the  vertebral  column  ;  it  forms  the  most  es- 
sential part  of  the  skeleton,  334.  Difference  of  the  stature  at  different 
times  of  the  day,  335.  Of  the  lower  limbs,  335.  Structure  of  the  bones, 
336.  Uses  of  the  periosteum,  and  of  the  marrow,  338.  Theory  of  ne- 
crosis, 339.  Of  the  articulations,  340.  Of  the  articulating  cartilages, 
341.  Of  the  synovia,  341.  Theory  of  anchylosis,  343. 

Of  animal  mechanics  ;  of  standing,  344.  Of  the  centre  of  gravity,  344. 
Tendency  of  the  body  to  fall,  344 — 347.  Standing  is  performed  by  an 
effort  of  the  extensor  muscles,  348.  Reasons  why  it  is  impossible  for  a 
new-born  child  to  stand,  350.  Man  is  the  only  animal  that  can  stand  up- 
right, 350.  Of  falls,  351.  Of  standing  on  one  foot,  352.  A  degree  of 
separation  of  the  feet  necessary  in  standing,  352.  Of  kneeling  5  of  sit- 
ting; of  the  recumbent  posture,  354.  Of  lying  on  the  sides,  354.  Of 
the  prone  and  supine  postures,  355.  The  different  modes  of  recumbent 
posture  have  a  reference  to  the  degrees  of  facility  of  respiration  and  to 


IK)  INDEX. 

the  period  of  life,  336,  Recumbent  posture  on  an  inclined  plane,  neces- 
sary, especially  to  old  people,  357.  Of  motions  of  progression  5  of 
walking,  358.  Of  walking  up  or  down  an  inclined  surface,  360.  Me- 
chanism of  the  articulation  between  the  leg  and  foot,  361.  Of  running, 
362.  Of  leaping,  363.  Leaping-  is  performed  by  the  sudden  extension 
of  the  lower  extremities,  previously  in  a  state  of  flexion,  634 — 365.  Of 
the  vertical  and  oblique  leap,  365.  Of  swimming;  man  swims  with  dif- 
ficulty, 365.  Swimming  natural  and  easy  to  fishes  ;  its  mechanism,  367. 
Of  flying,  368.  The  structure  of  the  body  in  birds  favourable  to  this  ac- 
tion; how  performed,  369.  Of  crawling,  371.  All  the  phenomena  of 
animal  mechanics  may  be  referred  to  theory  of  the  lever  of  the  third 
kind,  370.  Partial  motions  performed,  by  the  upper  extremities,  360.  Of 
climbing;  of  pushing,  360.  Of  throwing  a  projectile,  360.  Partial  mo- 
tions, as  signs  expressive  of  ideas;  of  gestures  and  attitudes,  369. 

CHAPTER  IX. 

Of  Voice  and  Speech,  370. 

Definition  of  the  voice  and  of  speech ;  circumstances  necessary  to  the 
formation  of  the  voice ;  its  organs,  371.  Opinions  of  Ferrein  and  Dod- 
art,  on  the  uses  of  the  glottis,  371.  The  larnyx  is,  at  once,  a  wind  and 
a  stringed  instrument,  372.  Of  the  power  of  the  voice  5  of  speech ;  man 
alone  is  capable  of  speech,  373.  Of  the  vowels  and  consonants,  374.  Of 
song  and  music,  375.  Of  stammering,  burr,  and  dumbness,  375.  In- 
struction of  the  deaf  and  dumb,  376.  Ventriloquism,  52 1. 

SECOND  CLASS. 
CHAPTER  X. 

Functions  subservient  to  the  preservation  of  the  Species. 
Of  Generation)  381. 

Difference  of  the  sexses,  381.  Case  in  which  the  sexual  organs  did  not 
exist,  381.  Hermaphrodism  is  never  met  with  in  the  human  species,  383. 
Man,  in  the  exercise  of  the  functions  of  generation,  not  under  the  control 
of  the  seasons,  384.  Of  the  organs  of  generation,  in  man,  384.  Of  the 
female  organs  of  generation,  386.  Of  the  signs  of  virginity,  387. 

Of  erection,  386.  Of  the  human  semen,  388.  Of  the  ovaria,  390.  Of 
the  impregnation  of  the  ovum,  393.  Of  barrenness,  394.  Systems  of  ge- 
neration, 394.  Gestation,  397.  Of  the  foetus  and  its  coverings,  400. 
Of  the  development  of  its  organs,  400 — 40 1 .  Of  circulation  of  the  blood, 
in  the  foetus,  40 1 .  Of  the  placenta,  40 1 — 402.  The  umbilical  cord,  404. 
Mode  of  existence  of  the  foetus,  405.  Morbid  affections  to  which  it  is 
subject  while  in  the  womb,  406.  Of  monsters,  407.  Their  different  kinds, 
and  the  causes  which  produce  them,  408.  History  of  a  remarkable  case, 
409.  Of  the  chorion,  of  the  amnion  and  liquor  amnii,  409.  Of  the  allan- 
tois  and  urachus,  410.  Of  the  natural  term  of  gestation,  412.  Of  par- 
turition, 412.  Of  the  mechanism  of  parturition,  413.  Of  twins,  413.  The 
number  of  male  children  born  exceeds  that  of  temale,  414.  Of  superfce- 


INDEX. 


tations,  416.  Of  suckling,  418.  Sympathy  between  the  uterus  and  mam- 
mae ;  structure  of  the  latter,  419.  The  milk  appears  to  be  brought  to  the 
breasts  by  the  lymphatics,  420.  Chemical  qualities  of  the  milk,  420. 
Connexion  between  the  new  born  child  and  the  mother,  421.  Imperfect 
development  of  ihe  foetal  lungs,  422. 


CHAPTER  XL 

Containing  the  History  of  the  ages,  the  Temperaments,  and  the  Varieties  of 
the  Human  Species  ;  of  Death  and  Putrefaction,  421. 

Of  infancy  ;  of  detention,  422.  Ossification,  423.  Phenomena  of  puber- 
ty, 424.  Connexion  between  the  development  of  the  sexual  organs  and  the 
voice,  425.  Of  menstruation,  426.  Of  the  cause  of  menstruation,  426.  Of 
the  cessation  of  this  evacuation,  427.  Of  manhood,  428.  Of  tempera- 
ments and  idiosynbrasies,  429.  Of  the  sanguine  temperament,  430.  Of 
the  muscular  or  athletic  temperament,  433.  Of  the  bilious  temperament, 
produced  by  an  increased  energy  of  the  hepatic  system,  joined  to  con- 
derable  activity  of  the  sanguineness  system,  434.  Of  the  melancholic 
temperament,  434.  Lymphatic  temperament,  435.  Nervous,  435.  Mixed 
and  acquired  temperaments,  435.  Influence  of  climate  on  tempera- 
ments, 435. 

Varieties  of  the  human  species,  436.  European  Arab  race,  436.  Ne- 
gro, 437.  Mogul,  437.  Hyperborean,  437.  Moral  characteristics  of  the 
different  races,  438.  Giants  and  Dwarfs,  439. 

Of  old  age  and  decripitude,  439.  Decay,  439.  Death,  441.  Gradual  ex- 
tinction of  bodily  and  mental  powers,  in  the  reversed  order  of  their  pro- 
duction, 442.  Period  of  death,  443.  Probabilities  of  human  life,  444 — 
446.  Of  putrefaction,  446 — 448. 


Notwithstanding  all  the  care  we  have  bestowed  on  this 
volume,  some  unavoidable  literal  errors  will  be  found  in  dif- 
ferent parts  of  the  work  ;  these  being  obvious,  the  reader  is 
requested  to  correct  for  himself. 


14  DAY  USE 

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